GTA
All Springer/NP/PCP Air Gun Discussion General => "Bob and Lloyds Workshop" => Topic started by: rsterne on December 31, 2015, 02:09:32 AM
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A while back on my .30 cal Grizzly HPA I tried a new system on the hammer spring.... It rides on a guide that is adjustable in length and comes to a positive stop just before the front of it hits the inside of the hammer.... The idea is to use a long, light hammer spring, which is easier to cock, and preload it on the guide.... This increases the initial cocking force, but reduces the final cocking force, making the gun smoother and lighter to cock.... What I thought I achieved was also a reduction or elimination of hammer bounce, which reduced wasted air and increased the efficiency.... I used the same design in my new Monocoque PCP, but of course it is yet untested.... So I decided I would take a gun I was familiar with and build one of these guide stops to see if I could document any increase in efficiency.... BOY, DID I !!! ....
The gun is a 2560.... ie a 2260 converted to a PCP, with a .25 cal LW barrel on it.... The valve has been hogged out, and the gun breathes extremely well.... The standard setup is a 1.75" x 0.040" wire spring on a Challenger Power Adjuster (RVA).... I use this gun for testing because it has a small reservoir so I don't have to shoot a lot to test changes, but it is big enough at 65 cc to not lose power in this .25 cal setup which is tuned for about 50 FPE with 25.4 gr. JSB Kings.... Here is a plot of the Velocity vs Preload with the gun tethered to a regulator with a 1900 psi output (actually 1880 according to the gauge I used for these tests)....
(http://i378.photobucket.com/albums/oo221/rsterne/Discovery/2560%20Test%20Gun_zpsq8kpc9as.jpg) (http://s378.photobucket.com/user/rsterne/media/Discovery/2560%20Test%20Gun_zpsq8kpc9as.jpg.html)
As you can see, this is pretty much the perfect spring for the gun, and the knee of the curve, where the gun starts gaining efficiency without losing much velocity, is at 4-5 turns out from coil bind.... I then chose a setting of 5 turns out and shot a string with the gun tethered but the SCUBA tank turned off.... The hoses were full, one going into the regulator and the other out, along with a gauge, so the total volume works out to 90 cc.... I got 5 shots starting at 938 fps, peaking at 950, and ending at 904 fps, and the pressure at the end was 1120 psi, so the gun used 760 psi of air, and got an efficiency of 0.85 FPE/CI.... While this in not great, don't forget that this a 50 FPE string from 1880 psi down to 1120.... I couldn't hear any hammer bounce on the first shot, but as the pressure dropped I heard more and more of that telltale B-RR-AAA-PPPP indicating it was wasting air.... I then installed the new preloaded setup, which uses a 2200 hammer spring with 0.80" of preload, which works out to over 5 lbs.... However, the maximum force to cock the gun is only 9.5 lbs. instead of over 10.6 lbs. with the original setup, which had a preload of less than 1.5 lbs.... Here are the two setups tested....
(http://i378.photobucket.com/albums/oo221/rsterne/Discovery/Challenger%20RVA%20and%20Preloaded%20RVA_zpsd2mz4f48.jpg) (http://s378.photobucket.com/user/rsterne/media/Discovery/Challenger%20RVA%20and%20Preloaded%20RVA_zpsd2mz4f48.jpg.html)
You can see the guide, made from a 3" long piece of 3/16" drill rod, threaded 10-32 on both ends.... The front nut is turned down to fit inside the hammer, and at the rear are two nuts locked against each other to adjust the preload.... The 3/8" hex head bolt is drilled through for the guide, and allows you to position the front of the guide just clear of the inside of the hammer.... It is longer than needed, and if shortened 1/4", the guide could be shortened the same amount, making it more compact.... Here are photos of the gun, first uncocked, and then cocked, so that you can see what is going on....
(http://i378.photobucket.com/albums/oo221/rsterne/Discovery/Preloaded%20Spring%20Guide%20Uncocked_zpsrmmciube.jpg) (http://s378.photobucket.com/user/rsterne/media/Discovery/Preloaded%20Spring%20Guide%20Uncocked_zpsrmmciube.jpg.html)
(http://i378.photobucket.com/albums/oo221/rsterne/Discovery/Preloaded%20Spring%20Guide%20Cocked_zpsqtzb0nsb.jpg) (http://s378.photobucket.com/user/rsterne/media/Discovery/Preloaded%20Spring%20Guide%20Cocked_zpsqtzb0nsb.jpg.html)
The small O-ring just acts as a cushion when the guide crashes to a halt.... The hammer then carries on, coasting on its own to open the valve to the appropriate lift and dwell.... The magic occurs on the return trip.... Since the spring is not touching the hammer while the hammer is touching the valve stem, as the valve closes it does not store any energy in the spring.... When the valve closes, the hammer has to move a bit further before it touches the spring guide, but instead of having a spring with little or no preload, which is easy to compress, it hits the end of the guide, which can't move unless you push on it with over 5 lbs. of force.... so it doesn't budge.... the hammer rattles to a stop between the valve stem and the spring guide, and doesn't have enough energy to open the valve for a second time.... No hammer bounce, so no wasted air, and instead of 5 shots.... I got 7, and used less air doing it.... While the shots got louder as the pressure dropped, as expected, NONE of the shots, even the last one at the lowest pressure, had that telltale burp of wasteful hammer bounce.... Here are the two shot strings....
(http://i378.photobucket.com/albums/oo221/rsterne/Discovery/2560%20Test%20Gun%20New%20Preloaded%20Spring_zpsoxqbqamv.jpg) (http://s378.photobucket.com/user/rsterne/media/Discovery/2560%20Test%20Gun%20New%20Preloaded%20Spring_zpsoxqbqamv.jpg.html)
The two curves on the graph are the average of two strings each, where individual shots only varied by a few fps.... You can see that the starting velocity at 1880 psi is the same, but look at how fast the pressure drops with the original setup, compared to the new one with the preloaded guide that stops before the hammer hits the valve.... Instead of using 760 psi for 5 shots, the gun now uses only 620 psi for 7 shots, starting at the same 1880 psi and ending at 1260.... This gives an efficiency of 1.48 FPE/CI.... which is absolutely stunning for a 50 FPE gun at these pressures.... I NEVER expected to see such a huge difference.... It sure shows how much air a PCP can waste if the hammer is bouncing enough to hear it....
I shot a 10 shot string with the gun tethered at 1880 psi, and the ES was just over 1%, about 11 fps.... That is pretty typical.... One thing I noticed is how fussy the preloaded setup is to tune.... The amount of preload is the "coarse" adjustment, you have to get enough so that the average spring force, with the longer, weaker spring, is a bit more than the standard setup.... I found that the best setup for the clearance between the end of the guide and the inside of the hammer, in this case, was very close, about 0.030".... This may have to do with the rather short hammer stroke on a Disco, about 0.67" on this gun (and that is longer than stock).... It turns out that each flat on the adjusting bolt (about 0.010") is about 10 fps of velocity.... Coil bind with this spring was about 985 fps.... One thing I have done on the Monocoque PCP, which I think is a good idea, is to drill the inside of the hammer large enough that the spring and the end of the guide cannot touch the sides of the hole.... so that there is no chance of extra drag on the hammer.... It does, after all, have to open the valve while coasting....
This setup worked so well that I plan to retrofit all my PCPs eventually.... It does take a bit of extra length to accomdate the hammer spring, because you need a longer, weaker spring.... but not excessively so.... How can I pass up the opportunity to use something that, in this case, improved the efficiency by 74%.... We do need to come up with a good name for it, though....
Follow through the thread and you will see this device is now called the Stopping Spring Guide or SSG for short....
Bob
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AZ ( Alan Z )tunes the Brit Theobens very similar in that NO preload is used having hammer do the coast to impact thing.
Great idea bob given the room to have the mechanics of it not interfere with your grip hand.
* Now, would not having the rod holding spring be better yet if LIGHTER ?
would seem the weight of the rod being accelerated along with hammer slows up the lock time some.
also being its weight contributes nothing to the hammer energy upon poppet ... lighter is better, no ?
Also if i understand this correctly ....
The jam nuts hold head of spring rod off the hammer at impact yet bottoms out against bolt used for preload.
So ... any changes done to preload ALSO require resetting the rods depth ?
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we did something similar with the FLEX it has 1/2 of free play on the hammer spring with no pretension and runs on twin guides. Prevents all hammer bounce and any spring bind or deflection. But this has to be built into the gun design because you need a lot of hammer throw for this to work or you end up having very stiff hard cocking effort. Good work there Bob.
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We do need to come up with a good name for it, though....
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Since I have a Norwegian last name and it controls the Hammers Strike...
I'm all in for calling it...
Thor
;)
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I have been using short heavy springs with negative preload for quite a while, the idea started here in North America a few years ago by Lloyd Sikes.... It can reduce hammer bounce to be sure, but the price you pay is greater cocking force required at the end of the cocking stroke.... For whatever hammer energy and momentum you need it is the AVERAGE spring force and the hammer travel that generate it.... Don't confuse how this setup works with a short heavy spring with no preload.... they are VERY different.... Cock one and then the other, and you will see....
I agree with you that the weight of the spring guide must be accelerated by the spring, but does nothing to the valve.... So, the lighter you can make the guide, as a percentage of hammer weight, the better.... If you are dealing with a regulated PCP, and tune it to be efficient, you likely have little hammer bounce anyway.... However, most unregulated PCPs tend to have at least some bounce at the low pressure end of the string, and some poorly tuned ones even at the high pressure end.... I have never been a fan of any HDD that uses friction to slow the hammer, because as well intentioned as they may be, most seem to hinder the hammer on the strike as well as the rebound.... When you start playing around with Big Bores, hammer bounce is something that for the most part hasn't even been addressed....
Some guns may not benefit from this idea.... but others obviously will.... It's just one more tool in the toolbox, to use or throw away, as you see fit....
Bob
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Here is a comparison of the cocking effort of three springs.... a 10 lb/in. with negative preload, an 8 lb/in that just touches the hammer, and a 6 lb/in which is preloaded to just 2 lbs and fitted to a guide that clears the hammer by 0.1".... In all cases the hammer stroke is 1", and the average hammer force is the same....
(http://i378.photobucket.com/albums/oo221/rsterne/Discovery/Hammer%20Spring%20Stop_zpsyrqca3hf.jpg) (http://s378.photobucket.com/user/rsterne/media/Discovery/Hammer%20Spring%20Stop_zpsyrqca3hf.jpg.html)
Two things to note.... First, the maximum cocking force is less with the preloaded, weaker spring.... Second, if the hammer rebounds from the valve with a force of 1 lb., it won't compress the 6 lb/in preloaded spring.... but it can compress and store energy in the other two.... I hope this explains the difference....
Bob
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Scott, yes, a change in preload will change the depth of the end of the guide inside the hammer.... so you will need to adjust the large bolt to reset that.... In practice, you will find that once you get the preload you need, you could cut the end of the guide off flush with the nuts and forget adjusting it.... The main adjuster will then give you all you need.... As you back if off, increasing the distance of the end of the guide from the inside of the hammer, you reduce the distance the spring is compressed, and lose power in a hurry.... A fine thread on that bolt would be a very good idea....
Bob
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Scott, yes, a change in preload will change the depth of the end of the guide inside the hammer.... so you will need to adjust the large bolt to reset that.... In practice, you will find that once you get the preload you need, you could cut the end of the guide off flush with the nuts and forget adjusting it.... The main adjuster will then give you all you need.... As you back if off, increasing the distance of the end of the guide from the inside of the hammer, you reduce the distance the spring is compressed, and lose power in a hurry.... A fine thread on that bolt would be a very good idea....
Bob
It now is clear ....
Once preload known to get at OR above target power, any BACKING off on preload has the stop rod actually bottoming out on head of preload bolt sooner and the length of hammer coast to poppet impact actually increasing .... Cleaver indeed !
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Bob, Very informative. Thanks for sharing.
Happy Pneu Year to all.
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Hey Bob,
Thanks for bringing to the Masses what the Custom Shops are already doing 8).
I need to think about working this into some of my guns ;).
A 74% increase in efficiency is like having two days of Christmas ;D.
Kirk
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Im learning something every day you with you guys
Cheers
Jay
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My apologizes for freaking out on Tomg's post about the great performance when using the loaded spring guide..
Bob,
Excellent results and great explanation of what your doing with a pre loaded spring guide. This post reminds me of when I questioned about the 1cc fpe rule and now I see where you are suggesting 1/2cc with a slightly increased pressure for the same fpe at a greater efficiency (please don't ask me to look for the posts) now.
After doing all this I really do appreciate all the work you do because this exercise took a while.... :D
Without all the details of the springs,ect, I conjured up at much as I can from what you posted to put together some interesting data (please keep in mind without all the specs/data- all hypothetical).
The first chart is of your gun above demonstrating preload vs fps. My chart (without "real specs/data of the spring and other stuff") shows the cocked hammer force/preload against valve, and cocking strength over the length of travel.
What it tells you (I think), if you set the rva to -7 you would see the same (perfomance) ES% (ofcourse more shots) as the loaded spring since at this setting the hammer is now floating similar to the loaded spring guide. But, as you can see from the chart, there is not enough hammer energy to get you back to the 50 fpe range.
Hence,
If you put an 8lb per inch spring in there with the same "negative preload" (the next chart) you will see that you can get back to the same power level as the loaded spring guide with the same cocking effort (which should be "almost" identical to using the loaded spring guide "I think").
It also shows you how pre-load affects dwell which wastes air and in you case the valve is maxed open at 13.5 lbs (hypothetical numbers).
I really do get the fact that using the loaded spring vs short stiff spring is the difference of force at the " spring free length" Whats missing for me is the in-elastic or elastic collisions between the hammer hitting the valve and the hammer bouncing back to the spring. I am not sure how much energy is produced to bounce the hammer against the hammer spring to influence enough force to crack the valve again when using the "negative" preload spring or negative loaded spring guide. If I had to guess, it's mice nuts when both systems are set up correctly.
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Thanks for sharing this Bob. Hammer bounce is definitely one of the top 3 causes for poor efficiency.
Just to add to the discussion: I have had very good results with mechanical hammer stops, where I was still able to use spring tension without affecting hammer bounce. As an example, the Hatsan BT65 has a very simple and effective anti-hammer bounce lever, which when fine tuned can stop the hammer immediately on return. I was able to tune a Carnivore with a 14 shot string starting at 2600 PSI down to 1600 PSI averaging 953 fps (JSB 50 gr, 15 fps ES) with an efficiency of 1.4 FPE/CI, which is unheard of for a big bore. http://www.gatewaytoairguns.org/GTA/index.php?topic=95228.msg891086#msg891086 (http://www.gatewaytoairguns.org/GTA/index.php?topic=95228.msg891086#msg891086) Since hammer bounce was not an issue, I was able to trade large dwell/lift for high FPE at lower than expected pressures.
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The 1 cc per FPE is still better, if you have a large tank (bottle) feeding the gun.... ONLY if you are running an in-tube regulator (where you have to trade off reservoir volume for plenum) does it make sense to use 1/2 cc per FPE.... BIG difference between the two, and something I admit I missed originally, because I don't use, or like, in-tube regulators exactly for that reason.... However, if that is what you must use, then the 1/2 cc per FPE (plus or minus), with an increase in setpoint, is likely going to give you more shots....
First of all, there is only 0.67" of hammer travel in this gun, not 1".... Second, as you can see, no amount of spring will give you 1025 fps at 1900 psi with the existing porting, even with a dump shot.... You are correct, that using the 10 lb. spring with negative preload will not produce 50 FPE, in fact that doesn't occur until about 8 turns out (24 TPI on that adjuster), down at about 29 FPE.... The only way you could get 50 FPE with negative preload would be to use a stiffer spring (12-15 lb/in), and that would make the gun nearly impossible to cock.... Basically, you can't get there from here....
When you do your graphs for force vs. distance, for the preloaded guide setup you need to have a completely vertical line when the hammer first contacts the end of the spring guide, because it won't move at all (other than the O-ring decompressing a couple of thou) until you are pulling on the bolt hard enough to overcome the preload.... The graph I posted in Reply #5 was GENERIC to demonstrate the differences, not specific to this gun.... but it does show that vertical segment.... In this gun, that line would go straight up to over 5 lbs., but only about 0.030" from where the hammer starts when against the valve....
There is no question that a short, stiff spring with negative preload is vastly better at preventing hammer bounce.... and that a spring that JUST touches the end of the valve stem at rest is likely the worst possible setup.... Adding preload, or creating a space, both work better.... and in most cases the space works the best.... The downside is that when you are trying to get lots of power out of the gun, running it up on the knee of the preload curve, to accomplish that you need a VERY stiff spring.... and that makes the gun VERY hard to cock at the end of the cocking stroke.... Not an issue with a low-powered gun.... but a serious problem when you are pushing the FPE, and particularly for Big-Bores.... I think that if guys take the time to play around with this idea, they may be pleasantly surprised to get the same power, lighter smoother cocking, and better efficiency, all at the same time.... As I said, I plan to retrofit many (if not all) of my PCPs.... What I don't know at this point in time is how much difference it will make on a regulated gun that is already quite efficient.... but you can bet I will find out, and share those results, good or bad....
I am aware of the Hatsan anti-bounce lever, and there is no question that it works.... What surprises me is that the Hatsan is not more efficient than it is.... Perhaps the hammer on the stock Hatsans can move too far before hitting the lever and stopping, and so still bounces a bit?.... Or, perhaps since the spring is preloaded while against the lever there is enough stored energy to reopen the valve?.... I have never explored it deeply enough to find out.... Certainly they can be a bit of a pain when they fail, which has been seen more than once....
Bob
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Bob,
Thanks for sharing this with us. You have taken the known problem of hammer bounce (particularly at lower pressures) and attacked it in a different way. (at least it is new and novel to me!) Based on the laws of conservation of energy and conservation of momentum, I can see where a large portion of the rebound energy in the hammer, in its first bounce, is transferred into the spring adjuster rod, and the residual energy in the hammer is now inadequate to open the valve a second time. It makes perfectly good sense. I can also see that if the adjustment rod were made too light, that it wouldn't be able to drain enough energy out of the hammer to prevent the bounce. This looks like a very tuneable arrangement. Very good!
Lloyd
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Lloyd, you may be right.... There could be an optimum relationship between hammer mass and the mass of the spring guide so that the momentum transfer won't allow it to move.... I have difficultly wrapping my brain around the difference between a guide that weighs 5 lbs. and one that weighs 1/2 oz. with 5 lbs. of preload against it, from a Physics point of view.... The 5 lb. guide has more mass, but the 1/2 oz. guide acts like it is in a gravitational field exerting 320 G against it (the spring).... Makes my brain hurt to try and understand how they both react when struck by a 2 oz. hammer being thrown back by the valve.... Fortunately for me, it works regardless.... *LOL*....
Bob
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Impressive Bob. Yet another ejication on the fisicks of air gun internals. You should be getting royalties off this stuff ;D
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I am aware of the Hatsan anti-bounce lever, and there is no question that it works.... What surprises me is that the Hatsan is not more efficient than it is.... Perhaps the hammer on the stock Hatsans can move too far before hitting the lever and stopping, and so still bounces a bit?.... Or, perhaps since the spring is preloaded while against the lever there is enough stored energy to reopen the valve?.... I have never explored it deeply enough to find out.... Certainly they can be a bit of a pain when they fail, which has been seen more than once....
Yes, the stock Hatsan BT platform does not seem to yield any increase in efficiency from the use of the anti-bounce lever. Part of this is due to the short lift, hence forcing owners to rely primarily on dwell for increased performance over a wide range of pressure (91g hammer, 1" travel, 2-3/4" ~12lb/in spring) As you know, the additional holes on the valve (increased dead space) directly affects efficiency as well. I don't have a picture of it, but the AT anti-bounce lever is considerably weaker than the solid/1-piece BT anti-bounce lever (same principle though). I have not heard of a failure on the BT platform, but as you said, several on the AT.
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Soon as the holidays are over ... am going to further this R&D on a couple of my Regulated guns already using very Light hammers.
BOTH the Marauder & RAW platforms use hollow end spring tension caps & guides that very easily would take a center stem with a cup to hold spring off bottom of hammer spring bore while allowing a stop to impact back side of tension cap.
In my case of mostly sub 50 ft lb ( Most 16-30 lb ) target/light hunting rifles set up to have minimal bounce already, such a test certainly should be telling if bounce is eliminated further by an increase in efficiency ???
or ... be telling bounce is already been mitigated.
Looking forward to this !!
** Am thinking of using a Stainless Bicycle or Motorcycle spoke silver soldered into a machined cup that would sit in bottom of hammers spring bore, then use the nipple threading at end of the spoke ( Obviously cut to optimum length first ) to take the jam nut or perhaps creatively a way to use the spoke nipple ;)
Keep it light yet strong with minimal mass / obtrusiveness.
Thanks Bob !
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I noticed this is working on a lower psi setup. Will it still work at higher psi loads that require more force to open the valve and keep it open long enough? Will you still be able to produce a bell curve?
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hmm the T.H.O.R. system does work guys...
Tunable Hammers Of Robert (Bob is short for Robert so I assume, maybe wrongly)...
Tunable Hammer Opposing Rebound... so it would mean it function also...
Sensei is ignoreing the class idjit... ;) ;)
and I have worked a hard five min on this...
The only possible problem is maybe metal fatigue after thousand of cycles of the hammer hitting the stop portion of the guide...
Almost wish I was Canadian and had 2 PALs...
Just what my Buc needs... Hmm can this be made a full rear cocker somehow?
Could it adjust from 20 fpe down to 10-12 fpe on something like my Buccaneer? (in conjunction with fill pressure)
hmm sure would be fun testing...
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I am already using it on my .30 cal Grizzly, which is regulated at 2200 psi.... I did notice a reduction in "BURP" and a slight increase in efficiency, but it was already pretty good.... When I get the Monocoque PCP in service we will get our answer in a high pressure, unregulated version, as I am looking for a bell curve from 3800 psi down to 3000 or so, at over 200 FPE !!! ....
Scott, I like the idea of a Bicycle spoke, only thing I can think of is that since the spring is compressed all the time it may not stay straight if the spoke is too small relative to the ID.... Perhaps a plastic sleeve over the outside, I have already thought of that idea, problem is drilling a long, small hole, maybe?.... or possible find a piece of plastic tube that will do the trick, without adding drag inside the bolt that guides the guide?....
Bob
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For a name, I have been toying with "Slapshot" like in Hockey (from the Great White North).... Wind that hammer up and let it fly!.... *LOL*....
Bob
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Motorhead,
As an Idea:
On the maurader (with a little creativity) you can use a degassing tool to make the spring guide and use the same cap along with the existing HT to control the mechanism.
Zandrew,
The loaded spring guide will work just like any other spring with just the limitation of a higher working spring at a shorter length.
To Zandrews point,
This is why I prefer using the heavier shorter spring with negative preload IMO. For example, I run a 20 to 22lb per inch spring on my marauder at a length of 1.8" long. When people hear this they say holy moly are you crazy and how do you cock it.
Well at 1.8" spring length there is .4 inches of head space in there. So, at 0 on the HS, it's like cocking the gun with a 6 to 8 Lb spring and when the HS is set at 7 to 7.5 it's the same cocking strength as a 15 to 17 lb spring. This allows the you to achieve maximum spring force (in my case 56fpe-25.39 grains) at 3000 psi (high power tune) to running a low pressure tune of 2000psi down below 1000 psi hitting just under 20fpe using 14.3's.
In all the hammer spring adjustments, my system runs negative preload through the entire HS adjustment. When you start adjusting HT, that's when you begin losing negative preload and travel.
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Bob,
Have you figured out to incorporate this into a cocking rod? I will ponder that too. Hmmmmmm
Lloyd
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Bob,
Have you figured out to incorporate this into a cocking rod? I will ponder that too. Hmmmmmm
Lloyd
Lloyd,
was thinking that too ... BUT sadly with Bobs idea there is no mechanical connection between the Rod and Hammer.
so while you can play pin ball launch all day long, hammer just sits there un-moving.
Tho it does make a nifty action COCKED indicator.
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Scott, I like the idea of a Bicycle spoke, only thing I can think of is that since the spring is compressed all the time it may not stay straight if the spoke is too small relative to the ID.... Perhaps a plastic sleeve over the outside, I have already thought of that idea, problem is drilling a long, small hole, maybe?.... or possible find a piece of plastic tube that will do the trick, without adding drag inside the bolt that guides the guide?....
Bob
In thinking about this most of the morning ... my concept of this is TO KEEP the spring cavity of hammer as they are being within @ .020" of the hammer spring O.D. letting the bore be the spring guide upon compression.
Even when hammer is down on poppet the hammer spring is still well within the bore cavity of hammer.
The HAT spring sits upon connected to rod only needs to be at a diameter equal to that of the spring.
There centering to one another done by the bore diameter of hammers spring cavity.
* So to your concern over spring at rest being under tension hung on this stop rod creating a cant/ bending of rod issue ... Where can the spring go ???
Doing it in this way the stop rod is basically free to float as it passes threw tension cap only needing a localized minimal length guide/bearing surface to mitigate drag. Then bumper to damp the impact of spring/rod violently coming to an abrupt stop.
Just a few thoughts on utilizing design.
Scott
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Bob,
Have you figured out to incorporate this into a cocking rod? I will ponder that too. Hmmmmmm
Lloyd
Lloyd,
was thinking that too ... BUT sadly with Bobs idea there is no mechanical connection between the Rod and Hammer.
so while you can play pin ball launch all day long, hammer just sits there un-moving.
Tho it does make a nifty action COCKED indicator.
Darn, I was hoping for a "pellet-in-the-chamber" indicator.
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Lloyd, that seems obvious, since the guide sticks out the back.... The one TomG did even had a Delrin knob on the back.... but pulling on the knob doesn't move the hammer, it only compresses the spring.... I don't know how you would connect the hammer to the rod and still have it fly freely....
Scott.... I think if the hammer bore can drag on the spring it may not fly easily.... may drag on the spring at launch and lose energy and/or be inconsistent.... I think I was seeing some of that last night during adjusting.... My Monocoque PCP has an oversize hammer bore to insure this cannot occur.... I have used a moving spring guide as a cocking indicator many times in the past.... It is captured between the spring and the hammer by the spring force, and adds to the hammer mass.... You can even use it to directly measure valve lift by sliding an O-ring over it....
RE supporting the spring on the outside, the spring could be contained inside the hammer, and/or inside the hollow adjusting bolt to keep it straight.... but even then in the uncocked state, there would be a portion of spring that could not be in either the hammer or guide bolt (minimum of the length of the stroke).... The spring has to collapse that distance and enter either the hammer or guide bolt, or both.... doesn't it?....
Bob
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Lloyd, that seems obvious, since the guide sticks out the back.... The one TomG did even had a Delrin knob on the back.... but pulling on the knob doesn't move the hammer, it only compresses the spring.... I don't know how you would connect the hammer to the rod and still have it fly freely....
Scott.... I think if the hammer bore can drag on the spring it may not fly easily.... may drag on the spring at launch and lose energy and/or be inconsistent.... I think I was seeing some of that last night during adjusting.... My Monocoque PCP has an oversize hammer bore to insure this cannot occur.... I have used a moving spring guide as a cocking indicator many times in the past.... It is captured between the spring and the hammer by the spring force, and adds to the hammer mass.... You can even use it to directly measure valve lift by sliding an O-ring over it....
RE supporting the spring on the outside, the spring could be contained inside the hammer, and/or inside the hollow adjusting bolt to keep it straight.... but even then in the uncocked state, there would be a portion of spring that could not be in either the hammer or guide bolt (minimum of the length of the stroke).... The spring has to collapse that distance and enter either the hammer or guide bolt, or both.... doesn't it?....
Bob
As to the first Q ...
The spring sitting on the rod hat at full cock position IS NO DIFFERENT than a conventional design being they follow each other and only each coil of spring as it decompress's are in motion against spring bore within hammer.
Same same drag dynamic.
ONLY WHEN the rod is stopped does hammer travel independent of spring. And were talking what ? ... less than .050"-.100" or so. So would think drag issue being in effect over such a short distance are mininimal ? ... maybe I'm wrong.
At to the second Q ...
Yes spring outside of hammer cavity is unsupported for cant/tilt ... But could be easy enough using a short I.D. guide retained at rear cap end. Upon compression it simply enters the hammer bore on spring I.D. while O.D gets held by hammers bore. * Overlap and interference based upon stroke used, depth of hammer bore & rear guide length.
Hard to get all the words in on thoughts ... sorry about that.
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The hammer travels independent of the spring/guide for the clearance between the two at rest, plus the amount the valve opens.... I would think any additional drag could reduce the lift and dwell.... If it reduced the lift from 0.080" to 0.070" (with a corresponding decrease in dwell) that would be very significant, no?.... In a conventional setup, if the spring preload is greater than the lift, the spring travels with the hammer the entire round trip with the valve.... With a stiff spring and negative preload, there is no force on the spring to kink it sideways and slow down the hammer.... With my setup, there is the potential for that extra friction between the inside of the hammer and the spring/guide, and my gut feel is that it is important that any possibility of it be eliminated....
Bob
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The hammer travels independent of the spring/guide for the clearance between the two at rest, plus the amount the valve opens.... I would think any additional drag could reduce the lift and dwell.... If it reduced the lift from 0.080" to 0.070" (with a corresponding decrease in dwell) that would be very significant, no?.... In a conventional setup, if the spring preload is greater than the lift, the spring travels with the hammer the entire round trip with the valve.... With a stiff spring and negative preload, there is no force on the spring to kink it sideways and slow down the hammer.... With my setup, there is the potential for that extra friction between the inside of the hammer and the spring/guide, and my gut feel is that it is important that any possibility of it be eliminated....
Bob
For argument sake .... When hammer gets to this last bit of travel it is UP TOO SPEED. Any small drag losses from a few spring coils against hammer as we're talking ( If at all ) IMO won't even be noticeable.
In the case of Nylon hammers as I use, there would be no drag as would a steel hammer with a smooth surface finish against the smooth spring coils.
For argument sake :o :o :o
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Just trying to give you possible problems.... hopefully you won't experience them....
Bob
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Going to have to try this on the Marauder. Can make a comparison between a Wicked NBH and a slug made of 12L14.
The Marauder hammer is larger, so its spring can be a larger ID, and maybe I will try an AL spring adjuster/guide.
cheers,
Douglas
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For a name, I have been toying with "Slapshot" like in Hockey (from the Great White North).... Wind that hammer up and let it fly!.... *LOL*....
Bob
Maybe combine the THOR idea someone had with your Canadian Hockey idea (and your first name) and call it (are you ready??)... The "Bobby Thor" System. (or isn't Bobby Orr playing anymore...)
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Nah,
I do not think they would make the connection...
they would be "Who is this English cop Thor and why is it named after him?"...
and there was a Paul Newman film so that the term Slap Shot for me/others? brings a different connotation/image to mind than you may intend... ;)
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I have to think this would work well on a co2 gun also.
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Quite possibly.... A lot of CO2 guns waste a lot of gas from too much dwell, also.... particularly if they have short barrels....
Bob
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This may sound stupid to you Bob, but I just thought of another possible way to do what you're doing with the springs here. Forgive me if someone has already talked about this also. Have you considered using a fluid damped hammer, or some sort of shock absorbed set up? I'm thinking something along the lines of the shocks on an off-road RC car. Those little shocks can take some real abuse, and you change the damping by the weight of the shock oil and the holes inside the shock. I know when I used to race the 1/10 scale stadium trucks, I would often run soft springs with thicker shock oil to get get the suspension soft enough to hook up without bottoming out on the jumps. I wonder if this could be adapted somehow in the hammer set up? If the shock fluid was just thick enough to not give during the hammer acceleration, but thin enough to give a little on the strike, that would surely reduce/get rid of hammer bounce. What do you think, am I crazy, or is this a good idea? This spring/hammer talk just got my gears turning is all...
These are some of the shocks I'm referring to for an example of possibilities or ideas. As you can see there thousands you could start with to modify. This is just one seller, and they don't even to begin to cover all of the ones out there.
http://www.integy.com/st_main.html?p_catid=312&p_prices=&page=1#.VoYndfkrIgs (http://www.integy.com/st_main.html?p_catid=312&p_prices=&page=1#.VoYndfkrIgs)
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I'm thinking this might be usable for an air conserving pumper tune.
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Great work Bob for doing the comparison of the two, it clearly shows the potential of the system.
I have yet to find time to do my own findings on mine, which is regulated, but as I stated in the other thread, the ES went down dramatically. Sound went down as well (efficiency increase)
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I don't know if something like those shocks could be used or not, I suppose anything is possible.... I certainly don't like the HDDs that rely on friction....
This idea would probably work great for converting an MPP to an ACP.... In fact, I wouldn't be surprised if many pumpers that we think are dumping all the air on the first shot are actually emptying the valve via hammer bounce anyway.... after Elvis has already left the building.... The only difference between an ACP and a PCP is the onboard pump, functionally....
I agree, Tom, the difference in the report was dramatic.... Not only does the version with the guide stop have no audible hammer bounce, the very last shot, at the lowest pressure, is quieter than the 3rd shot without it.... while without it the gun keeps getting (a lot) louder as the pressure drops.... We all know that noise is an indication of wasted air....
Bob
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Happy New Years day Bob and all you guys and gals...
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Thank you Bob ....
Lazy New Years day so why not fiddle some ;D
Test platform the .22 Marauder w/Reg & Bottle. Before doing this was at 865 fps with 18.1 jsb.
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First pictures the parts made up after thinking of a simple way to set up, be 100% reversible without being getto with the actual modification.
(http://i1320.photobucket.com/albums/u532/scott_schneider1/DSCF9916_zpsby5uh0jz.jpg)
(http://i1320.photobucket.com/albums/u532/scott_schneider1/DSCF9915_zpsumomw8jh.jpg)
(http://i1320.photobucket.com/albums/u532/scott_schneider1/DSCF9914_zpsh8pmm3g4.jpg)
Used a 8-32 threaded blind nut and long SS 8-32 screw. Machined up a Delrin AF collar to be the seat for spring & center it within hammer bore. Then a 3/8-24 threaded guide that screws into back of velocity adjuster cap.
* the long screw into the blind nut adjusts over all length between the two, keeps the assembly minimally invasive when cocked and just looks clean ;)
Assembled it looks like this ...
(http://i1320.photobucket.com/albums/u532/scott_schneider1/DSCF9912_zpscdbcabrr.jpg)
(http://i1320.photobucket.com/albums/u532/scott_schneider1/DSCF9911_zpsxkogzryl.jpg)
Assembled onto rifle like this in the fired position ...
(http://i1320.photobucket.com/albums/u532/scott_schneider1/DSCF9917_zpsyfmsbhfa.jpg)
And when cocked like this ...
(http://i1320.photobucket.com/albums/u532/scott_schneider1/DSCF9918_zps9w9v1ibu.jpg)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
How it shoot ??? .... well as Bob had made note, I need more spring energy due to the losses of losing the actual extar push of hammer spring against poppet valve. I did get more preload on my spring but it is not enough to get equal power currently. with the same pellet were right at 800 fps having lost @65fps.
Shot cycle VERY crisp with a quieter muzzle report as well. Over the chrony 2 mags shot ES was staying +/- 3 fps.
Valve is quite obviously getting a very consistent strike 8)
All I got to share at this time :-X
Good mod Bob, will get a tad more spring energy and try and get power back to my ideal 865 fps soon as i source the parts.
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Motorhead,
You may not see any benefits to this design when using your light weight hammer. One of the benefits that Bob is mentioning is a smoother/lighter (feeling) cocking.
It already appears as if your running a stock 6 to 8 lb spring on the loaded guide. Going higher kind of defects the idea.
It also appears (if your running a 6 to 8 lb spring already) you system depends on the extra dwell caused by the preload to achieve that 865fps.
If perhaps that is the case, then you have 2 ways to show how your light weight hammer (in it's current configuration) or loaded spring guide (with standard weight marauder hammer) improves shot count.
I bet if you put a stock hammer in there (replace HT with set screw) and the the loaded spring or short stiff spring with negative preload you will see similar to if not the same results as just running the light hammer with your standard spring. ;)
It also may show that when running a loaded spring guide or short stiff spring with negative preload that the in-elastic collision from hammer to valve stem is becoming more elastic, reducing the dwell at the same lift and the hammer is not following the valve stem as much during the initial strike.
Trying it out with the stock hammer can't hurt and I am sure you have the parts to just drop in and test :D
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Hope you don't mind but I am tagging the post for future research.
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So why not just have a short spring fire the hammer at the valve, with space between a fully extended stiff spring and the valve stem there would have to be less rebounding anyway. Maybe a rubber button on the end of a spring guide to deaden rebound and have the other end secured in the end cap.
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Motorhead,
You may not see any benefits to this design when using your light weight hammer. One of the benefits that Bob is mentioning is a smoother/lighter (feeling) cocking.
It already appears as if your running a stock 6 to 8 lb spring on the loaded guide. Going higher kind of defects the idea.
It also appears (if your running a 6 to 8 lb spring already) you system depends on the extra dwell caused by the preload to achieve that 865fps.
If perhaps that is the case, then you have 2 ways to show how your light weight hammer (in it's current configuration) or loaded spring guide (with standard weight marauder hammer) improves shot count.
I bet if you put a stock hammer in there (replace HT with set screw) and the the loaded spring or short stiff spring with negative preload you will see similar to if not the same results as just running the light hammer with your standard spring. ;)
It also may show that when running a loaded spring guide or short stiff spring with negative preload that the in-elastic collision from hammer to valve stem is becoming more elastic, reducing the dwell at the same lift and the hammer is not following the valve stem as much during the initial strike.
Trying it out with the stock hammer can't hurt and I am sure you have the parts to just drop in and test :D
Yup, hammer is one of my early R&D testers made of Acetal at @ 28 grams ( Nylon is far better & whats used in production ones )
Am aware and figuring not a lot is going to be gained efficiency wise being the LW hammers show good results generally. THIS IS A TEST that ABSOLUTELY kills hammer bounce ... so data gained does shed some light on just how well they are performing ???
As too cocking effort, it is no big deal being already quite smooth. Use of the OEM 6# spring was always ideal with the light hammers. Dwell lost to less strike because hammer springs influence missing is indeed correct ;)
Tho not convinced a stronger spring throwing the hammer at valve harder is going to hurt a thing, but only increase lift & dwell incrementally which is what I'm after.
* Do feel STRONGLY that valve dwell can be less simply because the poppet valve DOES NOT CARRY THE WEIGHT of the preloaded hammer as much when closing. The Elastic collision has both hammer and stem bounce off one another anyways & with no spring energy holding hammer against poppet stem basically predisposing closing poppet to carry the hammer with it we should gain closing speed.
Think this could be HUGE especially in cases where Heavy hammers and springs typical to Big bore and High power pneumatic guns.
End of the day for the Test this is .... we are getting ZERO bounce as we play around which for me at least opens a whole new way perhaps of addressing the porting of valves and setting up springs etc .. within them.
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Motorhead, I see you see the lower ES as well, same as what I found in mine.
It's such a "simple" mode really, and allows to play around with hammer weight/springs without having to account for bounce.
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Scott, how big of a gap are you leaving? I found out that increasing the gap actually increased the velocity. http://www.gatewaytoairguns.org/GTA/index.php?topic=100123.msg939510#msg939510 (http://www.gatewaytoairguns.org/GTA/index.php?topic=100123.msg939510#msg939510) You may want to give it a try.
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Scott, how big of a gap are you leaving? I found out that increasing the gap actually increased the velocity. http://www.gatewaytoairguns.org/GTA/index.php?topic=100123.msg939510#msg939510 (http://www.gatewaytoairguns.org/GTA/index.php?topic=100123.msg939510#msg939510) You may want to give it a try.
Only testing done was with a gap of @ .030/.040" .... have to try more it would seem.
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I tried this idea on a regulated PCP today, and it went very well.... The gun was my QB79 Ninja, regulated at 1200 psi, that shoots 25 FPE with 15.9 gr. JSB Exacts.... I used two 1.75" x 0.040" springs on a 7/32" guide, giving a total spring length of 3.4" and a rate of about 7 lb/in.... I tried three different amounts of preload, 0.70", 0.80", and 0.90", and adjusted the position of the end of the guide from 1 turn of compression against the hammer to 3 turns of gap (24 TPI), so the total range of adjustment in position was 0.167".... Here is what happened....
(http://i378.photobucket.com/albums/oo221/rsterne/QB%20on%20HPA/QB%20Ninja%20Preloaded%20Guide_zpsscalhmjr.jpg) (http://s378.photobucket.com/user/rsterne/media/QB%20on%20HPA/QB%20Ninja%20Preloaded%20Guide_zpsscalhmjr.jpg.html)
You can see that the maximum velocity this gun can reach is ~850 fps with these pellets.... As I increased the preload, the velocity at any given gap between the end of the guide and hammer increased, as expected.... For instance, with 2 turns of gap (0.084"), the velocity with 0.70" of preload in the spring was 760 fps, with 0.80" of preload it was 790 fps, and with 0.90" of preload it was 820 fps.... With the guide just touching the inside of the hammer, the velocities were 836, 840, and 845 fps.... and with the guide pushing on the hammer (actual preload on the hammer at rest), the velocity was within 2 fps with all preloads, about 847 fps....
The interesting part of the graph above, is the efficiency curves (the dotted lines).... With the guide pushing on the hammer, the efficiency was horrible, about 0.55 FPE/CI.... I think what is happening is that the large amount of preload is slowing the closing of the valve, and causing what amounts to a dump shot.... Once the guide is clear of the hammer, however, the efficiency is greatly improved.... With it just touching, it is 1.15 FPE/CI, which is about the same as I used to get on the knee of the curve with the original setup.... As soon as there is a gap, and it doesn't need to be much, just 1 turn (0.042"), the efficiency is great, between 1.27 - 1.32 FPE/CI at all preloads.... The efficiency at any given velocity is slightly better with more preload, which to get that same velocity requires more gap between the hammer and the guide....
I ended up using the 0.90" preload and 1/2 turn of gap (just 0.020") between the end of the guide and the inside of the hammer.... This gave me 843 fps (25.1 FPE) at an efficiency of 1.27 FPE/CI, which is better than I had with the original setup.... The ES, at 10 fps over a 20 shot string, is a bit better, and the SD is definitely better than before, with by far the majority of shots being within about 4-5 fps, with only the occasional high or low shot.... possibly due to differences in individual pellet weight or fit.... All in all, I am very pleased with the results.... The report, BTW, is slightly quieter than before, with NO audible hammer bounce.... It would appear that this setup does, indeed eliminate hammer bounce.... I think the efficiency graph, being so flat once there is a gap, proves that point....
Bob
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Bob,
Very useful data, and if imitation is the sincerest form of flattery, then I hope you don't mind being flattered. One question: When you refer to the spring guide just touching the hammer, or one turn of clearance, etc, that is when the hammer is in the un-cocked position, with the hammer resting against the valve stem, correct?
Your idea is great, but I really wanted to use it with a cocking rod on a project that I am deep into right now. And, I think I have figured out a way to use your pre-loaded spring guide in combination with a cocking rod.
Take a look at the 2 pictures, one un-cocked, and one cocked. The spring guide/preload rod is thinwalled, hard, stainless steel tubing, threaded at both ends per your design. The center cocking rod is a hard stainless steel rod passing through the I.D. of the preload tube. This might require a combination of metric and SAE threads, but suitable sizes are available. Despite the minimal clearance between the cocking rod the pre-load tube I.D. , the sliding action between the two components only occurs at the very end of the hammer travel when the hammer is actually opening the valve. Some of my spacing's might not be drawn exactly right, but the concept is there.
It ought to work.
Lloyd
(http://i226.photobucket.com/albums/dd79/loyd500/Miscellaneous%20pics/NBHammer-1_zpsgvhzcvbv.jpg) (http://s226.photobucket.com/user/loyd500/media/Miscellaneous%20pics/NBHammer-1_zpsgvhzcvbv.jpg.html)
(http://i226.photobucket.com/albums/dd79/loyd500/Miscellaneous%20pics/NBHammer-2_zpsgnjxga4t.jpg) (http://s226.photobucket.com/user/loyd500/media/Miscellaneous%20pics/NBHammer-2_zpsgnjxga4t.jpg.html)
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Lloyd, I think you can simplify by moving the stop "blue" to the rear of the spring instead. That way you dont need to sleave the cocking rod.
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Lloyd, I think you can simplify by moving the stop "blue" to the rear of the spring instead. That way you dont need to sleave the cocking rod.
Tomg,
I don't think I follow you. If I eliminate the sleeve, then the de-bounce scheme won't work, and that is the purpose of this exercise.
The cocking rod pulls the hammer back and compresses the spring until the hammer latches on the sear. When the sear releases the hammer, the spring pushes the end of the sleeve against the hammer and the everything moves as a single assembly until the sleeve is stopped by the large blue endcap. At that point, the hammer keeps moving forward to strike the valve stem, but the spring and sleeve are allowed to establish an air gap between themselves and the hammer. Then when the hammer bounces back from the valve stem, the air gap is what changes the dynamics, and attenuates the hammer bounce in such a way that the hammer cannot re-open the valve. The two individual pieces, the cocking rod (green) and the spring guide/sleeve (black) are both needed for the hammer de-bounce scheme to work.
Lloyd
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First of all, Scott, let me apologize for not commenting last night, it was late and I just wanted to get my results up before I hit the sack.... Your setup is beautiful.... clean, light and attractive, and apparently does the job.... You will likely find you need to increase the total hammer energy stored in the spring, because not all of it ends up doing useful work at the valve.... If cocking force is not an issue, you can likely just preload the original spring, keeping it just clear of the hammer.... Once you find enough preload to make up for the loss in energy, the system should work great, providing you can still cock the gun without hitting coil bind.... The maximum cocking force will, of course, be greater by the amount of preload if you use the same spring....
I think a better way is to use a longer, lighter spring with significant preload.... If the preload is minimal, the hammer may still compress it when flung back by the valve.... I don't know when that occurs, but a WAG tells me that somewhere around 1/3 of the maximum force for preload is the minimum.... it may need to be greater, up to 1/2.... The greater the percentage of preload, the longer the spring has to be, and that means more room required.... It will take a lot more experimenting to find all the working parameters, but one thing you and I certainly agree on.... It would appear that the Stopping Spring Guide (SSG) can prevent hammer bounce, saving air, reducing report, and as a side benefit it may reduce the ES....
Lloyd, as usual, the best way to get you to find a solution to a problem is to tell you I don't have one.... *LOL*.... The concentric guide tube is brilliant.... I notice that you are using a hollow adjusting bolt (purple) to allow you a place to hide the longer spring required.... I have a partial version of that in my Monocoque PCP, the 2" bolt is drilled in 1/2", but it could just as easily be drilled 2", with only the head left as a spring seat.... I don't know what the required space is between the end of the guide and the inside of the hammer is at rest (uncocked), but it appears it can be minimal and still provide the anti-bounce effect.... The preload is the "coarse" adjustment, putting the velocity in the range you want, and then the gap is the "fine" adjustment, allow you to fine tune the balance between velocity and efficiency.... The two work in concert, as shown in the graph above, which should give guys the idea of what is happening....
Go to it, guys !!!.... It is exciting to see something new capturing the imagination of the developers.... I can see this may have a great application when combined with a balanced valve, preventing the hammer from reopening that (much easier to re-open) design.... When combined with the much lighter hammer and springs usable once the huge opening forces are eliminated, this could truly revolutionize PCPs.... I can see something like the Cothran valve but without the added complication of the "leaky check valve" rod inside the valve stem, for instance, which is there to prevent the hammer from re-opening the valve and wasting air.... The mind boggles at the possibilities.... it is KEWL to be a part of that.... You like the Acronym SSG?....
Bob
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Bob, if you like SSG, I am with it too. ;)
This is fun, ......this ..... maybe you could call it .....cooperative competitiveness. Good people on a good project. What is better than that? ;D
Bob, I hope I get the spring size correct the first time because I don't really want to make these parts a third time, LOL. I understand the concept of the long length of preload on a long fairly soft spring. The preload turns it into more of a short stiff spring without the final cocking effort going sky high. A spring that goes from 5 pounds preload to 15 pounds when cocked yields the same amount of energy as a spring that goes from 0 pounds to 20 pounds.
It seems like the clearance adjustment between the SSG rod and the hammer isn't super critical so long as you have at least .030" or so of clearance???
One thing which I guess I will find out, is how much of a thump is there when the SSG hits its travel limit when the gun is fired? Do you or Scott think it is enough to cause accuracy issues? I would think that choosing a proper bumper material to arrest the spring could be helpful. Maybe some of the ISOLOSS material?
Scott, I like the way you incorporated the plastic alignment and anti-friction guides in your build. Those details really make a difference in consistency.
Lloyd
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Bob, if you like SSG, I am with it too. ;)
One thing which I guess I will find out, is how much of a thump is there when the SSG hits its travel limit when the gun is fired? Do you or Scott think it is enough to cause accuracy issues? I would think that choosing a proper bumper material to arrest the spring could be helpful. Maybe some of the ISOLOSS material?
Scott, I like the way you incorporated the plastic alignment and anti-friction guides in your build. Those details really make a difference in consistency.
Lloyd
Lloyd,
Early in this discussion had made note of using a "Spoke" or similar minimal mass rod to retain the fixed length. This was already in my mind addressing rapid deceleration of the limit rod creating a BUMP.
* Test is simple enough ... manually pull out the rod to an @ distance it is when action is cocked and LET IT GO :o ... what vibration it creates is ALL you should feel doing so & very telling of this sudden collision. Then playing with bumpers and there effectiveness ;)
Indeed once hammers in GLIDE mode upon striking poppet ANY & ALL sources of drag/friction OTHER THAN resistance to opening the poppet valve will rear there ugly head and consistency will likely suffer.
We having FUN yet ;D ;D
Scott
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Thank you Bob ....
Lazy New Years day so why not fiddle some ;D
Test platform the .22 Marauder w/Reg & Bottle. Before doing this was at 865 fps with 18.1 jsb.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
First pictures the parts made up after thinking of a simple way to set up, be 100% reversible without being getto with the actual modification.
(http://i1320.photobucket.com/albums/u532/scott_schneider1/DSCF9915_zpsumomw8jh.jpg)
Used a 8-32 threaded blind nut and long SS 8-32 screw. Machined up a Delrin AF collar to be the seat for spring & center it within hammer bore. Then a 3/8-24 threaded guide that screws into back of velocity adjuster cap.
* the long screw into the blind nut adjusts over all length between the two, keeps the assembly minimally invasive when cocked and just looks clean ;)
Scott -
Where did you get these parts? Can you list them in a bit more detail?
Thanks.
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Thank you Bob ....
Lazy New Years day so why not fiddle some ;D
Test platform the .22 Marauder w/Reg & Bottle. Before doing this was at 865 fps with 18.1 jsb.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
First pictures the parts made up after thinking of a simple way to set up, be 100% reversible without being getto with the actual modification.
Used a 8-32 threaded blind nut and long SS 8-32 screw. Machined up a Delrin AF collar to be the seat for spring & center it within hammer bore. Then a 3/8-24 threaded guide that screws into back of velocity adjuster cap.
* the long screw into the blind nut adjusts over all length between the two, keeps the assembly minimally invasive when cocked and just looks clean ;)
Scott -
Where did you get these parts? Can you list them in a bit more detail?
Thanks.
Your talking with a Pack Rat !!
Long screw was from a weedeater carb to manifold ( Had a few of these for 30+ years in a screw bin ) Where exactly from have no ideal any longer.
Blind nut is from a Glass/Ceramic knob used on furniture.
Other 2 Delrin AF parts were manufactured in house.
Whats was shown is yesterdays TRIAL parts to get an operational stop rod w/o a lot of fancy stuff happening.
Sense then already REDID the spring holder ( Blind nut part ) to one being made of Billet aluminum and a lot stronger !! Frankly think the real soft thin material blind nut used will get the head torn right off from the repeat hammering of stopping the spring and rods motion.
Shared was in reality TEST PARTS for proof of concept testing only.
Bearing/guide on rear of velocity adjuster can be made far less obtrusive as will likely ROD used be reconfigured in such a way to loose mass further reducing vibration influences.
R&D guys .... think outside the box and create some unique solutions ;)
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I thought this may help with the guess work. Even though I still believe a 30 cent short stiff spring will accomplish the same thing.
Guys we are getting over complicated even though I feel as if this is a think tank. Now, since we all know that negative preload (stiff spring or loaded spring) increases shot count and lowers ES, we (you all) should also consider porting since we "all" know that this helps closing the poppet (reducing dwell).
Most or all of you experimented with porting with "the old" hammer powerplant of using preload.
hopefully this spreadsheet will take the guess work out out of Bobs design when building your own. :D
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I thought this may help with the guess work. Even though I still believe a 30 cent short stiff spring will accomplish the same thing.
Guys we are getting over complicated even though I feel as if this is a think tank. Now, since we all know that negative preload (stiff spring or loaded spring) increases shot count and lowers ES, we (you all) should also consider porting since we "all" know that this helps closing the poppet (reducing dwell).
Most or all of you experimented with porting with "the old" hammer powerplant of using preload.
hopefully this spreadsheet will take the guess work out out of Bobs design when building your own. :D
Personally feel your MISSING a point Bob spelled out early on .... With spring under preload it becomes for sake of hammer bounce a non yielding surface hammer simply can not rebound off of.
A heavier spring in a relaxed state as your talking, has resiliency and yield to compression motion.
It will indeed absorb some hammer motion as poppet throws hammer against it and then rebound the hammer towards poppet again. LESS for sure than a conventional pre-loaded set up does, but no where as controlled rebound free "DEAD" as idea we're exploring within this thread.
IMO,
Scott
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Great Work Guys, ;)
Bob would you mind showing some pictures of your QB SSG?
Given the efficiency of your prior set-up (1.07%) vs. the SSG (1.27%) or +18.7%, do you think it is worth the labor involved? You got almost 80 shots previously, I guess that turns out to be about 94 shots afterwards :D --------> OK, I'm sold ;)
It's fun to watch Bob, Motorhead and lloyd's brains in action, the masses (me) find this very Cool... Happy New Year !! 8) Keep shooten the can down the road............. Kirk
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The spreadsheet is only showing what your doing and helping with the thread. That was the intention.
It was meant to help you .!"x).
Whatever.... :P
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Hey Shorty,
What or Who are you talking about? ??? Let's keep the Grinch out of this thread!! ;)
Kirk
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Okay guys, try not to laugh at my diagram/idea here, but... :D I don't have any cad software, so this was done with paint, and it isn't to scale. It is with an AT-44 hammer, since that is all I have any hands on with. This is the gist of what I was talking about when I said some variation of a damped hammer. I hope this makes sense :-[
(http://i644.photobucket.com/albums/uu168/tiltedmonkey/DAMPED%20HAMMER%20AT-44.jpg) (http://s644.photobucket.com/user/tiltedmonkey/media/DAMPED%20HAMMER%20AT-44.jpg.html)
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Yesterday and today I worked on fitting an SSG to my QB Ninja.... The gun is regulated at 1200 psi, and is modified to cock-on-open.... The best previous tune delivered 81 shots at 850 fps from a 13 CI tank filled to 3000 psi and refilled at 1100 psi.... For the preloaded spring for my "Stopped Spring Guide" modification I used two 1.75" x 0.040" wire springs on a single 7/32" guide, with 10-32 nuts both ends (the front one turned to fit inside the hammer).... The adjusting bolt is a 3/8" - 24 NF bolt drilled for the guide, and it is carried in a short piece of aluminum which is bolted inside the QB tube.... Here is the previous cock-on-open RVA, and the new SSG setup, positioned relative to each other the way they sit inside the tube....
(http://i378.photobucket.com/albums/oo221/rsterne/QB%20on%20HPA/SSG%20and%20Original%20RVA_zps4u7cekdv.jpg) (http://s378.photobucket.com/user/rsterne/media/QB%20on%20HPA/SSG%20and%20Original%20RVA_zps4u7cekdv.jpg.html)
In the uncocked position, you will notice that the end of the guide is basically flush with the end of the tube, but of course it sticks out when cocked.... I cured that later, as you will see below.... There are two screws to mount the aluminum block in the tube, a short one on the bottom and a long one on top, that goes through the breech and holds it down.... Since I didn't need the back part of the bolt that normally moves the pin for the cocking block, I cut it off flush with the back of the setscrew that holds the bolt handle, and the hole for the top screw for the SSG is immediately behind the bolt when fully back.... You can see the relative positions of the parts in the photo below....
(http://i378.photobucket.com/albums/oo221/rsterne/QB%20on%20HPA/SSG%20Assembly%20Showing%20Position_zpsqmfekpgb.jpg) (http://s378.photobucket.com/user/rsterne/media/QB%20on%20HPA/SSG%20Assembly%20Showing%20Position_zpsqmfekpgb.jpg.html)
In order to cover the back of the breech, I made a special bolt from a short metric flat-head screw by turning the head to 1/4" OD and thinning it slightly.... and then milled a recess in the breech cap to allow it to sit below flush, as below....
(http://i378.photobucket.com/albums/oo221/rsterne/QB%20on%20HPA/Breech%20Cap%20Screw_zpsp7tam7lq.jpg) (http://s378.photobucket.com/user/rsterne/media/QB%20on%20HPA/Breech%20Cap%20Screw_zpsp7tam7lq.jpg.html)
The bottom SSG mounting screw interfered with the trigger, so I used a low profile SHCS and counterbored a recess in the trigger as shown to miss it....
(http://i378.photobucket.com/albums/oo221/rsterne/QB%20on%20HPA/Trigger%20Recess%20for%20Screw_zpsfbziip6m.jpg) (http://s378.photobucket.com/user/rsterne/media/QB%20on%20HPA/Trigger%20Recess%20for%20Screw_zpsfbziip6m.jpg.html)
Since when cocked the guide and nuts stick out the back of the tube, and I needed something to mount the back of the trigger into, I made a cover from aluminum as shown below.... It is tapped for a 10-32 screw to attach the back of the trigger through the original hole in the back of the tube.... It does double duty to prevent the gap adjusting bolt from rotating as well.... The lip that sticks forward inside the tube has a flat milled on the top that just clears the flat on the bolt, so that once inserted the bolt can no longer rotate.... You do the adjustment with a socket wrench and then slide the cap in and bolt the trigger in place and the adjuster can no longer rotate....
(http://i378.photobucket.com/albums/oo221/rsterne/QB%20on%20HPA/SSG%20Cocked%20with%20Cover_zpsinu4yshn.jpg) (http://s378.photobucket.com/user/rsterne/media/QB%20on%20HPA/SSG%20Cocked%20with%20Cover_zpsinu4yshn.jpg.html)
When the gun is reassembled, the only change in appearance is the extended aluminum cap on the back of the tube, and the head of the upper screw on top of the breech under the scope.... It doesn't interfere with my scope rings, although something to consider if yours were in a different place....
(http://i378.photobucket.com/albums/oo221/rsterne/QB%20on%20HPA/QB%20with%20SSG_zps9zlr0bfz.jpg) (http://s378.photobucket.com/user/rsterne/media/QB%20on%20HPA/QB%20with%20SSG_zps9zlr0bfz.jpg.html)
During final tuning today I found a few more fps, and the gun now averages 851 fps (25.6 FPE) with the SSG one turn out from touching the hammer (0.042").... The ES is narrower than before (it was 12), only 8 fps over the first 86 shots of a 90 shot string down to 1100 psi.... Shot 91 was 838 fps.... This SSG gave me a gain of 9 shots over the previous arrangement (11%), increasing the efficiency to a pretty stunning 1.36 FPE/CI.... Here is the shot string....
(http://i378.photobucket.com/albums/oo221/rsterne/QB%20on%20HPA/QB%20Ninja%20with%20SSG_zpsnojreotf.jpg) (http://s378.photobucket.com/user/rsterne/media/QB%20on%20HPA/QB%20Ninja%20with%20SSG_zpsnojreotf.jpg.html)
I am now a firm believer in the SSG system as having the potential to increase the efficiency of a PCP, even a regulated one that was already pretty good.... If you can hear the telltale BUURRRPPPP of hammer bounce in you gun, and getting rid of it has been a problem for you, considering this modification could be the way to go....
Bob
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Thanks Bob,
That's a Helll of a lot of work for 10 shots ;) and a lower ES, but pretty darn Cool 8).
Again, thanks for sharing/helping............. Kirk
Did you use a mill to help make the Extended aluminum cap?
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Yep, used my milling attachment on my lathe to drill the hole and mill off the side of the tab.... BTW, since when didn't it make sense to try and improve something?.... *LOL*.... Besides, nobody pays me for my time, so I can use it as I please.... *grin*.... I'm not twisting anyone's arm to do this, just showing what is possible.... and trying to figure out (and explain) why....
Bob
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Rallyshark.... I understand your drawing, but I remain unsure of the way this would reduce hammer bounce.... You said the oil should be "thick enough to not give on hammer acceleration but thin enough to give on valve strike".... I guess you are trying to accomplish a "dead blow" hammer?.... My thought is that expending energy at the instant the hammer strikes the valve to displace oil would, by definition I would think, require more hammer strike to open the valve to the same degree.... I don't think the hammer bounces OFF the valve stem, which is what your idea would help prevent.... It should insure that the hammer travels WITH the valve stem, but I think if does that already....
Hammer bounce, as I understand it, is the valve stem imparting energy to the hammer on the return trip (valve closing).... and then the hammer in turn causing that energy to be stored in the hammer spring.... Once the hammer stops, that stored energy accelerates the hammer forward again, with one of two results.... the valve either opens (and wastes air), or it doesn't.... Light hammers store less energy, as do stiff springs with a gap between the hammer (at rest against the valve stem).... The concept I am trying to achieve here with the SSG, is that the spring is preloaded to the point that the hammer energy imparted by the closing valve stem cannot deflect the spring, so it can't store energy to be returned to the valve and re-open it....
Bob
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Capisce, we appreciate your efforts!! 8)
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Bit more fiddling tonight .... having not crunched efficiency numbers yet being we're still changing small details, air use is appearing to be SUBSTANTIALLY less as shot after shot gets taken & gauge does not move lower nearly as quick.
Installed the beefed up spring holder at end of limit screw adding an additional 3/16" of preload taking the 6# oem hammer spring to within 1/8" travel of coil bind. Velocity with 18.1's now maxed out at 835 fps.
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Rallyshark,
For just using Paint, that is a darn nice concept drawing of your damped hammer.I know that took a lot of time to do.
I am still a little fuzzy on the mechanics of the setup, though. Please see if I have an understanding: With the initial hard hit of the hammer against the valve stem, the oil is thick enough that it can't flow fast enough and it kind of stays solid and the big hit takes place. But on the rebound, the velocity is lower, and oil flows thru an orifice, attenuating the impact such that the valve is not opened a second time.
Is that close?
Lloyd
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Rallyshark,
For just using Paint, that is a darn nice concept drawing of your damped hammer.I know that took a lot of time to do.
I am still a little fuzzy on the mechanics of the setup, though. Please see if I have an understanding: With the initial hard hit of the hammer against the valve stem, the oil is thick enough that it can't flow fast enough and it kind of stays solid and the big hit takes place. But on the rebound, the velocity is lower, and oil flows thru an orifice, attenuating the impact such that the valve is not opened a second time.
Is that close?
Lloyd
Lloyd,
Thanks, but it only took me about 15 or 20 minutes to do that in paint. I did it by eye, and wasn't trying to match everything by the numbers, so it really wasn't that hard. I tend to do better by eye, instead of exact measurements. I'm not patient enough to do real cad, and I haven't been able to get Sketchup to work on Windows 8. You are very close to understanding what i'm talking about, and you have the right idea. The oil filled shock is a stolen straight from an RC car, so it is quite easily "tuned" to your needs. The shock won't give much on the hammer acceleration prior to initial strike of the valve. The sharp impact with the valve stem will cause it to give some, but with the light spring on the shock, it won't extend back out fast enough to cause it to bounce and reopen the valve any. I guess it would be somewhere between a strong short spring "throwing" the hammer at the valve and a conventional setup. Bob is sort of right about a dead blow hammer too. The difference being that the hammer/spring will return to full length, UNLESS resting on the valve stem. The idea being you won't have to use a really heavy spring, but maybe one only slightly heavier than a standard spring. The hammer/spring will not extend to full length fast enough for the valve stem returning to impart any energy on the hammer spring, and thus the hammer spring cannot re-open the valve. Essentially, the shock portion of the hammer is "slow". Yes it is a spring, but it compresses/extends slower than a normal spring. The very nature of a damper is to prevent bouncing, which, in this case will prevent it from bouncing after the valve returns. I'm sorry if I'm not explaining this well. Things always make more sense in my head than they do when I try to put it into words :(
You would want it adjusted so that the shock/shock spring are slightly compressed and resting on the valve stem when not cocked.
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Thanks Kirk, I'll keep the grinch locked up.
Since we all agree the the negative preload is the most influencing, both short spring and SSG, In my head, I am still trying to understand if the SSG rebounds the hammer (after it has struck the valve stem) with more or less force than the short stiff spring.
Based on this site of elastic collision (http://www.webassign.net/question_assets/tamucalcphysmechl1/lab_7/manual.html (http://www.webassign.net/question_assets/tamucalcphysmechl1/lab_7/manual.html)):
There was a nice experiment (better than me running into a wall ;D). I took a steel ball and dropped the steel ball onto the back of my work bench vise , then put a 7 lb spring clamped into the vise and dropped the ball on it.
The steel ball bounced off the back of the work bench higher and with great force than when bounced on the spring.
So, it "appears" that steel hitting steel is more elastic and the spring absorbs the energy which in turn reduces the amount of rebound. But we all knew that already.
Well,
I started thinking if the SSG can be improved further. I took a small thin piece of leather (shoe tongue) and placed it on the back of the work bench vise and dropped the ball on that. The bounce back was nearly 0 to nothing.
With that being said, a small piece of dampening material placed in the hammer between the SSG and hammer may reduce that elastic/in-elastic collision to a point of nonexistence.
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Glad to read many of us are dwelling on this.
I too in the last days was thinking of a K.I.S.S. damper to further stop kinetic energy transfer once shot has happened.
Tho thoughts not shared previous, was thinking a SOFT silicone 0-ring resting on the end of spring hat within hammer bore.
O-ring sits on a shoulder to hold it having say .015 . .020" of it's height above shoulder it sits on.
When action is cocked the pressure of hammer spring on the hammer simply crushes o-ring that .020" or so bottoming out the spring hat to hammer connection. as hammer is released this connection crushing o-ring remains tight.
ONLY when limiter rod bottoms out and hammer free travels forward is the small crush on o-ring relaxed.
* Now as poppet sends hammer back at the spring does this o-ring once again see compression forces ... which it promptly absorbs stopping hammer from compressing the spring again.
Very KISS ( Keep it simple stupid ) solution if rebound energy transfer is wanting / needing to be mitigated ???
Scott
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OK, call me neurotic ???
Went over to the lathe and made up another spring hat for end of stop rod.
* Note length is only such because i am wanting more spring preload greater than end caps adjustment can give getting OEM length spring near coil bind.
So here the part as talked about above. O-ring is UNDER the diameter of spring/hat so there is no drag by it being there, no seal made creating suction or such issue having drag.
Groove or shoulder O-ring gets Stretched over done at an angle similar to a spring guns piston holding seal.
The back wedge angle keeps the o-ring wedged in preventing the slap of rod stopping & spitting it off the end !!
(http://i1320.photobucket.com/albums/u532/scott_schneider1/DSCF9921_zpsmpaazn2a.jpg)
Also make note of the bevels at the hats O.D. ;) this to counter drag as piston rocks or stop rod is off center line.
Low drag HERE is paramount if hammer it to continue independant w/o any drag created by the Spring / Hat parts.
O-ring once stretched over the wedge shaped nub on hammer end of the hat.
(http://i1320.photobucket.com/albums/u532/scott_schneider1/DSCF9922_zpsmnddec2a.jpg)
Next shown the COMPRESSION & DAMPING idea of o-ring compression once hammer is drawn against it while cocking.
(http://i1320.photobucket.com/albums/u532/scott_schneider1/DSCF9924_zpswrrmcrgo.jpg)
Gap shown compresses flat with a few pound pressure, but in theory softly impacted by the rebounding hammer should stop it dead in it's tracks never coming close to getting an elastic collision bounce off end of the stop rod & spring ???
Theory and Testing .... what R&D is ;)
Even if the effect is minimal, presents of the o-ring at this location effects NOTHING else in the system ;)
Scott
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I like the damping just because anything that reduces vibration in the shot cycle is a plus in my book... the speed of sound being high in dense material means it can contribute to barrel harmonics... but it would probably have to be a dense plastic to hold up... leather would wear to quick I think.
started to write about a captive two piece hammer and sleeve rear cocker but pulled it down...just did not have the concentration for a couple hrs. drawing and trying to explain. I do think that it could work well but the added complexity gives it more ways to possible cause a bit of E.S. spread..? But I just like rear cockers...
Me I keep thinking of a double reg'd system and a piloted blow open balanced valve ; small dump valve provides overpressure that bleeds off controlling timing of the balanced valve... ??? ::).
The goal being taking as much of the vibration out of the shot cycle as possible and more important the most consistent charge release you can manage.
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Great stuff here!
Was thinking (I know) it might make sense to integrate the whole thing into the hammer itself. The Spring guide would run all the way through the hammer and preload the spring against the hammer body itself, with the final gap being between the back end of the guide and the rear cap.
When cocked, the hammer would slide along the guide, compressing the spring, with the extra guide extending in front of the hammer body, so that nothing has to stick out the back of the gun. When fired, the hammer slides along the guide until it hits the front of the guide, then carries everything with it to impact the valve stem.
No ugly parts sticking out the back of the gun, no energy wasted accelerating mass that won't be used to open the valve....just a thought.
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Great stuff here!
Was thinking (I know) it might make sense to integrate the whole thing into the hammer itself. The Spring guide would run all the way through the hammer and preload the spring against the hammer body itself, with the final gap being between the back end of the guide and the rear cap.
When cocked, the hammer would slide along the guide, compressing the spring, with the extra guide extending in front of the hammer body, so that nothing has to stick out the back of the gun. When fired, the hammer slides along the guide until it hits the front of the guide, then carries everything with it to impact the valve stem.
No ugly parts sticking out the back of the gun, no energy wasted accelerating mass that won't be used to open the valve....just a thought.
Only PCP that comes to mind using an Off Center poppet is Air Arms ... This would allow a guided stem & stop ideal to get played with on a pre-existing platform.
Sadly centered poppets striking hammer center are troublesome if I understand idea correctly ?
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Great stuff here!
Was thinking (I know) it might make sense to integrate the whole thing into the hammer itself. The Spring guide would run all the way through the hammer and preload the spring against the hammer body itself, with the final gap being between the back end of the guide and the rear cap.
When cocked, the hammer would slide along the guide, compressing the spring, with the extra guide extending in front of the hammer body, so that nothing has to stick out the back of the gun. When fired, the hammer slides along the guide until it hits the front of the guide, then carries everything with it to impact the valve stem.
No ugly parts sticking out the back of the gun, no energy wasted accelerating mass that won't be used to open the valve....just a thought.
Only PCP that comes to mind using an Off Center poppet is Air Arms ... This would allow a guided stem & stop ideal to get played with on a pre-existing platform.
Sadly centered poppets striking hammer center are troublesome if I understand idea correctly ?
Not really a problem, just make the front of the spring guide similar to the mrod striker plate, just not threaded to the hammer body.
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Stopped Spring Guide ,Slap Shot Goal/guide... hmmm looks like the Geat White North made it into the name.. ;)
Thanks Bob for sharing... much inspiration with built fact...that works and very well...
MotorHead well wow on being able to throw it together... inventive tinkering for sure... me I was just proud of my hardware store brass t_ports for my pumpers...
I wonder how many of the Big Builders are secretly monitoring the Gateway for the innovation shown by the folks here...
You guys are the Wildcatters of Air (well helium also)...
Is really is great being able to watch the work happening and hearing the discussion as it does...
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All sorts of good thinking going on here, I feel lucky to be keen on tinkering with PCPs during a time of so much user-friendly innovation.
Bit puzzled by shorty's 'experiment' though... puzzled enough that I put a hammer spring in my Record bench vise and dropped a tiny hammer on it (the handle helping me to loosely retain control, maintaining the hammer on top of the spring). It bounced back up about 1/3 as far as I dropped it and kept on bouncing several times, lower each time. Then I took the spring out and closed the vise and dropped the hammer again. Clunk. About 1mm bounce at most, once only.
So my result is exactly the opposite of what he's claimed several posts back. Either he's 'misstating' his observations for some unknown reason, or my hammer and spring and vise are somehow magically doing the opposite of what they'd do for other folk. It'd be a bit of a head-scratcher if it weren't for rsterne's results being charted so very clearly, with efficiency going WAY UP when the SSG is used and tuned correctly. Results in actual airgun application seem to bear out what this simple experiment of shorty's demonstrates on my iron vise. Thanks for the reassurance Bob, unintentional though it may be. I'll be giving this thing a try sooner or later in one or more of my airguns.
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Gerard,
I had to go try it with a hammer after your post. Got the same results as you. :D
I then did it with the steel ball again and got the opposite results again. >:(
What the heck ?
Truley, I am not trying to be misleading.
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I think that the O-ring at the back end of the (solid steel) spring guide provides a damping action on the collision of the hammer with the guide when launched back by the valve.... As Lloyd mentioned, when the hammer hits the guide, it transfers part of its momentum to the guide, which is actually then in a balanced state (both are preloaded) between the spring pushing it towards the valve and the O-ring pushing it the other way.... When the hammer strikes the guide, it likely moves a few thousandths of an inch, flexing the O-ring and dissipating energy.... To do that, however, as Lloyd mentions, it has to waste some energy moving the guide....
IMO, if a resilient (ie springy) cushion is used between the hammer and the front end of the guide, it can act like a spring (albeit a very stiff one).... Since during the hammer's round trip with the valve it is NOT compressed, it only takes a very small force to compress it, and it then stores energy (like a very stiff uncompressed spring), and can return it to the hammer again.... If we were seeing hammer bounce, then it might be necessary to go looking for a solution for that.... either in the form of a fluid damper, or a resilient cushion, inside the hammer.... but are we looking for a solution to a problem we just cured?....
bstaley, if I understand your idea correctly, the front of the guide hits the stem, it is sliding through a hole in the front of the hammer, with a stop on the guide on the front side of the hammer, and with the spring inside the hammer.... At rest there is a gap between the back end of the guide and the rear cap (or the front of the guide and the stem, take your pick).... The entire hammer, guide, and spring assembly is rattling around loose when uncocked, by the amount of the gap.... The hole in the hammer which the guide slides in, has to be long enough to keep the guide straight, relative to the hammer.... When you cock the gun, you slide the hammer back, which pushes on the spring, pushing the guide back to stop against the rear cap and the spring is then compressed until the hammer latches on the sear.... The guide is sticking a long ways out of the front of the hammer (whatever the hammer stroke is), and is just clear of the valve stem.... When you fire, the hammer slides along the guide, hits the front stop (integral with the gude), slows down because it has to now accelerate the mass of the guide (conservation of momentum), and the guide/hammer/spring assembly then strikes the valve stem.... with the front of the guide actually doing the striking.... The valve opens and closes, and on closing throws the entire guide/hammer/spring assembly back until the guide hits the rear cap.... It stops, and the preload on the spring arrests the hammer, just as in the SSG, and the assembly rattles around until it comes to rest (just like the hammer in the SSG)....
You state that there are no "ugly parts" sticking out the back of the gun (there doesn't have to be anyway, see my solution on the QB).... and indeed you should save some overall length.... Your gap between the back of the valve stem and the inside of the rear cap must be the length of the preloaded spring, plus the thickness of the hammer the guide passes through, plus the end stops on the guide, plus the gap.... On the SSG, the guide when uncocked is the length of the preloaded spring, plus the end stops, then add the thickness of the front of the hammer, plus the gap, but it moves back the distance of the hammer stroke when cocked.... The front of the hammer on the SSG, however, can be thinner because it just has to resist the load of the spring and valve stem strike.... It does not have to be long enough to keep the guide straight.... In the SSG, the guide is kept straight by passing through the gap adjusting bolt.... How much extra hammer length is required to keep the guide straight is the question.... If you had an adjuster for the gap (part of the tuning process), that length would have to be added to the rear cap.... I would guess that the net overall length of the two systems would not be much different....
Gerard, nice to see someone else thought the same thing about shorty's vice and spring experiment, it didn't make sense.... When I read what you wrote, I decided to check it myself.... I got the same results as you did, on the tail of the vice the steel hammer did not bounce very high, and rattled to a stop very quickly.... On the uncompressed spring, it rebounded about a third of the height, and made several bounces, decreasing in height each time, until it stopped.... I then took the spring, installed it on a bolt where I could preload it, and the more preload I added, the less the hammer bounced in distance, and the faster it came to a stop.... This makes perfect sense, as the time it takes for the hammer to bounce once (leaving the spring or vice until striking it again), is governed by the height of the bounce and gravity.... The less the rebound height, the quicker the return trip, and the fewer bounces before the hammer stops moving.... The stiffer the spring (and the steel vice is a VERY stiff spring), the less height, the shorter time for one return trip, and the shorter the total time before the hammer stops bouncing.... A preloaded spring lies in between a loose spring and the steel vice.... and the more preload, the less bounce.... It's a simple experiment that settles the argument completely, IMO.... The less the rebound height, the less energy in the hammer.... I didn't try it with a steel ball....
Bob
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Just did the same "experiment" again. Same results. :D ;D
I gotta hand it to Bob, his SSG system does seem to be better than a short stiff spring with negative preload.
on a side note,
The only reason why I was out at the work bench was because I was making a SSG on the lathe to test out on my marauder. ;)
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If you think about it, increasing the preload on any spring makes it progressively more and more like impacting a steel vice.... I think the AHA moment for me was the PERIOD OF VIBRATION of the hammer decreasing as you increased the preload.... Since the time of flight per bounce is strictly based on how high the hammer bounces (gravity being a constant), it becomes obvious once you try it....
I think you'll like the SSG once you give it a chance, shorty.... Think of it like a spring that takes 5 lbs. to compress the first few thou (as the O-ring relaxes) and then operates like a normal spring.... The more I think about it, the more I like the rear O-ring, even though I originally only put it I there to cushion the blow of the guide when it crashes to a halt.... I use a 90D, BTW, I don't want much give there.... Scott, you can try different ones and let us know what happens.... *grin*
Bob
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Thanks Bob,
I am pretty sure it will out perform the short stiff spring and I will like it.
Just wish I could have completed the SSG without breaking it in half with a little to much turning. Time to start over.
not worthy when you rush something and 2hrs work turns into spaghetti. I started with 1/2 rod.
Sure looks a lot easier using a long bolt.
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My spring guide is just a piece of the appropriate diameter drill rod to fit the inside of the spring (smooth, ground finish), and I thread both ends.... At the front I install the nut with green Loctite, tighten it up against the shoulder or the end of the threads, peen the end over with a hammer so it will NEVER come off, and then machine the nut and the end of the rod to the shape I want to fit inside the hammer.... You end up with something that looks like a long round head screw with threads only at the back end for your preload adjusting nuts....
Bob
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My build was going on the lines of Llyods with a hollow spring guide. I was trying to still have control over the throw but the wall thickness was too thin.
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Just for giggles (and because I LOVE my Sanyo Xacti HD, especially the 300 frames per second video mode!) I set up to try a steel bearing on my vise. Not using the tail section as I only have a 4" Record vise and that part's a bit small to make a good platform for bouncing such things. I made two video clips, one of the ball hitting the hardened jaws with the vise closed, the second with a spring such as I've used in my Brocock Atomic to drive the striker. In the first, I found that indeed a steel ball bearing 21mm in diameter and weighing 39grams (similar to the carved-down striker in my 2240 carbine, quite a bit heavier than the one I turned down in my Atomic) bounces a lot more than an 8oz hammer. Not too surprising considering that all the force of impact is focused in one tiny spot on the sphere, demonstrating maximum rebound potential for the material. A cylinder (similar to an airgun hammer) would be a more fair demonstration (as with the small square hammer I used earlier). Anyway, here's the bearing hitting the vise:
http://www.luthier.ca/other/forum/follow_the_bouncing_ball-vise.MP4 (http://www.luthier.ca/other/forum/follow_the_bouncing_ball-vise.MP4)
Plainly the bearing jumps up quite a bit, then comes down and bounces again, losing energy, then once more off-target and onto the floor. Now the spring:
http://www.luthier.ca/other/forum/follow_the_bouncing_ball-spring.MP4 (http://www.luthier.ca/other/forum/follow_the_bouncing_ball-spring.MP4)
The bearing landed almost perfectly squarely on the end of the spring, which was held firmly in the vise jaws. Not quite perfectly though, so it bounced off at an angle and managed to smack into one of the two LED lamps I had aimed at the experiment, knocking it off by about an inch. The lamp head was almost exactly 12" away from the spring, the same distance I dropped the ball bearing in each of the above tests.
Seems to me these demonstrations provide two useful pieces of information. 1), that hitting a spring (in this case just 27mm of which was able to move) with a steel weight results in that weight being bounced back with close to an order of magnitude greater force than when hitting solid steel, and 2), that spherical strikers are a bad idea.
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Understanding the physics behind the simple device "Newtons Cradle" .... you really need little else to catch a clue that disrupting the energy transfer between any contact breaks the cycle.
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Gerard,
Visual aids are always a help in understanding a concept. Thanks for taking the time to make and post those 2 videos. That rebound from the spring was pretty significant.
Springs, and things that behave like springs, can be helpful tools, or real annoyances. It is hard to make them behave exactly like you want, LOL.
Lloyd
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GREAT VIDEOS, GERARD.... MANY THANKS....
Today I installed an SSG in my 2260 reversed tank HPA.... It previously got 43 shots with JSB 18.1 gr., from 3000 psi down to 1400 averaging 958 fps (37 FPE).... It had a 1.75" x 0.040" wire hammer spring (14 lb/in) and took about 11 lbs. of effort to cock.... This is the gun I'm talking about....
(http://i378.photobucket.com/albums/oo221/rsterne/22%20PCP/2260HPA.jpg) (http://s378.photobucket.com/user/rsterne/media/22%20PCP/2260HPA.jpg.html)
I made a Stopped Spring Guide to carry a 2.00" long 0.040" wire spring (12 lb/in) with about 0.45" of preload (~ 5.5 lbs), and played around with the gap to get the same velocity I had previously.... The gap ended up about 0.040", and the cocking effort was about 12.5 lbs.... The ideal spring would have been slightly longer with a 10 lb/in. rate, but I didn't have one, and as it turned out it doesn't matter.... Even though the maximum cocking force is slightly greater, because it starts out at 5 lbs. instead of less than 2 lbs., it feels smoother and you don't have that sudden increase in force right at the end, that sometimes causes you to not quite cock the gun, which with the MRod magazine causes a double feed.... In all the shots fired during testing (over 200) I never had a mis-feed.... Here is what the old RVA and the new SSG look like....
(http://i378.photobucket.com/albums/oo221/rsterne/22%20PCP/SSG%20for%202260%20HPA_zps52luxxuu.jpg) (http://s378.photobucket.com/user/rsterne/media/22%20PCP/SSG%20for%202260%20HPA_zps52luxxuu.jpg.html)
The old RVA used a floating spring guide that was captive between the spring and the hammer and extended through the adjusting bolt as a cocking indicator.... The 10-32 nut on the back of the new SSG is against a shoulder on the 7/32" guide, so I didn't need a 2nd nut to lock it, I just snugged it up with Loctite.... so the total length when cocked is nearly the same.... During testing springs I noticed that the pressure guage wasn't dropping as fast as before, so I was pretty anxious to check the shot count and efficiency.... Using the same pressure range as before (3000 psi down to 1400) I got 60 shots (instead of 43) averaging 966 fps (8 fps faster) with an ES of 10 over the string (12 previously).... The shot count, and the efficiency, increased 40%, to 1.49 FPE/CI (from 1.07).... I was absolutely SHOCKED and delighted by this result.... There is no question that the SSG can make a huge difference, particularly in a gun where you are pushing the power....
Bob
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A 1% es I do believe that helps those wanting tight 100 yard groups.. ;)
Was tight to begin with but every little bit matters I think...
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With unsorted pellets, 1% is about as good as it gets over large numbers of shots.... Pellets typically vary in weight plus or minus 1% or even more, so that can account for the 1% ES right there, if the FPE is held constant.... No way I'm going to start weighing pellets, because if there is really a difference in velocity and trajectory, then you would have to resight the gun for each weighed batch.... unless you just throw out anything more than 0.1 gr from the average, or use them for testing.... I'm just not a good enough shot to notice a 1% ES, even off the bench at 100 yards....
Bob
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Bob,
being your rifles are OPEN un-muffled barreled .... what sound signature differences are you hearing ?
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There was a small difference on the QB.... a much larger one on the first test gun and this 2260.... There is absolutely NO BUURRRPPPP that I can hear with the SSG installed wth a gap.... However, if you screw in the adjuster until you have any preload, instead of a gap, there is an instant doubling of the report.... I mean like LOUD !! ....
One thing I find extremely interesting.... Compared to the standard spring setup, when you are on the knee of the curve, approaching the plateau, the efficiency drops rather quickly, to the point going from, say, 950 fps to 980 fps might cost you double the air.... With the SSG, as long as you can maintain a gap, the efficiency doesn't drop as quickly.... It drops, yes, but not as fast as before.... Once you have preload on the SSG, however, the efficiency drops like a stone.... You can't mistake it when that happens, the report gets SO much louder.... It's almost like a switch, one more flat (1/6th turn) on the adjuster screw, you get another 20 fps but double the air used.... When there is a gap, it seems the velocity change is about 10 fps per flat (less with a fine thread)....
Bob
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I had unscrewed the shroud listening and noted the SNAP indeed seems a tad crisper ... also making note when stop rod adjusted too close ( yet hammer wiggled ) when fired report was louder !
Came to conclusion the o-ring on end of stop rod was COMPRESSING equal to / greater than the gap setting. so for that millisecond valve is open & shut the stop rod appeared to NOT MOVE out of the way fast enough and poppet sent hammer into stop rod screwing with the dwell timing.
Tad more gap being greater than compression yield of o-ring and all seemed well enough.
*On a side note, the most recent spring hat with the o-ring on the end to act as a rebound buffer between hammer and stop rod was installed this afternoon. Appears to work no different, tho it may be ??? Got no sound or optics equipment to validate.
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You can definitely tell when you have a gap.... no question about that.... It doesn't seem critical how big the gap is, from what I can tell as long as it's there.... The amount of gap certainly affects the velocity, however, with the speed dropping in a fairly linear fashion as you increase the gap.... As you drop the velocity, you use progressively less air, and the efficiency increases as well.... so you can trade off power for shot count by changing the gap....
Bob
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It would be easier if we could make a folding rod that holds the spring in compression, like the shell in shock absorbers. No need to drill the back plug or anything, just slip a compressed spring package in place of the original spring. Alternatively it could be a two piece shell around the spring where one half goes inside the other. Just add some sort of length adjustment to the package. Original power adjusters could be employed as well.
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Bob, Yes I find the exact same thing, as soon as you have a gap the efficiency is stellar, and as you increase the gap the velocity goes down in a fairly predictable and linear fashion. Which is good as you can use this to fine tune your fps as long as the overall setup is within range of the goal.
RKR: You could use a telescoping center rod with a retaining hat in both ends. However you lose one primary function of the SSG, and that is that the spring system is held firmly in place at the rear, so that the hammer can fly freely to the valve the same way, every time. Retaining the set gap at all times.
I am going to try to make the rear plug in two pieces, an outer shell (metal for the bolts and such) then an inner thinner shell with the rear rod hole in delrin, working as bearing surface for both the spring and the rod going through the rear.
Here is a simple diagram. The (pink) adjuster is a threaded piece and would push on the inner delrin "cup" In the diagram I drew it wrong, i.e. touching the delrin as it's turned all the way in, it would obviously not be that way in the final version.
(http://i54.photobucket.com/albums/g97/renderbrandt/SSG%20Diagram_2.png)
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If the pink aduster is a larger OD, you can remove the SSG "cartridge" through the hole in the rear cap to work on it, change springs, preload, whatever.... No need for a separate Delrin cup (sleeve).... the spring sits against the end of the adjuster.... a 3/8"-24NF bolt works great for Disco/QB sized springs....
rkr, I see what you are saying, a drop-in package that is a preloaded spring.... That could work, if you can find room for it, but it might preclude going to a longer, lighter spring to ease the cocking force, which is a major advantage.... If you didn't need that, or if you were trying to detune the gun, a drop-in setup that was adjustable for preload should work....
Bob
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If the pink aduster is a larger OD, you can remove the SSG "cartridge through the hole in the rear cap to work on it, change springs, preload, whatever.... No need for a separate Delrin cup (sleeve).... the spring sits against the end of the adjuster.... a 3/8"-24NF bolt works great for Disco/QB sized springs....
Bob
That's a good idea Bob.
(http://i54.photobucket.com/albums/g97/renderbrandt/SSG%20Diagram2.png)
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I do all mine that way, if possible.... even my Hayabusa with 1/2" OD springs, I use a 5/8" - 18 NF bolt to make the adjuster.... If the bolt is large enough, you can even drill it out to allow the (longer) spring to fit up inside the adjusting bolt.... Let's say a 1" long 7/16" bolt with a 5/16" (11/32") hole that is 7/8" deep for the spring to fit inside for Disco (or QB) springs....
Bob
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Here is a general arrangement for the Stopped Spring Guide, for those who may be having trouble seeing how it is built....
(http://i378.photobucket.com/albums/oo221/rsterne/Parts%20for%20Sale/SSG%20Cartridge_zpsz7nldexu.jpg) (http://s378.photobucket.com/user/rsterne/media/Parts%20for%20Sale/SSG%20Cartridge_zpsz7nldexu.jpg.html)
The black rod is the spring guide, I make it from the appropriate size drill rod, and the spring seat on the right from a nut, threaded on, peened in place with green Loctite and then machined to shape and the same OD as the spring.... It sits in the end of the hammer, with a small gap.... The green part is the adjusting nut to set the gap between the end of the guide and the inside of the hammer, and acts as a velocity adjuster.... I make it from a fine thread bolt, and you will need to prevent it from self-adjusting, either with a locknut, or a plastic plug pushed against the side with a setscrew, as a brake.... It is threaded into the purple part, which is the rear end cap for the tube, tapped to accept the bolt.... The blue is a 90D O-ring that fits the guide.... The red is a nut, threaded onto the end of the spring guide, and can either be a NyLoc, two nuts locked together, or tightened against a shoulder on the guide (if you don't need it adjustable).... It sets the preload on the spring....
You use a longer, lighter spring than normal, with significant preload, perhaps 1/3 of the cocking force.... You want enough preload that with the guide just touching the hammer the gun will shoot the highest velocity you want (or is capable of with the porting and pressure you are using).... It is therefore a good idea to know what the gun can do before you start playing with springs.... When properly set up, with the correct spring and preload, you will be able to adjust the gun over a wide range of velocity by adjusting the gap, up to the point where the end of the guide hits the hammer.... If you reduce the gap to zero or tighter (actual preload on the hammer), the gun will waste a LOT of air for very little increase in velocity, because the preload will prevent the valve from closing quickly, blowing air out the barrel after the pellet has left.... The muzzle report will be a dead giveaway if you do that, it gets MUCH louder if there is no gap....
Bob
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Today I revisited my .30 cal Grizzly, which is the first gun I installed an SSG into, last summer.... The gun has a 22 CI 3000 psi tank and is regulated at 2200 psi.... I went over my records and found that I had tried five different hammer spring setups in the gun.... The first setup was a 3" long x 0.051" wire spring (15 lb/in), and by the time I had it tuned for the power I wanted the preload was about 0.3", and the cocking effort was about 18 lbs..... I was getting about 16 shots per fil, with the efficiency teasingly close to 1.0 FPE/CI, which wasn't bad, but I wanted better.... I changed to a 2.5" long x 0.055" wire spring (24 lb/in) with 0.18" of negative preload (gap), and the gun was very hard to cock, especially right at the end of the stroke where it peaked at over 20 lbs.... The gun still had some obvious hammer bounce, even with the short stiff spring rattling around loose when uncocked, and it was so easy to NOT pull the bolt handle back all the way, I was getting many double feeds from the MRod magazine because I didn't quite get it cocked.... I got a maximum of 18 shots per fill.... I then tried a 3" long x 0.047" wire spring (11 lb/in) with lots of preload, and while the gun was much nicer to cock, with less than 14 lbs. of force required, and still gave me the performance I was after, the hammer bounce was horrific, and the efficiency was terrible to match.... It was down to about 12 shots (less than 2 magazines)....
I then made the first SSG, using that same spring, and I couldn't get enough power, so I increased it to a 3" long spring with 0.049" wire (13 lb/in) with 0.55" of preload (7 lbs.) and a gap of 0.12" between the guide and hammer.... That resulted in a maximum cocking force of less than 18 lbs. (the way I started), but it felt MUCH lighter and smoother because it started at 7 lbs.... I never again had a problem with incomplete cocking or the MRod magazine feeding two pellets as a result.... If I reduce the gap to minimum, the gun will reach 1000 fps with the 44.8 gr. JSB pellets, and I am running it 2 turns out from there, where it shoots 967 fps average (93 FPE).... I get 16 shots down to 2200 psi (50 psi per shot) within a 1% ES, and I can shoot a total of 3 mags (21 shots) before the velocity falls to 952 fps (2%ES), at which point the pressure is down to 1920 psi.... That works out to an efficiency of 1.19 FPE/CI, which I think is pretty good at that power level.... My original goal was 2 magazines on a fill.... I got 3.... Here is how the SSG all started....
(http://i378.photobucket.com/albums/oo221/rsterne/Flying%20Dragon%20PCP/Limited%20Stroke_zpskvdgiaqn.jpg) (http://s378.photobucket.com/user/rsterne/media/Flying%20Dragon%20PCP/Limited%20Stroke_zpskvdgiaqn.jpg.html)
Bob
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Lol Bob .... as did I work with my .177 Field target prepped M-rod.
Rifle prior to todays fiddling was working just great delivering @ 82 shots under regulation with 10.3 JSB's at 910 fps.
Hammer weight was a mere 14 grams utilizing the OEM 6# spring with @ 2 1/4 turns preload .... Past shot stings showed efficiency in the 1.40 range.
But hey, ya never know if more there unless you go for it .... right 8)
So right away found out like I had with the .22 M-rod that these SUPER LIGHT hammers don't make the power with the SSG system using the same 6# spring preloaded to the max. Add some hammer weight and they do !! ( The .22 had a 20 gram and require 28 grams. The .177 shared here today had 14 gram and needed 24 grams ) while these hammers weight are ridiculously light by common practice standards, they work so they stay ;)
Ok TODAYS parts built similar to other rifle using a SS 8-32 screw, tho this time screw head is a lot smaller and has a low friction nylon sleeve down shank. ( Was there so left it on ) Hat made like the last one done for the .22 using the same wedge undercut to hang onto an o-ring with @.020" compression to bottom out yield. Length for preload and a barrel shape also done for minimal drag. Head of screw & o-ring pocket into a counterbore to clean up the look.
Parts used like this ...
(http://i1320.photobucket.com/albums/u532/scott_schneider1/DSCF9927_zpstr54l1s2.jpg)
Assembled like this ...
(http://i1320.photobucket.com/albums/u532/scott_schneider1/DSCF9928_zpsdwlpxaou.jpg)
(http://i1320.photobucket.com/albums/u532/scott_schneider1/DSCF9925_zps49iwpz28.jpg)
(http://i1320.photobucket.com/albums/u532/scott_schneider1/DSCF9926_zpsgqcqvwjp.jpg)
(http://i1320.photobucket.com/albums/u532/scott_schneider1/DSCF9929_zps7ivtkcaz.jpg)
So with some preload fiddling was able to get the 10.3's back at 910 fps using the OEM 6# spring, tho more hammer weight.
QUIET !!! is an understatement ... think a mouse fart makes more racket !! JUST WOW
Loaded up my 8 magazines and went outside blasting away till empty ... HUH, still got air left with gauge still setting at set point pressure, so load up 2 more mags shooting 1 making 90 shots and gauge still not moved, start shooting the 10th mag while watching gauge for movement ... 97th shot detect maybe a drop & take the last 3 over the chrony ... yes it was off regulation yet velocity was still 905 to 895 on the last 3 shots.
Into Lloyds efficiency calculator to crunch the numbers .... :o avg FPE/cuin per shot 1.73
( 3k fill, 1.7 set point, 190cc tank, 10.3 g, 95 shots, 910 fps )
Bob ... we have a winner design going on here ... Wow hardly seems sufficient.
Scott
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Hey, Scott, that's pretty KEWL !!!.... Congratulations.... I'm glad to help, and delighted that you have confirmed my findings.... I'm sure you will turn this idea into a bunch of happy customers with a drop-in (or at least tuner installed) setup.... and good on ya! for that !!!.... Advancing the sport is what it's all about for me.... and it's not often you can lay claim to (dare I say it?) a breakthrough.... I'm just having a blast retrofitting my PCPs to see what gains I can make.... 8)
Bob
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I'm just having a blast retrofitting my PCPs to see what gains I can make.... 8)
Bob
Indeed ... sadly for some of my personal guns having vertical thumb rests right behind main tube this mod is not going to make sense.
I am however excited to see what can be done with the BAM 50 .25 cal conversion however.
Scott
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Bob,
When you get around to retrofitting your AT-44, please do post! I have ideas, but I don't have the spare parts and machining equipment around, so I don't want to start "chopping up" the only working parts I have just yet. I've now managed to get my .22 AT-44 touching the 55fpe mark, but it is an air hog doing it. Needless to say, if I could figure out a solution like the SSG that will work with the hammer and spring set up on it, that would be awesome. Given that the spring is basically hanging out in the hammer in there, I'm not sure on the best way to make that happen. You guys are way more likely to succeed than I :D
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I didn't say I was going to convert EVERY PCP I have.... *LOL*.... Yes, the AT-44 could be quite a challenge, and since it already has an anti-bounce device, may not be worth it....
Bob
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I didn't say I was going to convert EVERY PCP I have.... *LOL*.... Yes, the AT-44 could be quite a challenge, and since it already has an anti-bounce device, may not be worth it....
Bob
Along with the fact diameter of hammer spring is so small .... getting the energy to valve could be troublesome ???
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Is the At-44 worse than the disco?
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One of the upsides with the SSG is you can "buy" length in the rear cap for the mechanics of it.
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To tell you the truth, it's been so long since I had mine apart I can't remember the details.... It does use a fairly small OD spring, but that makes it stiff (high rate).... Lots of room for a long spring if you take out the spacer and shorten the front spring adjusting screw inside the hammer.... I don't know what would be involved in attaching it inside the tube and moving the adjustments to the back, assuming there is room in there.... At some point I may find out, if I run out of other projects.... *LOL*....
Bob
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You guys are all a bad influence! Instead of doing what I was supposed to be doing today I was fiddling with Bob's new SSG device.
First, gotta say, Bob and Scott, you are both very sick and apparently cannot be stopped. Lucky for the GTA, ha, ha. It is amazing how quickly great work can get done when the OCD kicks in.
So I had to fiddle with the cocking rod version of the SSG to fit in a Disco tube. Darn if it didn't work! It needs some refinement, but it isn't too far off.
Here are the parts and pieces. The spring guide is a piece of 1/4 O.D. x .029 wall SS tubing, threaded 1/4-28 at each end. The makeshift cocking rod is a piece of 3/16, stiff 17-4Ph SS rod that threads down inside the hammer. I had to heat it to bend it. The adjuster with the 1/2-20 male thread has a stepped hole thru it for the spring guide and the cocking rod. There is a partition inside of it that retains the spring. The partition is closer to one end than the other so that it can reversed if you need to get within a different adjustment range for heavier or lighter springs. The jam nuts for the spring guide are actually 8-32 nuts that I tapped out to 1/4-28 so that they would fit down inside the 1/2-20 adjuster.
(http://i226.photobucket.com/albums/dd79/loyd500/Miscellaneous%20pics/20160104_224925_zpsub0tj1de.jpg) (http://s226.photobucket.com/user/loyd500/media/Miscellaneous%20pics/20160104_224925_zpsub0tj1de.jpg.html)
This picture shows how the spring guide and its damper and jam nuts get swallowed up inside the 1/2-20 adjuster.
(http://i226.photobucket.com/albums/dd79/loyd500/Miscellaneous%20pics/20160104_225106_zpsrysiemwx.jpg) (http://s226.photobucket.com/user/loyd500/media/Miscellaneous%20pics/20160104_225106_zpsrysiemwx.jpg.html)
Here is the total assembly ready to be fitted into the gun. The cocking rod is bent like that to give plenty of clearance for the particular thumb hole stock this is going into. At this time, the spring preload is already set, and can't really be changed once installed in the gun. However, the hammer rebound clearance does get adjusted after the installation is made.
(http://i226.photobucket.com/albums/dd79/loyd500/Miscellaneous%20pics/20160105_004443_zpsuxlhsdfi.jpg) (http://s226.photobucket.com/user/loyd500/media/Miscellaneous%20pics/20160105_004443_zpsuxlhsdfi.jpg.html)
This cocking rod version is only needed if you want to use a heavy spring to get power. I think this is the same spring Bob mentioned earlier: .051 wire x 3" long x .360 dia x 25 coils.
Progress usually takes time!
Lloyd
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Lloyd, could you explain the function of that rod? I am getting lost in so many info lol ;D good work guys!
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Lloy, could you explain the function of that rod? I am getting lost in so many info lol ;D good work guys!
Sure thing. The Disco has that cheesy little bolt handle that locks the bolt into the breech but also pulls the hammer back via an offset little pin, and also compresses and cocks the spring. In a stock Disco with a light weight hammer spring, that arrangement works just fine. But if you want more power, that usually means (among other things), a stiffer spring. Sometimes the little bolt handle is not up to the task and breaks, or the hammer tends to bind from being pushed cockeyed against the spring. The new cocking rod is threaded straight into the hammer, thru the middle of the spring, so that you can pull the spring straight back, without any side loading, and without putting undue stress and wear and tear on other parts of the system. The cocking rod idea has been around for a long time and helps a lot for higher power versions of the Disco, and similar design guns.
Lloyd
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Im starting to hate all you guys especially Bob for starting this and Lloyd for feeding the fire and Scott for doing it, That's it I do hate all you uns. David
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Lol Bob .... as did I work with my .177 Field target prepped M-rod.
Rifle prior to todays fiddling was working just great delivering @ 82 shots under regulation with 10.3 JSB's at 910 fps.
Hammer weight was a mere 14 grams utilizing the OEM 6# spring with @ 2 1/4 turns preload .... Past shot stings showed efficiency in the 1.40 range.
But hey, ya never know if more there unless you go for it .... right 8)
So right away found out like I had with the .22 M-rod that these SUPER LIGHT hammers don't make the power with the SSG system using the same 6# spring preloaded to the max. Add some hammer weight and they do !! ( The .22 had a 20 gram and require 28 grams. The .177 shared here today had 14 gram and needed 24 grams ) while these hammers weight are ridiculously light by common practice standards, they work so they stay ;)
Ok TODAYS parts built similar to other rifle using a SS 8-32 screw, tho this time screw head is a lot smaller and has a low friction nylon sleeve down shank. ( Was there so left it on ) Hat made like the last one done for the .22 using the same wedge undercut to hang onto an o-ring with @.020" compression to bottom out yield. Length for preload and a barrel shape also done for minimal drag. Head of screw & o-ring pocket into a counterbore to clean up the look.
So with some preload fiddling was able to get the 10.3's back at 910 fps using the OEM 6# spring, tho more hammer weight.
QUIET !!! is an understatement ... think a mouse fart makes more racket !! JUST WOW
Loaded up my 8 magazines and went outside blasting away till empty ... HUH, still got air left with gauge still setting at set point pressure, so load up 2 more mags shooting 1 making 90 shots and gauge still not moved, start shooting the 10th mag while watching gauge for movement ... 97th shot detect maybe a drop & take the last 3 over the chrony ... yes it was off regulation yet velocity was still 905 to 895 on the last 3 shots.
Into Lloyds efficiency calculator to crunch the numbers .... :o avg FPE/cuin per shot 1.73
( 3k fill, 1.7 set point, 190cc tank, 10.3 g, 95 shots, 910 fps )
Bob ... we have a winner design going on here ... Wow hardly seems sufficient.
Scott
NICE work Scott. I really like the craftsmanship and obviously the results.
I am working on building one of these and wondered if you guys had some advice on a couple things.
This is going into a Disco using a Prod hammer which is already relieved and working in the gun.
Parts thus far:
- 3/8-24 Banjo bolt drilled out to 11/64 (.203 )
- 5mm machined steel rod ( taken from a piece of imported office equipment = .196)
- 10-24 stainless nuts ( have to source yet )
- Prod rear cap ( already 3/8-24 threaded internally )
Plan is to fully thread the Prod cap from the inside out using a tap. Conveniently the spring guide that comes with the cap is already this thread so I just need to finish it right out the back end. I've already drilled and tapped holes for the cap for use in the disco tube BTW.
Question:
I see Bob used a 2200 spring for Disco application. What gauge wire and length is that spring? How strong is it?
I have 1322 springs. Would the 1322 work or do you suggest getting a 2200 spring from Crosman or something else?
The 5mm rod in the 13/64 hole seems like a nice, tight, arrangement but I'm debating getting piece of 7075 aluminum rod 5mm instead to reduce mass.
The 5mm is only slightly thicker than the 3/16 and it's only a 3" section so maybe no worries.
Any thoughts on that idea? I'm thinking a lighter spring might be possible with the lighter rod.
I suspect all this is a matter of try it and see but wanted some feedback from yous guys.
Thanks!
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The 13XX spring is the same length as a Disco spring, but smaller wire.... The 2200 spring is the same wire as the early Disco spring, but longer.... I have no idea what the new Disco spring is.... I think the ideal spring for a stockish Disco might be one like a longer 13XX spring, but don't know of, or have one, currently.... I would look for something about 0.032-0.033" wire and 2.5" long.... Since the springs are riding on a close fitting rod (in my SSGs), you can also use two springs (with closed ends) butted together.... You should be able to use two 13XX spring, with a total length (after being set, so they don't get any shorter) of about 2.5" uncompressed, preloaded about 3/4"-1" (roughly).... Another alternative might be two of the original Disco springs, with a total length of about 2.3-2.5" (after being set), with 1/2-3/4" preload (roughly).... If you use longer springs, of course, you will need a custom end cap / adjuster bolt further back.... Sorry this is still in it's infancy and no set answers are available....
Bob
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The 13XX spring is the same length as a Disco spring, but smaller wire.... The 2200 spring is the same wire as the early Disco spring, but longer.... I have no idea what the new Disco spring is.... I think the ideal spring for a stockish Disco might be one like a longer 13XX spring, but don't know of, or have one, currently.... I would look for something about 0.032-0.033" wire and 2.5" long.... Since the springs are riding on a close fitting rod (in my SSGs), you can also use two springs (with closed ends) butted together.... You should be able to use two 13XX spring, with a total length (after being set, so they don't get any shorter) of about 2.5" uncompressed, preloaded about 3/4"-1" (roughly).... Another alternative might be two of the original Disco springs, with a total length of about 2.3-2.5" (after being set), with 1/2-3/4" preload (roughly).... If you use longer springs, of course, you will need a custom end cap / adjuster bolt further back.... Sorry this is still in it's infancy and no set answers are available....
Bob
Great info - thanks Bob!
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Lloyd, great to see your rear cocking SSG is taking shape.... and I look forward to your tests.... I have one piece of info you (and others) will find helpful.... The hammer needs AT LEAST the same energy it had originally to do its job.... but now the spring is accelerating extra weight.... so the hammer is going slower (if you don't increase the spring energy), plus it has to coast while in contact with the valve.... You need to get that hammer velocity back with more spring energy.... In Lloyd's case, not very much extra (a thin tube, he already had the cocking rod).... in the case of my 37 FPE 2260 HPA a bit more, because although it had a spring guide (that helped the hammer strike), now that guide is no longer part of the hammer energy (it stops before the hammer hits).... If your original hammer used a short, stiff spring, the hammer was already coasting the last bit, but now you have added all the mass of the guide to the system.... and in the worst case (the normal one for most PCPs), where you had a preloaded spring pushing the hammer the entire cycle, now you added the weight of the guide, PLUS the hammer is coasting all the time it touches the valve.... I haven't put any numbers on it yet, but I'm thinking you need to increase the total spring energy stored by 20-50%.... most of which is the preload in the spring....
Bob
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Lloy, could you explain the function of that rod? I am getting lost in so many info lol ;D good work guys!
Sure thing. The Disco has that cheesy little bolt handle that locks the bolt into the breech but also pulls the hammer back via an offset little pin, and also compresses and cocks the spring. In a stock Disco with a light weight hammer spring, that arrangement works just fine. But if you want more power, that usually means (among other things), a stiffer spring. Sometimes the little bolt handle is not up to the task and breaks, or the hammer tends to bind from being pushed cockeyed against the spring. The new cocking rod is threaded straight into the hammer, thru the middle of the spring, so that you can pull the spring straight back, without any side loading, and without putting undue stress and wear and tear on other parts of the system. The cocking rod idea has been around for a long time and helps a lot for higher power versions of the Disco, and similar design guns.
Lloyd
Now I get it, thanks!
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Im starting to hate all you guys especially Bob for starting this and Lloyd for feeding the fire and Scott for doing it, That's it I do hate all you uns. David
David,
Come on in, waters warm and beers cold.
Sittin on side line "Haten" is non productive .... Get out in the shop and Make sum thing !!!
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just like to thank you Bob for sharing this innovative concept and all you other chaps for sharing your work and variations of it
once I get a bit of time I'm going to knock one up in the man cave and see how it works with sub 12fpe(sadly our limit)and co2
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Found a great setting on the .22
Knew I had a 10# spring someplace, just needed to find it !
Took hammer spring preload to full soft, cut down the Hats spring shoulder some as well to take hammer spring to less preload.
Over onto the chrony ... 920 fps with 18.1's WOWZER we have some power now !
Dismantled and took some more off the hats spring shoulder further reducing preload by @ .080"
Back together testing again ... 895fps & PERFECT !
Cocking effort just a tad stiffer with the 10# spring with @ 3/8" preload than the 6# at near coil bind. In terms of cocking effort really no big deal.
So what this does ADD to Bobs original thoughts about softer springs with a LOT of preload, is that a stiffer spring with less works too ;)
Side benefit tho not proven as of yet ... with the heavier spring fitted the speed of hammer strike actually gets valve open quicker, tho because hammers coasting poppet closes just as quickly. DWELL does seem to have decreased listening to muzzle report becoming crispier/snappier sounding ???
Scott
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Ok I'll play lol http://i.imgur.com/8N4xqpzh.jpg (http://i.imgur.com/8N4xqpzh.jpg) http://i.imgur.com/mrYhQfEh.jpg (http://i.imgur.com/mrYhQfEh.jpg) http://i.imgur.com/zZjxC0lh.jpg (http://i.imgur.com/zZjxC0lh.jpg) http://i.imgur.com/G9PyCWRh.jpg (http://i.imgur.com/G9PyCWRh.jpg) Good start I think. I can preset hammer spring tension and then set how much float I want.
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I knew you would Travis! (I can't keep you two apart) That and the fact I talked with Jim yesterday about the SSG....lol
Let us know what you find on the Flex.
:P
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Ok I'll play lol http://i.imgur.com/8N4xqpzh.jpg (http://i.imgur.com/8N4xqpzh.jpg) http://i.imgur.com/mrYhQfEh.jpg (http://i.imgur.com/mrYhQfEh.jpg) http://i.imgur.com/zZjxC0lh.jpg (http://i.imgur.com/zZjxC0lh.jpg) http://i.imgur.com/G9PyCWRh.jpg (http://i.imgur.com/G9PyCWRh.jpg) Good start I think. I can preset hammer spring tension and then set how much float I want.
Travis ... welcome
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The FLEX already has a similar system in place. This does however look to be a great upgrade for many air rifles.
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I got the gauge for my .25 pumper, Bob. I have not had time to install it. I will be doing the SSG to my gun also.
Will I need a heavier hammer spring or a lighter but longer spring? Thanks Bob!!!
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On another note & question for Bob ???
In terms of strike energy stored in springs AND THE LONG TERM CONSISTENCY ....
would not a spring spending most of it's life with a LOT of preload, then stressed to near coil bind when cycled have a SHORTER LIFE and suffer from SACKING OUT much faster than a slightly stiffer spring with far less preload while being nowhere close to coil bind when cycled ?
Where as shown in a earlier chart, BOTH exhibit close to the same energy as differing preloads.
Thinking too much .... my bad .
Only asking this for terms of LONG TERM CONSISTENT setting having fitted AG be less finicky over time.
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I am working the bits similar to Travis, only with a 3"an push the preload up, leave minimum amount of spring/guide adjustment. Going to turn a bit for the OE Marauder endcap in 9/16-20 for the float, and a guide of Aluminum turned to .25"( for 1/4-28 nuts ). Will try a .062" wire spring first; around 17 lb/in or so. I hope to get the .224's valve well open at 3k psi...as I have never gotten the highest power out above 2k7 psi.
cheers,
Douglas
--this will run the A7 sear...:)
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Motorhead; as I understand from some of the more experienced, engineer-type contributors on various firearms-related forums, fear of magazine springs getting weaker is primarily a worry of those less experienced. Many have said that it's not static compression which bags out springs, it's cycling. So those who obsessively empty and fill their magazines are the ones most likely to see springs getting weaker. Leaving mags loaded for years is like loading them once, no matter how long they're stored, provided there's a bit of oil and the springs don't rust... but that degrades the springs in either compressed or uncompressed state so not really relevant.
That said, I've seen the odd airgunner saying that leaving a break-barrel or other spring-piston air rifle cocked for long periods weakens the mainspring. So I'm not completely certain who to believe... though the expertise among the firearms guys has generally seemed deeper where the anecdotal stuff about springers has been a bit less informed-sounding.
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Scott, I have no doubt that the SSG will work with (relatively) shorter stiffer springs, providing you can get the travel you need without hitting coil bind.... I'm not so sure why it would give increased hammer velocity, though, because if it did, your power would go up, assuming you weren't on the velocity plateau.... In theory, at least, all setups that produce the same hammer velocity at the valve (when the guide stops), and have the same hammer stroke, would require the same average spring force.... It shouldn't matter if you start with 0 lbs. force uncocked and go to 20 when cocked.... start at 5 lbs. and go to 15.... or start at 9 lbs and go to 11.... the average force is 10 lbs, and if the guide moves 1.2" that is 1 FPE (10 x 1.2 = 12 in.lb) of energy.... What is likely happening is that when you use a stiffer spring, you are using a larger gap, and as you lengthen the gap, you shorten the compression, to make up for that higher average force.... ie you are flinging the hammer at the valve from further away.... The thing that will happen, if, for instance you use the stock spring and preload it, is that you will increase the cocking force by the amount of preload.... Some guns, that won't matter, on my Grizzly, for example it wasn't acceptable to increase the cocking force even further....
My experience with springs is that once they are "set".... ie fully compressed to coil bind.... they don't change, at least I have never seen it.... I always set my hammer springs before installing them the first time.... ALWAYS.... The first time I increased the preload on a Disco hammer spring until I hit coil bind, as soon as I backed it off I got lower velocity readings than before.... I took the spring out and measured it, and it was over 1/8" shorter than when new.... Recorded all the preload vs velocity data with the shorter "set" spring and never had it change again....
The data I have seen on leaving Springers cocked is that they lose about 1% a week for the first month, then 1% a month for a few months to about 10-15% loss, then stay that way.... and I'm betting they didn't bother to set the spring before they started their measurements.... Seriously, I really doubt the hammer spring getting weaker with time is an issue, PROVIDING you set the spring to coil bind (I do it maybe 10 times in quick succession) before installing it.... The preload on the SSG will be only about 1/3-1/2 of the force at coil bind anyway....
Travis, welcome aboard.... I look forward to hearing your results.... This, for me, is exciting....
Bob
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Scott, I have no doubt that the SSG will work with (relatively) shorter stiffer springs, providing you can get the travel you need without hitting coil bind.... I'm not so sure why it would give increased hammer velocity, though, because if it did, your power would go up, assuming you weren't on the velocity plateau.... This, for me, is exciting....
Bob
In this rifle with the 6# spring at coil bind when cocked maxed out at 835 fps with 18.1's
Going to the 10# spring ( Same OAL ) took preload down to 1/4 of what it was.
so we do have more spring energy at hammer obviously being velocity jumped up to +/- 900fps with same pellet.
also where the hammer speed came from no doubt. Odd part is & why noting it, even tho power jumped up the noise really did not, actually becoming sharper/crisper without really seeming louder.
Anywho ... Thanks
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Scott, how did you get a 6# spring to coil bind in a Marauder?
cheers,
Douglas
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I didn't say I was going to convert EVERY PCP I have.... *LOL*.... Yes, the AT-44 could be quite a challenge, and since it already has an anti-bounce device, may not be worth it....
Bob
Along with the fact diameter of hammer spring is so small .... getting the energy to valve could be troublesome ???
You guys are no fun, lol! I would like to come up with something, because that anti-bounce "device" is taking a beating at 55fpe I think... That is part of the reason I want to come up with a damper/hammer set up. I can adjust the bound \rebound independently, and I think it would work if I get it right. I suppose a damped hammer stop could be another way to approach it too. I just don't think that anti-bounce device is living up to the gun's potential. Its using a lot of air, and making some noise at that power level. I have a few different ideas, but I need to order some spare parts, before I go down that road :)
I also feel like I could do it with a factory spring without that hammer stop there. My internet is down, and I'm on 4G right now, so I can't do any show and tell, but I WILL come up with something. It will take me longer than you guys though. Just a little background on me, so you don't think I'm completely crazy, but I have done formula BMW race engineering, and SCCA stuff. I say that so you guys understand I have no shortage of ideas on how to do it. The damper \spring set up on those formula cars gets pretty crazy. No, I'm not going to put cantilever suspension on my gun, ha-ha!
I'm really learning and enjoying the heck out of this discussion either way though!
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Scott, how did you get a 6# spring to coil bind in a Marauder?
cheers,
Douglas
Preloading the rear cap to the max then spacing it further via the hat on stop rod down in hammer cavity.
Together coils get to coil bind when cocked ....
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Hey Guys,
It's good to see everyone on the GTA having such a good time with a new mod 8).
It reminds me of the first time I heard about making smoke bombs & gun powder!! I thought, Wow :D you can do that? ...... now those were the days ;D
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Second effort http://i.imgur.com/y6QrAMUh.jpg. (http://i.imgur.com/y6QrAMUh.jpg.) http://i.imgur.com/3mgBejKh.jpg (http://i.imgur.com/3mgBejKh.jpg) http://i.imgur.com/seeZLwYh.jpg (http://i.imgur.com/seeZLwYh.jpg) http://i.imgur.com/I5iPgydh.jpg (http://i.imgur.com/I5iPgydh.jpg) http://i.imgur.com/iayJKs4h.jpg (http://i.imgur.com/iayJKs4h.jpg) I have a MUCH better way but will have to wait till tomorrow.
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I'm seeing some very good results only problem is to get pellets to speed requires to much spring tension in a marauder due to short hammer throw but I think if I put in my valve this will only require a 6 lb spring other than that I'm seeing very very good numbers and being able to change springs and tune externally is the bees knees. I just had 5 shots in a row with 0 fps deviation!!! BOB this is really a good mod! More work tomorrow it's beer thirty here.
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I'm seeing some very good results only problem is to get pellets to speed requires to much spring tension in a marauder due to short hammer throw but I think if I put in my valve this will only require a 6 lb spring other than that I'm seeing very very good numbers and being able to change springs and tune externally is the bees knees. I just had 5 shots in a row with 0 fps deviation!!! BOB this is really a good mod! More work tomorrow it's beer thirty here.
Travis,
IMO your size & WEIGHT of stop rod is absorbing too much energy.
Also by having smaller diameter poppet valve installed, required energy to crack it open becomes less.
Just suggesting ....
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I used the same size rod that Bob used 3/16. Not convinced it's the issue. I'm using a bone stock .25 shooting around 800 FPS average with a 12lb spring at around 2600 psi. I had it at 840 before with stock spring. Still much improved over stock set up. Tomorrow I'll run a full string and post. I believe I need to polish the rod and adjuster to a very smooth finish. Or go Delren on insert like Scott suggested earlier.
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Have never been one to obsess about efficiency...tune to a happy point that suites the designated task and shoot the sh1t out of it. Shot count falls where ever it does.
That said...this IS interesting. 8)
I do have one issue with this though, and I admit it could be just me... I abhor things sticking out the back of the pressure tube into my hand...for this reason, my rva's are entirely in the tube. Had a thought while reading through the thread here and did up a quick sketch.
(http://i245.photobucket.com/albums/gg76/gippeto_album/ssg_zpsj7jafvqr.jpg) (http://s245.photobucket.com/user/gippeto_album/media/ssg_zpsj7jafvqr.jpg.html)
Al
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While a lighter guide can't hurt, I don't think it's critical, either.... The 2260 HPA where I got a 40% increase in shot count used a 7/32" guide about 3" long.... That would weigh 15 grams, plus the nuts, and the hammer is a stock Disco at 60 grams, so the guide assembly will be almost a quarter of the total mass the spring has to accelerate.... Since Scott is working with extremely light hammers, I can see why he wants to cut the "stop rod" (as it isn't really a guide, it's much smaller) down in weight.... Since hammer energy (lift) is a function of spring force and travel, while the hammer weight only affects the momentum (dwell), we are back to the situation of having many solutions that all work.... The cool thing is that they ALL seem to be saving air....
Al, is the grey part the hammer?.... and the guide slides down inside it?.... no reason that shouldn't work.... BTW, did you notice my QB with the cover over the back?.... nothing sticking out there....
Bob
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Im starting to hate all you guys especially Bob for starting this and Lloyd for feeding the fire and Scott for doing it, That's it I do hate all you uns. David
David,
Come on in, waters warm and beers cold.
Sittin on side line "Haten" is non productive .... Get out in the shop and Make sum thing !!!
You can bet I want in but I have a shop full of barrels and bb guns that if I don't get done I could get hanged, I just hate I cant play right now. David
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Im starting to hate all you guys especially Bob for starting this and Lloyd for feeding the fire and Scott for doing it, That's it I do hate all you uns. David
David,
Come on in, waters warm and beers cold.
Sittin on side line "Haten" is non productive .... Get out in the shop and Make sum thing !!!
You can bet I want in but I have a shop full of barrels and bb guns that if I don't get done I could get hanged, I just hate I cant play right now. David
Darn, David, sounds like you got yourself in a real pickle, ha, ha. Just how did you manage to do that??? Don't you wish you could have your clone doing all the "obligation" work for you while you got to play with the fun development stuff? Or maybe you could even work on your OWN guns? ;) Now that is a very novel idea!
Now you gotta stop haten us >:( cause we be lubbin yew! :-*
Lloyd
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Bob....the cover sticks out more than I would like for my own use.
Rva on my qb...adjusts via hex wrench.
(http://i245.photobucket.com/albums/gg76/gippeto_album/IMG_3842_zps89b9d3f2.jpg) (http://s245.photobucket.com/user/gippeto_album/media/IMG_3842_zps89b9d3f2.jpg.html)
Al
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Al,
That is definitely a nice clean look on your QB. I have to admit that I don't care for the stuff moving in and out of the back end and have always just considered it a necessary evil. Guess it should be looked at as "an opportunity for improvement. "
Lloyd
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I'm seeing some very good results only problem is to get pellets to speed requires to much spring tension in a marauder due to short hammer throw but I think if I put in my valve this will only require a 6 lb spring other than that I'm seeing very very good numbers and being able to change springs and tune externally is the bees knees. I just had 5 shots in a row with 0 fps deviation!!! BOB this is really a good mod! More work tomorrow it's beer thirty here.
This got me thinking, it's soon beer o'clock here as well. The zero fps deviation, could it be caused by zero preload on the hammer and reduced hammer mass? Think about it, when hammer normally hits the valve it is under tension by the spring and moving fast forward. When it suddenly meets the valve stem it slows down pretty fast while still being pushed by the spring. This then should cause the hammer to rock sideways a bit causing extra friction and what not. In case of this SSG there's no spring pushing the hammer and even the mass of the hammer has been reduced. Thus the hammer should rock sideways less on impact causing less friction and perhaps more even energy transfer on the valve?
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Would it be possible to make a 2 or 3 piece, telescopic spring guide? The intention here would be to eliminate or minimize the amount of spring guide protrusion when cocked.
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I'm seeing some very good results only problem is to get pellets to speed requires to much spring tension in a marauder due to short hammer throw but I think if I put in my valve this will only require a 6 lb spring other than that I'm seeing very very good numbers and being able to change springs and tune externally is the bees knees. I just had 5 shots in a row with 0 fps deviation!!! BOB this is really a good mod! More work tomorrow it's beer thirty here.
Travis,
IMO your size & WEIGHT of stop rod is absorbing too much energy.
Also by having smaller diameter poppet valve installed, required energy to crack it open becomes less.
Just suggesting ....
I'm going to try 7075 aluminum for the stop rod for this reason. Hopefully no galling will occur but I'm going to polish the bore of the rear bolt and use graphite + moly lube and see how it goes. I have to build it first!
I don't have a heated shop. Michigan had a nice December but January looks like it's going to be less comfortable in that regard.
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Would it be possible to make a 2 or 3 piece, telescopic spring guide? The intention here would be to eliminate or minimize the amount of spring guide protrusion when cocked.
1 piece guide would probably be enough as those rear plugs are rather thick and having it go inside the plug increases travel. A telescopic rod attached to the rear plug would eliminate the need to have the rod protrude outside the gun. I have a design that would work in my BSA, unfortunately I don't have a lathe so implementation is still question mark.
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I've been trying to keep up with this thread to the best my primitive, non-physics-inclined mind will let me.
For those getting good results on the Mrod platform, what are you setting your hammer stroke to? Long or short?
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I've been trying to keep up with this thread to the best my primitive, non-physics-inclined mind will let me.
For those getting good results on the Mrod platform, what are you setting your hammer stroke to? Long or short?
FULL stroke +
Taking the strike screw in the last .090" to flush adds even more.
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Very nice RVA on the QB, Al.... it is somewhat unique in that it has extra room between the back of the hammer and the rear of the tube to allow the RVA to be inside.... That is why I could easily fabricate a cover for the SSG on mine.... One thing I can see with your design, is that the entire length of the preloaded spring must be behind the hammer, none of that length can be contained inside it.... The hole in the hammer has to be the depth of the hammer stroke, plus the valve lift, plus the short stub of guide sitting in it when uncocked (as drawn)....IMO, the guide should protrude into the hammer by the amount of valve lift (when uncocked), to make sure it can't hop out of the hole and jam the hammer open.... At the back of the guide, you still have to have some way to locate it in the end cap, and adjust the spring preload and the gap between the red collar and the back of the hammer (governed by the guide length).... If you look at my drawing in Reply #105, much of the length of the spring is contained inside the hammer and the green gap adjusting nut, in fact the hammer can nearly touch the adjusting nut when cocked.... The front of your spring must start behind the back of the hammer, so the back of the spring must be further back.... I don't think you will save anything on overall length, but I do like the idea of the fixed guide, because the spring won't have to expend any energy in accelerating it....
rkr, I think that having the hammer flying free while it is opening the valve may be what is helping the ES.... In most conventional PCPs, there is enough preload on the spring that it is still in contact with the hammer throughout the valve cycle.... For instance, in a Disco, you have about 1/4" of preload, and the valve only opens 1/16-1/8".... The hammer spring is, in effect, helping to open the valve, and retarding it's closing, through the whole cycle.... I realized this when I saw what happens as soon as you eliminate the gap on a SSG and have any preload.... Since the preload is several lbs., it really slows the closing of the valve, greatly increasing the report and air use.... I would postulate, therefore, that any "normal" preload on the spring does the same thing, just more gradulally instead of like an on-off switch with the SSG.... You can further extend that reasoning to what is happening with the efficiency of the two systems when on the "knee" of the veloicyt vs. preload curve.... With a conventional setup, there is a slope to the efficiency, increasing as you decrease preload.... while with the SSG, it is pretty much either "efficient" (with a gap), or "inefficient" (without one)....
A telescoping stop rod would have to be structurally sound to resist the sudden stopping force at the bottom of the spring stroke.... If it could be done, then a good idea....
I think hard aluminum is certainly an option for the guide, as would be steel tubing, to save weight.... a tube with a bore 1/2 the OD saves 1/4 the weight but only loses a few percent of the strength....
I would think that you want the longest stroke possible in any PCP.... but then I dislike shortening the hammer stroke on any PCP except as a method of severe detuning for much lower pressures.... I think that is why the MRod has that feature....
Bob
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...................... You can further extend that reasoning to what is happening with the efficiency of the two systems when on the "knee" of the veloicyt vs. preload curve.... With a conventional setup, there is a slope to the efficiency, increasing as you decrease preload.... while with the SSG, it is pretty much either "efficient" (with a gap), or "inefficient" (without one)....
..................................
Bob
Bob, You hit the nail on the head with that brief summary. Very good.
Lloyd
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For those of you trying to wrap your brain around what is happening to the efficiency here, this drawing may help.... It is "generic", the numbers are ficticious (but representative), the purpose of the graph is to give you a visual comparision of how the various types of hammer spring setup affect the efficiency curves.... and then hopefully explain why they are the shape they are....
(http://i378.photobucket.com/albums/oo221/rsterne/Parts%20for%20Sale/Preloaded%20SSG_zpsxttcklco.jpg) (http://s378.photobucket.com/user/rsterne/media/Parts%20for%20Sale/Preloaded%20SSG_zpsxttcklco.jpg.html)
With a conventional, preloaded hammer spring, the spring is in contact with the hammer all the time, even when it is opening the valve.... It actually helps the hammer open the valve, and slows the poppet on the return trip.... In a stock Disco, for example there is about 1/4" of preload and the valve only opens 1/16-1/8".... As you increase the preload, the hammer spring holds the valve open longer and longer, and eventually you get to the point where the valve is still open after the pellet leaves the barrel, and the velocity no longer increases.... This is shown by the plateau in the velocity curve on the above graph.... As you continue to add preload, you continue to waste more and more air however.... The efficiency curve is typically a shallow "S" curve as shown....
If you use a shorter, stiffer spring, if it is adjusted for a gap between the spring and the hammer (let's say zero preload occurs at -3 Turns out from coil bind), from there and out, the gap means that the hammer spring is no longer pushing on the valve stem directly, it has "launched" the hammer, which then does all the work.... It is proven that this setup generally has less air-wasting hammer bounce, and better efficiency, providing there actually IS a gap.... If you increase the preload to where there is no gap, you can waste even more air than with a weaker spring, because the higher force can retard the valve closing even more.... However, for the way you would normally tune a gun, on the "knee" of the velocity curve, you tend to get better efficiency.... This setup, however, for a given average spring force, will be harder to cock, particularly at the end of the cocking stroke.... and it is still possible to get some hammer bounce, because the spring, when the hammer first strikes it, has by definition zero preload, and will give easily, storing some energy to be returned as hammer bounce....
With the SSG, when properly adjusted to have a gap between the end of the spring guide and the hammer when uncocked, the spring again does not push on the hammer while it is in contact with the valve, the hammer does all the work.... If you adjust the gap down to nothing, and then start adding preload, then there is a very large spring force against the hammer while it is opening the valve, which holds the valve open, wasting air.... The point where the gap reaches zero would be at -3 Turns out on the graph.... The velocity at which this occurs (the knee of the velocity curve) will depend on the amount of preload on the spring, and the average spring force available to launch the hammer.... You might gain a few fps by adding preload, but the amount of air wasted will NOT be worth it.... On the other hand, once there is a gap, the efficiency is very good, because the large amount of preload prevents the hammer, when it is thrown back by the valve on closing, from storing energy in the hammer spring which is then returned, causing air-wasting hammer bounce.... The gap acts very much like an "of-off" switch for the efficiency.... With a conventional setup, there is a slope to the efficiency, increasing as you decrease preload.... while with the SSG, it is pretty much either "efficient" (with a gap), or "inefficient" (without one)....
I hope this helps you understand why I'm so excited by this development....
Bob
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That was very helpful, Bob!! I am very excited to try this in my .25 pumper. 8)
EDIT: Mine will be hidden in the stock since my stock attaches directly to the main tube.
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I'm thinking this might make a BIG difference to the number of shots for the Millennium Pumper.... *grin*....
Bob
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I'm thinking this might make a BIG difference to the number of shots for the Millennium Pumper.... *grin*....
Bob
I bet it would!! Bob, your are a genius!!!
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because the large amount of preload prevents the hammer, when it is thrown back by the valve on closing, from storing energy in the hammer spring which is then returned, causing air-wasting hammer bounce....
Am waiting for another to ALSO try using a bumper to further mitigate bounce during the hammers return again wanting to bounce off end of stop rod.
Such as was done here ....
(http://i1320.photobucket.com/albums/u532/scott_schneider1/DSCF9922_zpsmnddec2a.jpg)
Guess if the basic rod with a gap STOPS BOUNCE DEAD there is zero need ... it is IMO of interest in the finer details if such a buffer in the system helps at all ???
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Agreed, should be simple to test with and without your O-ring buffer to determine if there is any difference.... I would suspect that at some values of preload (minimal) there could be a difference, while if the preload is higher there might not be.... ie it could affect the threshold where hammer bounce is completely eliminated.... Just a WAG at this point....
Bob
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...................... You can further extend that reasoning to what is happening with the efficiency of the two systems when on the "knee" of the veloicyt vs. preload curve.... With a conventional setup, there is a slope to the efficiency, increasing as you decrease preload.... while with the SSG, it is pretty much either "efficient" (with a gap), or "inefficient" (without one)....
..................................
Bob
the thing that is boggling is that it is such a simple concept; how is it they did not see it before you did? Not that expensive to implement in most of the pcp Platforms I would guess...
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"the thing that is boggling is that it is such a simple concept; how is it they did not see it before you did? Not that expensive to implement in most of the pcp Platforms I would guess."
Might be patented by another manufacturer. Might be other issues like reliability or some other liability issue too but I was thinking the same thing. The immense improvements would seem to be hard to overlook by engineering.
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because the large amount of preload prevents the hammer, when it is thrown back by the valve on closing, from storing energy in the hammer spring which is then returned, causing air-wasting hammer bounce....
Am waiting for another to ALSO try using a bumper to further mitigate bounce during the hammers return again wanting to bounce off end of stop rod.
Such as was done here ....
(http://i1320.photobucket.com/albums/u532/scott_schneider1/DSCF9922_zpsmnddec2a.jpg)
Guess if the basic rod with a gap STOPS BOUNCE DEAD there is zero need ... it is IMO of interest in the finer details if such a buffer in the system helps at all ???
I like anything that might dampen vibration in the shot cycle; matters more with an un-regged 50 fpe .25 heavy hammer Mrod than with a regged 14-18-20 fpe .177 light hammer Mrod... I would think?
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"the thing that is boggling is that it is such a simple concept; how is it they did not see it before you did? Not that expensive to implement in most of the pcp Platforms I would guess."
Might be patented by another manufacturer. Might be other issues like reliability or some other liability issue too but I was thinking the same thing. The immense improvements would seem to be hard to overlook by engineering.
Do know that most OEM rifle stocks tend to go along Monte Carlo grip design having ones thumb around wrist of stock. Such protrusion as a cocking indicator or stop rod clearly for most ... IN THE WAY !
Once you get some drop in stocks grip area more inherent to target stocks / thumb hole styles do you get clearance.
Also one must be aware ... GET A FINGER / DIGIT in the gap of stop rod to rear cap your going to get a NASTY finger wound !
* Ask me how I know ... ALREADY DONE IT & have nice blood blister on left corner of right thumb !! OUCH
So for liability of such, unless said SSG is fully covered or enclosed you gotta pay attention !
As too being missed in the design of manufacturers, The STOP ROD as an assembly is subjected to a pretty substantial shock upon every cycle. We at this point have no data on longevity or fatigue of parts.
As with much that gets designed, once engineers design it the Marketing and Lawyers get final word on what it becomes in the end. The 2 paragraphs above may Ying/Yang why we don't see such a devise being used on production air guns.
Just a WAG ... Lol
Scott
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I can imagine an alternative to the spring loaded rod arrangement would be an electric solenoid using a rechargeable battery pack. Bury solenoid in the back of the tube, put the battery pack in the stock and recharge it via standard micro USB port. What a rogue idea eh?
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If the engineering teams would have "considered" this option or known about the obvious upsides of the SSG, they would have incorporated it. My guess is that the solution is so deceptively simple that it has simply not been tried or developed.
The fact is, from an engineering standpoint, burying such a device in the rear of a pressure tube to make for a clean package (without anythin sticking out, is super simple.
The shock to the system is more than reasonable in over the counter airguns 10-30fpe, only when you go hogcrazy and want 90-160fpe do you get into territory where you need a looooot of air.
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I by the way am still lobbying for T.H.O.R. system maybe for the rear cocker (air hogs 90 fpe up) ;)
yep the heavy hammer rear cocker would have a significant pince hazard to it but for high fpe maybe worth it.
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Today I pulled apart my 2560 and fitted the SSG system to that.... Here is a photo of the gun before the SSG was fitted....
(http://i378.photobucket.com/albums/oo221/rsterne/22%20PCP/IMG_2840.jpg) (http://s378.photobucket.com/user/rsterne/media/22%20PCP/IMG_2840.jpg.html)
It is a twin to the 2260 I did earlier, except uses a 17 CI tank regulated at 1800 psi instead of a 13 CI regulated at 1600.... This allowed it to also get just over 4 magazines per fill (they are 8 shot mags) shooting 25.4 gr JSB Kings at an average of 949 fps with an ES of 9 and an efficiency of 0.96 FPE/CI for 35 shots.... The gun used a QB spring with a small amount of preload, and if turned up to 960 fps had audible hammer bounce and a decrease in shot count....
The SSG is very similar to the one on the 2260, with a 7/32" spring guide, but longer to accommodate the QB spring, so it projects further from the back of the main tube, just like the previous RVA does in the photo above.... This gun, even in the previous version (with the guide acting as a cocking indicator), requires you to lay your thumb along the side of the stock instead of wrapping it over the wrist, where it would be touched by the end of the guide when cocked.... I'm already aware of the ability to get pinched, anyone who has ever used a rear-cocker will have done it more than once, and learned to hold the gun accordingly.... In my new Monocoque PCP, it is buried DEEP inside the main tube, so not an issue.... It took a bit of playing on this gun to find the correct adjustments, but it was worth it.... I was rewarded with 50% more shots at slightly higher velocity.... I can now get 7 magazines (56 shots) averaging 960 fps (52 FPE) with the Kings, ending at 1400 psi with a 2% ES, with the first 52 shots within under a 1% ES (9 fps) ending at 1500 psi, which works out to 1.48 FPE/CI, over a 50% improvement.... I have gone from 4 solid magazine per fill to 6, without having to be at all concerned about the velocity dropping off, even with a 2900 psi fill, which is what I get with my Pony tank in the field.... The gun uses only 28 psi per 52 FPE shot....
Once again, I am astonished at the increase in shot count when operating on the knee of the curve by using the SSG.... As long as it has a gap to the hammer (this gun had 1 turn = 0.042"), the report is much quieter, just a clean SNAP, with no telltale BUURRRPPPP of hammer bounce.... Both of my Varmint rifles now have a 50% higher shot count than last year, 6 magazines instead of 4....
Bob
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Nice !! .... it does seem the heavy hammer / bounce prone systems are seeing the largest improvement.
Likely as talked about previous, due to closing valve no longer carrying hammer along with it.
Outstanding results indeed !
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On a Gen1 Marauder, you'll need to rest your thumb on the end of the bolt handle or risk the damage mentioned by Scott.
There is another spring energy sapping effect...you lose some of the spring mass kinetic energy as well. It looks like a 1/4" aluminum rod will do adequately for the spring holder. Thanks to Travis for showing the assembly with a nyloc/pem nut so there need only be one nut getting in on the spring energy division. Will need to counter hold the rod more tightly to set preload though...:)
cheers,
Douglas
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Douglas, I found that since I am retrofitting, and already know where the knee of the curve is, and therefore what velocity I am tuning for, I turn a shoulder on the back end of the rod (where the adjustment is in my case) and then use a single nut tightened against the shoulder.... I just sneak up on the required preload until I can get slightly more velocity than I want with a tiny gap, turning the shoulder a bit further down the guide at a time.... Most of the time you only need to vary the preload in increments of 0.1" (although the last adjustment sometimes I go half that).... Then all the final tuning is done with the gap adjustment only.... Once I find the tune I want, I cut the threaded end of the guide off flush with the nut, apply a drop of blue Loctite, and tighten the nut against the shoulder.... We'll see if it ever comes loose or sheds the nut over time....
Bob
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With Bobs permission Ive been given the go ahead to build a run of Sterne SSG for the Mrod. Im working on a commercial Sterne SSG right now and should work out all the bugs and have a protective cap also incorporated so as to protect ones digits.
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With Bobs permission Ive been given the go ahead to build a run of Sterne SSG for the Mrod. Im working on a commercial Sterne SSG right now and should work out all the bugs and have a protective cap also incorporated so as to protect ones digits.
What about a Sterne SSG for the Prod?
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With Bobs permission Ive been given the go ahead to build a run of Sterne SSG for the Mrod. Im working on a commercial Sterne SSG right now and should work out all the bugs and have a protective cap also incorporated so as to protect ones digits.
It looks like for an attempt at maximum output a 3" spring can be used in the Gen1. Can your design accommodate such a thing? This with MSC #: 06812234
cheers,
Douglas
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Next on the list will be the Prod.
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Next on the list will be the Prod.
That's good news!
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Douglas I'm using a smaller OD spring so it both fits threw the end cap and never touches the sides of the hammer. http://i.imgur.com/LeCpnrth.jpg (http://i.imgur.com/LeCpnrth.jpg) this is a cassette style that allows for easy spring changes.
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I've been using a large enough RVA bolt that I can change the spring from the back ever since I built my SECOND one in 2008.... It is just sooooooooooo much easier to not have to pull the end plug off the back of the gun.... With the SSG, they end up being a cartridge that just screws in, in one piece, with the preload already adjusted.... I'm guessing if you choose the correct length and wire spring, and get the preload so that it will reach the velocity plateau the gun is capable of.... all that will be needed will be to adjust the gap for different velocities by how deep you screw in the cartridge.... Travis, I think you have the right approach.... Are you going to make a screw-on cover that threads onto the end plug?....
Bob
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Im going to make a screw on half shell that covers the top of the SSG it will block any misplaced fingers but not require the stock be ground to fit so its reversable if one wants to sell their gun or put back to stock.
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Makes sense.... I just Googled Airgun SSG, and there are several hits on it on the various Forums I post on.... That didn't take long !!!
Bob
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A Russian airgun enthusiast created a piston gas/air version. Same exact idea of a free floating hammer.
http://forum.guns.ru/forummessage/25/1662795.html (http://forum.guns.ru/forummessage/25/1662795.html)
and a video: http://www.youtube.com/watch?v=JZ_a33EKxJk# (http://www.youtube.com/watch?v=JZ_a33EKxJk#)
The device is filled with an air compressor or a hand pump. A fill of 9psi gives you a pre load of 4kg or about 9lbs.
Due to Russian regulations on air guns (similar to UK regulations) he also added the "anti cop device" - a finger tight nut to quickly release the air pressure inside the piston and render the air gun inoperable.
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I don't understand a word of Russian, but it looks like he is using a small Gas-Ram.... It would work in the same way, providing it was adjusted to have a small gap with the hammer free floating.... We discussed this concept in the thread on the XS-60C PCP Repeater last July, which led me to building the first SSG for my Grizzly.... to emulate a Gas-Ram using a preloaded spring.... It all started here.... http://www.gatewaytoairguns.org/GTA/index.php?topic=59114.1040 (http://www.gatewaytoairguns.org/GTA/index.php?topic=59114.1040) with full credit to stalwart for asking the question in the first place.... Post #1047....
Bob
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Douglas I'm using a smaller OD spring so it both fits threw the end cap and never touches the sides of the hammer. http://i.imgur.com/LeCpnrth.jpg (http://i.imgur.com/LeCpnrth.jpg) this is a cassette style that allows for easy spring changes.
While looking at that picture I started to wonder, is that rod actually guiding the hammer as it goes - i.e. is it rigid enough to keep the hammer centered in the bore and thus giving you the zero fps spread?
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No its not rigid at all actually. I went first with a very rigid strait push SSG that ran in a tight bore but wasnt getting enough fps so I took the bushing out of the rod carrier and thats when my FPS came up and I started getting real good numbers. What I think is happening is that a hammer is held at the bottom by the sear and this cocks the hammer slightly down with the spring pushing from the center. By allowing the SSG to free fly and self align to the off center hammer it actually is faster and has less drag plus the hammer being cocked isnt putting a side load on the free floating rod. This of course is all conjecture and further testing needs to be done. I believe not having any spring contact on hammer walls and no contact of spring on spring adjuster allows the spring to function in a almost perfect state. So the only thing that can now effect velocity is fill pressure and hammer drag. I polished the hammer bore and lubed hammer to make it as close a constant as possible, so now we mainly have just fill pressure to deal with and because there is no hammer bounce and no spring drag the psi used per shot is very consistent thus the 5 shots in a row with no fps difference but that only happened once to be honest but still only seeing a few feet difference per shot in the sweet spot of the curve. More testing and more changes to SSG will help answer some questions I have now.
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By allowing the SSG to free fly and self align to the off center hammer it actually is faster and has less drag plus the hammer being cocked isnt putting a side load on the free floating rod.
I believe not having any spring contact on hammer walls and no contact of spring on spring adjuster allows the spring to function in a almost perfect state.
Yup, completely agree ;) ;)
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Yup, same here. Working on one of these for my 2240 I found that the rod was binding just slightly as it was an easy but minimally wiggly fit through the larger bolt. Running some 150-grit sandpaper on a rod through it on a drill for a little while opened the hole enough so it's still a decent fit, not sloppy, but slack enough that the tilt to the striker when cocked doesn't cause it to bind at all.
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Fantastic Gerard its nice to have data to back up a theory. I also found a slightly larger pin head on rod contacts lower on hammer forcing it up and strait into bore faster. Ill take pics Im not sure if im explaining it well.
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After threading the nut on the fixed end and peening it out, I ground the nut into approximately the same shape as the inside end of the Crosman hammer recess. So a very shallow cone. Wasn't trying for a super-exact fit or anything, it just seemed sensible that it should square up against the end of the hole more or less. A flat end makes sense to apply to different shaped holes in different hammers.
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Something that may be relative to keeping hammer traveling straight and true in spite being held at full cock tilted.
BY PUSHING ON IT on the broadest diameter practical, which would be very close to the spring bore diameter of the hammer.
Once hammer released the push of the spring VIA THE STOP RODS END is full perimeter and NOT just a central contact point.
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Ok so imagine striker rod inside bore of hammer as you can see if the hammer is cocked slightly down in the bore by the sear the contact spot will be low on wide head of striker forcing it to become concentric to bore http://i.imgur.com/1nbJJw3h.jpg (http://i.imgur.com/1nbJJw3h.jpg) like this http://i.imgur.com/SC6aCKxh.jpg (http://i.imgur.com/SC6aCKxh.jpg) thus less drag on hammer down bore. with stock spring set up the spring just deflects more causing more cocking and more spring drag.
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What you need to keep mind of is that spring directly IS NOT DRIVING THE HAMMERS MOTION .... The end or Hat of stop rod is.
If Hat and rod are rigid traveling in alignment with hammer bore within main tube the only cant spring can have is some side to side motion. By virtue of Hat & rod traveling straight and true having contact between hat and hammer on a large contact diameter, once hammer is released the force across there contact point squares them up and propels them as one towards poppet stem with minimal or any tilt present.
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After threading the nut on the fixed end and peening it out, I ground the nut into approximately the same shape as the inside end of the Crosman hammer recess. So a very shallow cone. Wasn't trying for a super-exact fit or anything, it just seemed sensible that it should square up against the end of the hole more or less. A flat end makes sense to apply to different shaped holes in different hammers.
I'm wondering if a delrin nut at the rear cap would withstand the forces here, it would provide much less friction.
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I dont use a delrin cap. But I am using a delrin stop nut. And it works good.
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By allowing the SSG to free fly and self align to the off center hammer it actually is faster and has less drag plus the hammer being cocked isnt putting a side load on the free floating rod.
Does this mean you are running your SSG without an insert in the gun's end cap to keep the rod centered?
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Pictures of mine, with the delrin stop plug on my Discovery.
(http://i54.photobucket.com/albums/g97/renderbrandt/20151228_162816.jpg)
(http://i54.photobucket.com/albums/g97/renderbrandt/20151228_171848.jpg)
I realized the cocking effort was suffering a little bit since I used to use the end of the rear tube for my thumb leverage. Which I fixed by making a thumb recess:
(http://i54.photobucket.com/albums/g97/renderbrandt/20151229_122038.jpg)
Ps. Before anyone asks, the thing on the cocking bolt is an spring loaded adjustable depth pellet seater.
The first prototype of this can be seen here: http://vid54.photobucket.com/albums/g97/renderbrandt/20150704_205527.mp4 (http://vid54.photobucket.com/albums/g97/renderbrandt/20150704_205527.mp4)
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I use a rounded end on my guide rod to allow it to find it's own angle with the hammer, regardless of the shape of the bottom of the hole in the hammer.... It is important not to have too close a fit between the guide rod and the gap adjusting nut which keeps it straight in the tube.... I had one with a 3/16" rod (0.188") running in a 0.191" hole and it had drag and I had to drill it out to 0.194".... the gun picked up 150 fps once the drag on the rod was eliminated....
Bob
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Exactly right Bob. Half of why it works so well is limiting drag on the hammer walls and spring adjuster. Use smaller spring to bore than stock to elimate any contact possible.
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Exactly right Bob. Half of why it works so well is limiting drag on the hammer walls and spring adjuster. Use smaller spring to bore than stock to elimate any contact possible.
Lol ... or a Nylon hammer ... or lined spring bore than really has so little drag ;)
Guess I'm blind to issues you guys are seeing running steel hammers within steel tubes with steel springs on steel guides. DRAGGY NO DOUBT !!
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Even with a Nylon hammer I still wouldnt want any part of the spring or guide touching the sidewall if it can simply be designed around, no need to introduce any friction at all if it can easily be avoided.
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Mine had "tight" clearance when I started, but realized quickly there were to much friction in various places. So I reamed out the hammer, turned the head of the guide round-ish and enlarged the hole in the rear cap so the guide could freefloat the way it wants.
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Tomg thats exactly how im doing it now and is giving me the best results so far.
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So does the SSG require an insert to keep the rod centered, say in an Mrod which already has an open end cap? Ya'll are losing me a little bit when talking about letting the rod free fly.
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Whether or not one uses a low-friction insert, some slop should probably be built into the fit owing to the somewhat wiggly fit of the striker/hammer and its tendency to start off at a slight angle. The sear holding it at one edge forces the spring to cant the back end the opposite way. I found that with too snug a fit on the guide rod it would jam for a moment, sometimes even causing delayed firing by a second or more. This was a smooth fit, easy to slide by hand, but under cocked angular strain was jamming. A couple or a few thousandths ought to be plenty.
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I don't want any interference anywhere.... My hammer ID on the new Monocoque is 1/2" with a 3/8" spring.... Drilled hole (tapered end) with a rounded end on the guide that self-centers.... and NO contact between the guide and hammer once it stops.... I am less concerned with a close fit between the guide and the adjusting bolt is slides through, I would like the hole to keep the guide centered in the hammer.... but not to the point of being draggy.... It does, after all, have 5-15 lbs. of force pulling it forward during firing.... pulling, not pushing, so very unlikely to bind, providing there is a few thou clearance.... I don't see anything wrong with a bit of lube on the spring/guide either.... I used a couple drops of oil with 10% Moly in it....
Bob
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I am making the stationary nut/stop from Bronze. AL for the rod...either moly grease or 2C45 Krytox should do the job keeping it slippery. Or maybe slide in a PEEK bushing...:)
cheers,
Douglas
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I didn't say I was going to convert EVERY PCP I have.... *LOL*.... Yes, the AT-44 could be quite a challenge, and since it already has an anti-bounce device, may not be worth it....
Bob
Bob,
I have my AT-44 apart right now, and just realized there is about 3/16" travel from where the hammer rests on the valve to the hammer stop screw. That means the hammer is moving the valve pin about 3/16" before hitting the hammer stop screw, right? If that is the case, then I would think there is definitely a good possibility of bounce happening? With the pre-load the hammer is just leaning on the valve pin unless cocked, so that tells me the valve would be giving the hammer a good whack when it closes. I'm not sure on what the best approach would be on this, but it would seem there is room for improvement with some sort of SSG type device. What do you think?
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A little more work done today between jobs. http://i.imgur.com/uxOLtZch.jpg (http://i.imgur.com/uxOLtZch.jpg) http://i.imgur.com/4DzU43Ah.jpg (http://i.imgur.com/4DzU43Ah.jpg) http://i.imgur.com/V5ZEyczh.jpg (http://i.imgur.com/V5ZEyczh.jpg)
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So you are saying, Donny, that the AT-44 hammer can rebound 3/16" before hitting the Wishbone?.... Yes, that is enough to store enough energy in the spring to get air-wasting bounce, IMO.... Likely that is the reason the Hatsan is no better for efficiency than a PCP without the anti-bounce device and a similar tune.... In addition, with preload against the hammer when on the valve stem (and increasing while travelling that 3/16") the wishbone may just be causing the hammer to reverse sooner, and then it is still driven by the spring back to the valve.... I'll have to wait until I can pull mine apart to comment, but I hope to come up with an SSG to work in mine....
Travis, I see the lock screw for the adjusting barrel.... How do you turn that barrel, just by using the Nyloc preload adjuster?.... I know I just wind mine down with my fingers until I feel it touch, check the velocity, and if it's too low I add preload and try again.... Once it's a fraction more than I want, then I leave the preload alone and increase the gap to drop the velocity to what I need.... I have a hex on the end of my bolt, so even with the lock screw tight on the plastic plug that acts as a brake, if I need to adjust it I can use a wrench.... You won't have that option, I don't think, you will have to back off the lock screw each time....
Bob
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I can adjust the barrel by hand just by turning the lock nut with my fingers after loosning the set screw next ill put a groove on end of rod above nut to insert a flat blade screwdriver so one can adjust preload nut. Very simple really.
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So when a hammer has a throw length adjuster like in the MRod - what do you do? cut it short?
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So you are saying, Donny, that the AT-44 hammer can rebound 3/16" before hitting the Wishbone?.... Yes, that is enough to store enough energy in the spring to get air-wasting bounce, IMO.... Likely that is the reason the Hatsan is no better for efficiency than a PCP without the anti-bounce device and a similar tune.... In addition, with preload against the hammer when on the valve stem (and increasing while travelling that 3/16") the wishbone may just be causing the hammer to reverse sooner, and then it is still driven by the spring back to the valve.... I'll have to wait until I can pull mine apart to comment, but I hope to come up with an SSG to work in mine....
I completely overlooked the wishbone! I need to go back and look at that. I don't know that it makes a difference with my observations though? Your point about it may very well be the case too, allowing the hammer to rebound faster. Either way, I can see the chance for bounce, especially given the high amount of preload when shooting at 50+fpe. I know that poor little stop screw is getting flattened and bent on my gun, and I can see it getting replaced in the future.
Now, if there was a way to turn that wishbone into some sort of a simple ratchet/catch that would only engage after valve strike, that would do the trick, with no changes in the spring required. Hmmm... You just gave me another thing to think about :)
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I can adjust the barrel by hand just by turning the lock nut with my fingers after loosning the set screw next ill put a groove on end of rod above nut to insert a flat blade screwdriver so one can adjust preload nut. Very simple really.
So you are depending on a "no slip" condition between the center guide, spring, and barrel to adjust the barrel?
Can you be sure of this at all times?
Will you provide an indicator (a milled mark) on the barrel edge to gauge the changes (by the clock)?
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A milled mark or marks would be easy to do and yes it moves easily because the carrier for the rod and spring is under tension by the spring and adjusting nut and acts like a single unit at rest. Its really simple in design and I like that.
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If you are using a plastic plug for the brake, you may find it conforms to the threads and you may not be able to turn the barrel by hand.... just something to watch for....
Bob
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If it always moves as a unit then there is no need for a mark - the position of the nut will do fine.
Just checking the "no slip" condition.
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So when a hammer has a throw length adjuster like in the MRod - what do you do? cut it short?
Yup, cut my striker/stroke screw to have @ 5/16" of thread, then with a hacksaw blade place a shallow cut to act as a screwdriver slot.
* Adjust cut length to be flush or less within hammers spring cavity.
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Had to join the party. Haven't had a chance to tune yet but will get a chance later on this morning. Worked well with the SSG hidden in the stock . I had to hollow out the stock a bit for clearance and you can see in the pics that it works perfect for a cocked indicator. The gun in pic is regulated to 1200 psi and due to the hammer bounce I could not cure for the life of me could only get 60 shots at 770 fps . Pretty confident this will take care of it.
http://i1138.photobucket.com/albums/n538/hobbyman2007/image_3.jpeg (http://i1138.photobucket.com/albums/n538/hobbyman2007/image_3.jpeg)
http://i1138.photobucket.com/albums/n538/hobbyman2007/image_2.jpeg (http://i1138.photobucket.com/albums/n538/hobbyman2007/image_2.jpeg)
http://i1138.photobucket.com/albums/n538/hobbyman2007/image.jpeg (http://i1138.photobucket.com/albums/n538/hobbyman2007/image.jpeg)
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That is a perfect way to make it invisible! Very close to what I have in mind for my P-Rod.
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Dropped in the RSTERNE SSG made NO adjustments and ran a string. As you can see there is room for improvement but FAR better than stock by a long shot. This is a bone stock Marauder .25 with SSG only. Created: 01/08/16 12:00 PM
Description: Sterne SSG
Notes 1: all stock .25 marauder
Notes 2:
Distance to Chrono(FT): 2.00
Ballistic Coefficient: 1.000
Bullet Weight(gr): 25.40
Temp: N/A °F
BP: N/A inHg
# FPS FT-LBS PF
50 ERROR 3
49 792 35.38 20.12
48 786 34.85 19.96
47 794 35.56 20.17
46 796 35.74 20.22
45 797 35.83 20.24
44 801 36.19 20.35
43 802 36.28 20.37
42 797 35.83 20.24
41 803 36.37 20.40
40 806 36.65 20.47
39 800 36.10 20.32
38 801 36.19 20.35
37 811 37.10 20.60
36 807 36.74 20.50
35 818 37.74 20.78
34 812 37.19 20.62
33 809 36.92 20.55
32 812 37.19 20.62
31 815 37.47 20.70
30 811 37.10 20.60
29 810 37.01 20.57
28 ERROR 3
27 813 37.28 20.65
26 ERROR 3
25 810 37.01 20.57
24 818 37.74 20.78
23 ERROR 3
22 817 37.65 20.75
21 810 37.01 20.57
20 815 37.47 20.70
19 811 37.10 20.60
18 811 37.10 20.60
17 ERROR 3
16 818 37.74 20.78
15 ERROR 3
14 813 37.28 20.65
13 818 37.74 20.78
12 817 37.65 20.75
11 818 37.74 20.78
10 808 36.83 20.52
9 811 37.10 20.60
8 802 36.28 20.37
7 799 36.01 20.29
6 809 36.92 20.55
5 799 36.01 20.29
4 808 36.83 20.52
3 804 36.46 20.42
2 803 36.37 20.40
1 792 35.38 20.12
Average: 806.9 FPS
SD: 8.2 FPS
Min: 786 FPS
Max: 818 FPS
Spread: 32 FPS
Shot/sec: 0.1
True MV: 807 FPS
Group Size (in): 0.00
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The es between shoot 2 and 47 is great for an unregulated gun.
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If you give us the fill and refill pressure, we can calculate an efficiency.... It looks like the string was 50 shots averaging 36.7 FPE = 1837 FPE total.... The MRod reservoir holds 215 cc = 13.1 CI, so all we need is the pressure drop over the string....
Bob
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2900-1850
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Holy smokes. Had to take a bit of a trip to find a suitable spring ,the one I had was a bit too short. Once reassembled ,got 80 shots from 2800psi to 1200psi @750 fps. For an eff. of 1.26 . Although not stellar and can probably squeeze a bit more out of it , I am extremely happy with the results. I'm going to go on a limb and say this is a true breakthrough for the airgunning world. Now to figure out how to get rid of the hammer bounce in my .357 homebuild.
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Dropped in the RSTERNE SSG made NO adjustments and ran a string. As you can see there is room for improvement but FAR better than stock by a long shot. This is a bone stock Marauder .25 with SSG only. Created: 01/08/16 12:00 PM
Description: Sterne SSG
Notes 1: all stock .25 marauder
Notes 2:
Distance to Chrono(FT): 2.00
Ballistic Coefficient: 1.000
Bullet Weight(gr): 25.40
Temp: N/A °F
BP: N/A inHg
# FPS FT-LBS PF
50 ERROR 3
49 792 35.38 20.12
48 786 34.85 19.96
47 794 35.56 20.17
46 796 35.74 20.22
45 797 35.83 20.24
44 801 36.19 20.35
43 802 36.28 20.37
42 797 35.83 20.24
41 803 36.37 20.40
40 806 36.65 20.47
39 800 36.10 20.32
38 801 36.19 20.35
37 811 37.10 20.60
36 807 36.74 20.50
35 818 37.74 20.78
34 812 37.19 20.62
33 809 36.92 20.55
32 812 37.19 20.62
31 815 37.47 20.70
30 811 37.10 20.60
29 810 37.01 20.57
28 ERROR 3
27 813 37.28 20.65
26 ERROR 3
25 810 37.01 20.57
24 818 37.74 20.78
23 ERROR 3
22 817 37.65 20.75
21 810 37.01 20.57
20 815 37.47 20.70
19 811 37.10 20.60
18 811 37.10 20.60
17 ERROR 3
16 818 37.74 20.78
15 ERROR 3
14 813 37.28 20.65
13 818 37.74 20.78
12 817 37.65 20.75
11 818 37.74 20.78
10 808 36.83 20.52
9 811 37.10 20.60
8 802 36.28 20.37
7 799 36.01 20.29
6 809 36.92 20.55
5 799 36.01 20.29
4 808 36.83 20.52
3 804 36.46 20.42
2 803 36.37 20.40
1 792 35.38 20.12
Average: 806.9 FPS
SD: 8.2 FPS
Min: 786 FPS
Max: 818 FPS
Spread: 32 FPS
Shot/sec: 0.1
True MV: 807 FPS
Group Size (in): 0.00
Amazing - Probably this will be the most interesting and advancing PCP mod of 2016.
Any pics and specs of your contructed SSG? I'd really like to build one for my brothers .25 Synrod.
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So the pressure drop is (2900 - 1850) = 1050 psi (72.4 bar), and the total air used is 72.4 x 13.1 = 949 CI.... That works out to 1837 / 949 = 1.94 FPE/CI.... That is one of the highest efficiency numbers I have ever seen.... The gun didn't have a reservoir extension or anything, did it?.... just a stock MRod reservoir, and you are sure about the pressure drop?.... If so, just WOW !!!
Bob
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For me personally as a tuner this is huge!!! It will save me hours a day finding a curve for my customers different power requirements. This was a strait drop in with NO adjustments just to see if a commercial unit could be preset to give a decent string. And am I happy YES!!!
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Bob its bone stock in every way! Only thing I did was replaced striker in hammer with a set screw and add SSG period. My digital pressure gauge is on the money.I have quite a sweet set-up for tuning ill post pics.
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Looks like you nailed it, for a 37 FPE tune.... Perhaps I shouldn't be too shocked, as that is really pretty mild in .25 cal.... I wonder what you will get when you crank it up to 45 FPE.... or 50-55 FPE.... *grin*.... I got 1.48 FPE/CI with a 52 FPE tune in my 2560 regulated at 1800 psi, so who knows?.... Should in theory do better than that unregulated, because of the higher pressures....
Bob
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Agree ... that is incredible efficiency & number of shots
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Ill mess with higher tune tonight all i was after today was seeing how a drop in SSG would fair. This would be a great tree squirrel tune though.
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That is an amazing shot string Old Pro!! 8)
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I took apart my Hatsan .25 cal AT-44 Long today to have a look and do some measurements.... The spring is slightly longer and smaller wire than that in a QB.... It is 2.5" long, made from 0.043" wire, and the rate is almost 13 lb/in.... What shocked me was the amount of preload it was under.... This gun is tuned currently to shoot 36 gr. Daystates at 950 fps (72 FPE average), and it gets 9 shots within a 2% ES and 12 shots within 4%.... at an efficiency of 1.15 FPE/CI.... It shoots JSB Kings at 1070 fps (haven't yet tried the Heavies).... The preload is set to 9 turns out from zero (where the gun was when stock).... That works out to 0.70" of preload (nearly 9 lbs.) and the hammer stroke is only 0.47", giving a total compression of 1.17" (nearly 15 lbs.).... This means that the spring is pushing very hard on the hammer during the shot, helping to open the valve, and slowing it's closing, and therefore a lot of the dwell is coming from the spring.... I have my doubts if I will be able to fling the hammer at the valve hard enough to get the required dwell without the spring helping it....
In addition, there is a large 1.9" long plastic plug in the rear of the tube.... It holds the trigger group, the safety mechanism, and the spring for the wishbone anti-bounce device.... Removing it would allow tons of room for an SSG to be completely contained in the tube, providing you can still mount the trigger and safety.... I'm going to have a close look to see if I can figure out a way to try an SSG without destroying parts needed to return the gun to the way it is now....
Bob
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I am guessing the noise level dropped a bunch! Would this work even better on a lower fill psi gun like a Discovery?
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It would work great on a disco or any spring feed hammer with dump valve in my opinion. I dont have a disco here but when I get one I will set off to building one like the Mrods.
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It works great on my disco (albeit I got a bunch of other changes) but I have to deal with the small diameter tube and stock valve.
And I got excellent results by just dropping it it in.
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Hey guys,
I don't want to sound like a skeptic, because frankly, I don't know ???.
But my gut just can't buy an efficiency of 1.94 FPE/CI without the SSG/gun being fined tuned :P.
That said, I will likely be adding this mod to most of my PCP's ;).
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Built the first SSG and have it in my personal gun then built the second with specs from first and dropped it in new gun off the shelf. Never touched a thing BUT in my gun it was shooting in the mid 850s so It does need to be tuned to get the power to a more usable speed. The point is that it can be replicated easily and very little tuning needed to get it where it needs to be. Its good to be skeptical I am the biggest skeptic of all believe me.
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I had a good look at the Hatsan.... First of all, there is a 5.5mm hole straight through the middle of the plastic rear plug.... A 7/32" guide rod is a perfect sliding fit, and fits inside the hammer spring as well.... so that could work as a guide.... The trigger assembly JUST clears the hole, so you cannot enlarge the hole to take the spring out the back through the plug.... the trigger is unfortunately in the way.... Any changes to the SSG will require pulling the gun apart and pulling the hammer out the front, OR pushing the trigger pins out, and if you have ever had a Hatsan trigger off, I doubt you want to do that 20 times, you need a special pin to hold the sear in place that you push out when installing the front locating pin.... While I had it all apart, I shortened the top of the safety lever to eliminate the auto safety, which I hated.... I pulled out the hammer preload adjusting screw, and it is 8mm x 1.25 mm pitch, so each turn adjusts the preload 0.0493", call it 50 thou.... The minimum preload is about 1/4", and my 9 turns added 0.45", for the total of 0.70" I measured before.... The small spring spacer with the hole in it is about 0.150" thick (part of that 1/4" of preload), and it, or the spring, won't fit into the threaded portion in the front of the hammer.... There is enough room under where the safety sits to cut away some material from the top of the plastic plug (the part that sticks out above the stock) to allow for the stop nut on the guide, and you could cut a larger slot in the top of the stock (where the slot was needed to miss the hammer adjusting allen key) also.... Therefore, I think the external part of the guide and stop nut, that slides back and forth during cocking, can have a place to live.... under the safety....
My thoughts at the moment are to use a spring guide with the typical peened and shaped nut at the front of spring OD, and threaded at the back for 10-32 nuts, and create the necessary clearance in the back of the plug and stock for them to move during cocking.... The stop nuts will hit the back of the plastic block (with an O-ring cushion), but there will NOT be any adjustment for the gap at the back.... I will try and guess/calculate some combination of spring length and preload that might work, with the original hammer preload adjusting screw all the way forward in the hammer.... I will aim for a bit less preload than I will probably need.... Assuming it turns out that the idea works, but the velocity is low, I will pull it apart, increase the preload by 0.10", and screw the old hammer screw out 2 turns to compensate, using it as a gap adjuster.... Hopefully I will find a setting that works, if not I will try a stiffer spring and repeat the procedure.... I hope I can get the SSG to work before the gun gets impossible to cock.... I guess we'll see....
Bob
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I was looking at my AT44 to Bob and it looked like a lot of work to be sure but then my squirrel got on the wheel and started running and I think We could build a plug in the back to make a really long rod that went past all the stuff inside and had the SSG bolted to the outside.
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I had the same reaction, first glance I thought no-go.... but now I may have a solution with little work.... The problem is the lack of exterior adjustability, which may require something like you are suggesting.... I know what I want for a tune, and I don't mind taking the gun apart numerous times to get it, but it would not be for everyone....
Bob
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I double checked my measurements, chucked the rear block in the lathe, and using 5/16", 3/8" and 7/16" end mills gradually opened up the recess in the bottom of the overhang of the rear block to miss the 10-32 stop nut.... Here is a photo of it....
(http://i378.photobucket.com/albums/oo221/rsterne/Hatsan%20AT44-10/Hatsan%20Rear%20Block%20for%20SSG_zpsmvmcw7k6.jpg) (http://s378.photobucket.com/user/rsterne/media/Hatsan%20AT44-10/Hatsan%20Rear%20Block%20for%20SSG_zpsmvmcw7k6.jpg.html)
You can see that the nut will just clear, and it has about 5/8" or movement available before it will hit he safety button, so it won't interfere, there is even enough room for an O-ring, and in fact you won't even see it.... I haven't carved out the stock yet, but a Dremel will look after that....
Bob
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I had a good look at the Hatsan.... First of all, there is a 5.5mm hole straight through the middle of the plastic rear plug.... A 7/32" guide rod is a perfect sliding fit, and fits inside the hammer spring as well.... so that could work as a guide.... The trigger assembly JUST clears the hole, so you cannot enlarge the hole to take the spring out the back through the plug.... the trigger is unfortunately in the way.... Any changes to the SSG will require pulling the gun apart and pulling the hammer out the front, OR pushing the trigger pins out, and if you have ever had a Hatsan trigger off, I doubt you want to do that 20 times, you need a special pin to hold the sear in place that you push out when installing the front locating pin.... While I had it all apart, I shortened the top of the safety lever to eliminate the auto safety, which I hated.... I pulled out the hammer preload adjusting screw, and it is 8mm x 1.25 mm pitch, so each turn adjusts the preload 0.0493", call it 50 thou.... The minimum preload is about 1/4", and my 9 turns added 0.45", for the total of 0.70" I measured before.... The small spring spacer with the hole in it is about 0.150" thick (part of that 1/4" of preload), and it, or the spring, won't fit into the threaded portion in the front of the hammer.... There is enough room under where the safety sits to cut away some material from the top of the plastic plug (the part that sticks out above the stock) to allow for the stop nut on the guide, and you could cut a larger slot in the top of the stock (where the slot was needed to miss the hammer adjusting allen key) also.... Therefore, I think the external part of the guide and stop nut, that slides back and forth during cocking, can have a place to live.... under the safety....
My thoughts at the moment are to use a spring guide with the typical peened and shaped nut at the front of spring OD, and threaded at the back for 10-32 nuts, and create the necessary clearance in the back of the plug and stock for them to move during cocking.... The stop nuts will hit the back of the plastic block (with an O-ring cushion), but there will NOT be any adjustment for the gap at the back.... I will try and guess/calculate some combination of spring length and preload that might work, with the original hammer preload adjusting screw all the way forward in the hammer.... I will aim for a bit less preload than I will probably need.... Assuming it turns out that the idea works, but the velocity is low, I will pull it apart, increase the preload by 0.10", and screw the old hammer screw out 2 turns to compensate, using it as a gap adjuster.... Hopefully I will find a setting that works, if not I will try a stiffer spring and repeat the procedure.... I hope I can get the SSG to work before the gun gets impossible to cock.... I guess we'll see....
Bob
Thank you guys for humoring me on the AT-44! I had mind apart as I mentioned earlier. Like you, I realized that thing uses a lot of pre-load. My whole "hammer with suspension" idea could possibly work on a gun with a different layout, but it ain't gonna happen on this gun. I just can't find the room without major modification.
I did find a very simple solution for it if you're shooting with lower spring settings, like I do with my regulated cylinder though! I'm not sure what the turns out from minimum it would be on a regular gun, because I added a "stopper" in front of the adjustment screw in the hammer so I wouldn't have to go so many turns in to figure out where I had my spring at. With that in mind, I have MY adjustment at 1.5 turns out to shoot the JSB 18.1s at 915fps(I'm just guessing that would be 5-6 turns out if it weren't modified). I looked while it was apart to see how close the hammer was getting to the brass fitting the valve assembly screws into. The hammer is getting pretty close, it is hitting the stop screw. In other words the large outer part of the hammer that rides in the trigger tube is getting about the diameter of the stop screw from the face of the brass fitting. On a quick whim, I took a piece of silicon fuel tube from a nitro rc car and made a loop between the hammer and the brass fitting the air cylinder screws into. It doesn't interfere with the part of the hammer that actually hits the valve pin. It isn't a complete loop to allow for the stop screw. This quietened the gun down, and I looks like it will get me a few more shots by looking at the gauge. The guns was quieter, and the velocity was only down about 5-10fps, and it appeared that I only used about 30-35 bar on 20 shots. Normally it would have been down 40-50 bar after 20 shots. I could be imagining things too :D That fuel tubing is about 5-6 mm in diameter and pretty stiff, and it ain't going anywhere, I checked to make sure.
It made zero difference on the high spring settings with my unregulated "beast mode" cylinder(short), which I didn't really expect it to. That is when the gun really suks down the air, and where I wanted to see if I could make the real improvements. I have gotten it to shoot as high as 990fps with the JSB 25s, but that is ultimate air waste for 6-7 loud shots,lol! I can get about 12-13 shots with a decent ES shooting in the 950fps range, or 15 shots in the 930fps range as it is. It gets pretty loud when the pressure gets below 150 bar, so I know it is dumping a lot of air at that point. I know you guys are thinking I need to stop trying to make my .22 a .25, but it is just an exercise in seeing what the gun is capable of :D I know the gun is capable of 55+fpe , but it isn't feasible with that kind of air use. Anything much over 50fpe is just loud and wasting air. I'm watching your progress like a hawk :)
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So you are using a rubber buffer between hammer and valve, similar to a bstaley O-ring buffer....
Bob
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So you are using a rubber buffer between hammer and valve, similar to a bstaley O-ring buffer....
Bob
Yep, I guess you could say that. I am not familiar with with the bstanley o-ring buffer? Remember, I'm a newb :( I guess the biggest difference is that the fuel tubing is hollow, so it will give more than an o-ring probably. Does my quick crappy diagram make sense?
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I had a write up in the euro board on how to mod a AT44 for and adjustable oring buffer mod but not sure how to find it, It has pics and descriptions.
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This going to change tuning on airguns by leaps and bounds, will never be the same again imop. Just like Bob says WOW!!! David
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At some point in the R&D of the SSG this needs to happen ...
1) Do we need a heavy poppet spring any longer or will a light one allow faster valve opening ?
2) What changes will happen with Heavy to Light hammer weights ?
3) Given spring energy is sufficient to throw weight of hammer used, does a Highly pre-loaded soft spring really operate differently than a stiffer spring with less pre-load ?
4) Does application of a buffer between spring cavity and end of SSG further reduce vibration or bounce ?
This is very exciting but so far in testing appears to be placing PCP valve / hammer tuning of past on the pages of history for many AG designs that can incorporate the mechanics needed to use the SSG devise ???
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Yep, just like the bstaley mod, except he uses a stack of (usually 3) 70 Durometer (sometime 90D) O-rings.... Search "bstaley mod" and you will find lots of details on how it works and how to tune it.... To really take advantage of it, you need an adjustable length nose on the striker like the MRod or PRod....
Bob
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You could be very right David...I admit to being more than a little intrigued by the idea.
Spent a little time flushing out my quick sketch...thinking to slab side the striker (two sides), the larger diameter portion of the guide rod and the follower (three sides) to allow air movement. Bushing at rear will adjust via pin spanner, guide rod via hex grub screw. Likely use 3/8-24 and 1/4-28 for threads, maybe inset some nylon beads in threads to provide adjustment stability.
Likely still some fine tuning, but should be close...
(http://i245.photobucket.com/albums/gg76/gippeto_album/22xx%20ssg_zpsmemat27u.jpg) (http://s245.photobucket.com/user/gippeto_album/media/22xx%20ssg_zpsmemat27u.jpg.html)
Another for the project list, thanks Bob. 8)
Al
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Good questions, Scott, and more research will give more definitive results.... I can give my opinions, based on current data....
1. I would guess that a lighter valve (poppet) spring can be used, particularly in a regulated PCP.... There may still be a case for a heavier one in unregulated ones, because it evens out the total closing force over a wider pressure range.... and in theory can extend the shot string.... The bstaley mod, which effectively acts like a very stiff, progressive valve spring may or may not provide as much benefit, or could work even better, I have no idea.... There is also the possibility that the SSG may extend the shot string of an unregulated PCP over a wider range of pressures, or maybe not, too early to know....
2. My gut feel about hammer weights is that really light ones may not show as much benefit from the SSG, and in fact may not work as well because the guide becomes a larger percentage of the total weight accelerated by the valve.... On the other hand, once the hammer spring is no longer leaning on the hammer during the shot cycle, dwell should decease for a given lift (hammer energy), which is EXACTLY what happens when you use a lighter hammer with a conventional spring setup.... This should result in better efficiency, by using shorter sips of higher pressure (the pressure having less time to decay because of the shorter dwell).... This effect is added to the elimination of hammer bounce, which I think is the main benefit....
3. Good question, and since preload against the hammer DURING the shot cycle is no longer part of the equation, it should be that ONLY the hammer velocity at valve contact (and the hammer weight), and hence the hammer energy, make any difference to velocity and efficiency of the shot cycle itself.... What you do before flinging the hammer at the valve should NOT affect the results.... as there should be no difference in the hammer energy from a given hammer travel if you use a short, stiff spring or a long, weak one.... In theory, it should be the AVERAGE spring force (in lbs.), times the distance (in ft.) the guide moves during acceleration (as FPE = ft.lbs.) that determines the hammer energy.... Preload of zero and cocked force of 20 lbs.... preload of 5 lbs. and cocked force of 15 lbs.... and preload of 8 lbs. and cocked force of 12 lbs.... all have an average force of 10 lbs. and should produce the same hammer velocity, providing the travel distance from sear release to the guide stopping is the same.... Obviously, however, the one with the greater preload and lowest cocking force would be much nicer to cock.... and in the case of a short, stiff spring with zero preload, the SSG may not absorb all the valve closing energy given back to the hammer and you could still get hammer bounce.... Each gun will have a minimum preload requirement to eliminate hammer bounce.... Whether that minimum changes as the pressure drops (and which way) is still undetermined....
4. I haven't a clue if a buffer in the hammer cavity (or as was suggested a fluid camber) makes any difference to the final operation of the SSG.... either good or bad....
Bob
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Al, that looks great!.... Inner thread (on guide rod) sets the preload, and outer thread (on barrel) sets the gap, correct?.... What is the "thermometer shaped" area on the side of the guide?.... and BTW, why should you not get to benefit from yet another project to add to your list.... *LOL*....
I really like the concept that the guide is not moving, and hence not wasting spring energy.... The only wasted energy is on the small ring (follower), and that is tiny.... Do you think the design will require a fairly stiff spring to get enough hammer energy in that length?.... I assume that is a Disco/22XX you have drawn?....
Bob
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Just a small update as I wanted a little more room for a longer spring, so I made the rear cap a little longer.
I have yet to thread the cap so to adjust the preload on the spring. I did however make a flat acetal floating disc so I can use two springs and have them be squared up (I didnt have a long enough spring...)
(http://i54.photobucket.com/albums/g97/renderbrandt/20160109_113529.jpg)
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You can just butt the springs up against each other, providing the coils are closed up, they won't wind into each other.... no need for the disc (although it won't hurt)....
Bob
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I had to cut one of the springs a little shorter, so it wasn't closed up.....
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Thanks Bob...all correct as to function.
Used an existing drawing (22xx) to get things to scale and save a little time...thermometer shape is the cutout for striker pin. Spring could be an issue...~5/8" room with striker butted up to tube plug...1.25" at rest but pre-loaded. Will have to see what I have when the time comes. 13/22xx sear spring comes to mind...
Should be able to get more room if needed by drilling the striker through and adding a striker plate to valve stem similar to the BT65. Everything is a trade off hmm? ;)
Al
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how about using a multirate spring or 3 springs with the spacer each progressively stiffer?
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how about using a multirate spring or 3 springs with the spacer each progressively stiffer?
What would the benefit be?.... I think it would simply require more length to accommodate the lower rate springs.... I actually tried that today while looking for springs for my Hatsan, and the weaker spring ends up at coil bind before the heavier spring really does much.... so I didn't bother....
Bob
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I greatly appreciate all the work by Bob and everyone who has added to this thread. I have been following, but haven't had time to test until today. I made a very crude ssg for my wifes .177 marauder. It was getting 50 regulated shots with 10.5gr pellets at 905fps. With my crude ssg and nothing else, it got 90 shots at 909fps. My ES did climb from 16fps to 31fps, but I am sure that I can easily improve the design I used and get the ES back down. It used 1700psi for the 90 shots. Probably not nearly as good as many of you have done, but I am very impressed and thank all of you for the time and dedication in this thread!!
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I greatly appreciate all the work by Bob and everyone who has added to this thread. I have been following, but haven't had time to test until today. I made a very crude ssg for my wifes .177 marauder. It was getting 50 regulated shots with 10.5gr pellets at 905fps. With my crude ssg and nothing else, it got 90 shots at 909fps. My ES did climb from 16fps to 31fps, but I am sure that I can easily improve the design I used and get the ES back down. It used 1700psi for the 90 shots. Probably not nearly as good as many of you have done, but I am very impressed and thank all of you for the time and dedication in this thread!!
AJ 90 shots is still pretty darn good I think! I forgot the formula for efficiency, but that is 1734 total foot lbs total, and I know that is great efficiency. I'm still waiting patiently for when he nails down his Hatsan, so I can play copy cat :D
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You likely have some drag occurring somewhere in the system (possibly the guide in whatever it is sliding through) that is either causing the launch velocity of the hammer to be inconsistent, or on the hammer itself (possibly the spring or guide rubbing inside it), which is causing the inconsistent velocity....
Bob
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I know I'm late to this party, but I have a bit different idea: Why not turn things around? Fix the spring guide in the hammer, and let the mass of the spring and guide be part of its mass. That way, you do not have a loss of hammer energy, and more momentum for a given spring and compression. You would have a spring that departs from the rear end cap for the clearance.
I'm also thinking that you could use a cable type retainer inside the spring instead of a guide to control its extended length. A guide cap on the free end would retain the cable and could be screw adjustable from the access hole in the end cap.
Edit to add a picture for clarity:
Both concepts are in sectional view.
(http://www.ar15.com/media/viewFile.html?i=84279)
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I know I'm late to this party, but I have a bit different idea: Why not turn things around? Fix the spring guide in the hammer, and let the mass of the spring and guide be part of its mass. That way, you do not have a loss of hammer energy, and more momentum for a given spring and compression. You would have a spring that departs from the rear end cap for the clearance.
I'm also thinking that you could use a cable type retainer inside the spring instead of a guide to control its extended length. A guide cap on the free end would retain the cable and could be screw adjustable from the access hole in the end cap.
Thought about this earlier, but I didn't see a cable holding up over repeated shots. It will stretch, and eventually break I'd think. Also, that set up as you describe would require pre-load on the valve, which is the opposite of what the SSG does. It would keep it from over traveling, and may help some, but I don't see a way for it to do what the SSG does. Theoretically, I guess you could do a cable set up that would work similar the SSG, but you would have to de-couple the hammer from the spring. Somebody correct me if I'm wrong here, it wouldn't be the first time :D
*edit
The last part about the cable spring retainer may work, I missed that the first time I read this, because you're talking about two different things.
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Anyone know the thread size of the spring guide on a Marauder (specifically .177 if it matters)?
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I think the idea with the spring guide mounted on the hammer should work, and as I see it there would be no preload on the valve, because the stop on the guide prevents the spring seat from touching the end cap when uncocked.... It is the exact opposite of the idea proposed by Gippeto, where the guide is fixed to the end cap, and hence takes no energy from the spring.... I'm sure as this idea gets bashed about, there will be even more versions of it.... The original one I proposed does not require a different hammer, although you could certainly change it.... Gippeto, and of course this latest one, both require a different hammer.... All will have advantages and disadvantages, and various degrees of simplicity....
Bob
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Anyone know the thread size of the spring guide on a Marauder (specifically .177 if it matters)?
If you are referring to the tension adjustment screw in the end cap, the Gen 1 is 1/2--20. It has a spring guide stub and an Allen wrench hole.
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The original one I proposed does not require a different hammer, although you could certainly change it.... Gippeto, and of course this latest one, both require a different hammer.... All will have advantages and disadvantages, and various degrees of simplicity....
Bob
One could use the original hammer with my concept but with replacing the valve striker (hammer length adjuster) with the guide rod/etc. This would be a rather simple thing to do.
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I played around with the Hatsan today, and got the SSG working in it.... sort of.... First of all, here are the changes to the gun.... First the stock....
(http://i378.photobucket.com/albums/oo221/rsterne/Hatsan%20AT44-10/Stock%20Mod_zpsqhleehq4.jpg) (http://s378.photobucket.com/user/rsterne/media/Hatsan%20AT44-10/Stock%20Mod_zpsqhleehq4.jpg.html)
You can see the recess ground in the top of the stock to miss the stop nut on the SSG.... This is a mirror image of the one in the rear plug, posted earlier.... Now the rear plug, with the SSG in place.... The gun is uncocked, all you can see is the stop nut and the O-ring, against the back of the plastic rear plug.... The guide rod passes through the existing hole in the middle of the plug....
(http://i378.photobucket.com/albums/oo221/rsterne/Hatsan%20AT44-10/Rear%20Plug%20Mod_zpspaz18fmk.jpg) (http://s378.photobucket.com/user/rsterne/media/Hatsan%20AT44-10/Rear%20Plug%20Mod_zpspaz18fmk.jpg.html)
You will notice that I also had to grind a recess in the bottom of the safety button to miss the stop nut, as well as the rear plug.... I don't have a photo of the SSG out of the gun at the moment, but here is a view of the top of the tube and you can see the SSG inside.... The spring sits in it's original seat in the front of the rear plug....
(http://i378.photobucket.com/albums/oo221/rsterne/Hatsan%20AT44-10/SSG%20Inside%20Tube_zps7ub6a4on.jpg) (http://s378.photobucket.com/user/rsterne/media/Hatsan%20AT44-10/SSG%20Inside%20Tube_zps7ub6a4on.jpg.html)
It consists of two 1.75" x 0.045" wire springs on a 3/16" guide, with a preload of 1.2" (almost 14 lbs !).... The cocking force peaks at nearly 19 lbs., but of course the side lever makes easy work of that.... Lastly, here is a photo of the gun reassembled, this is the cleanest possible installation, you can't even see the SSG....
(http://i378.photobucket.com/albums/oo221/rsterne/Hatsan%20AT44-10/Hatsan%20After_zpspkedgeps.jpg) (http://s378.photobucket.com/user/rsterne/media/Hatsan%20AT44-10/Hatsan%20After_zpspkedgeps.jpg.html)
When I saw how much preload was on the original tube, I was concerned that I could come up with an SSG that would be able to launch the hammer hard enough to create the 72 FPE the gun was shooting before.... because the original spring preload of 9 turns (nearly 9 lbs.) would have been supplying a lot of the valve dwell.... Well, as it turns out, I was right.... I have only done one trial (and might actually give up on this SSG conversion), the results were a 21 shot string from 180 bar down to 120 bar, with 25.4 gr. JSB Kings from 952-979-941 fps.... That averaged 52.9 FPE, for a total of 1110 FPE from 14 CI x 60 bar = 840 CI of air total, which works out to 1.32 FPE/CI.... The closest comparable string I have with the original hammer spring setup, was with 5 turns of preload, from 171 bar to 120 bar, 16 shots averaging 52.8 FPE at an efficiency of 1.18 FPE/CI.... Both strings had a 4% ES and the same FPE, so they are roughly equivalent.... This means I have gained 31% more shots, at a 12% increase in efficiency.... However, there is no way with these springs in the SSG I will even come close to 72 FPE....
I have the setscrew in the hammer set right to the bottom, and adjusted the gap to a bare minimum (~ 0.020").... There is so much preload on the hammer spring that when cocked it is within about 1/16" of coil bind.... so there is nothing more available without using a stiffer spring.... At this point, I don't think it's worth it.... I will ponder it for a day or two, but this gun is probably going to return to normal.... The one thing I did accomplish, which I never managed before, was over 2 magazines with the JSB Kings at over 950 fps, so it's a decent setup.... just not the 72 FPE monster I know this gun can be....
Bob
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replacing the valve striker (hammer length adjuster) with the guide rod/etc.
Yes, that would work on an MRod or PRod, but not on a hammer that wasn't drilled and tapped down the middle.... and most of them are hardened which would make that extremely difficult.... Still, it looks like a variation that should work....
Bob
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I wonder if this could just as easily be accomplished by providing the free space for the hammer to travel independent of hammer spring contact but not preloading the hammer spring? Their are several guns like this that do not burp air behind the shot. I think many FX guns are like this. Just a free floating hammer without the complications of pre-compressing the spring and the extra shock of the spring stop.
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I wonder if this could just as easily be accomplished by providing the free space for the hammer to travel independent of hammer spring contact but not preloading the hammer spring? Their are several guns like this that do not burp air behind the shot. I think many FX guns are like this. Just a free floating hammer without the complications of pre-compressing the spring and the extra shock of the spring stop.
I believe Bob mentioned this much earlier in this thread comparing the advantages and effects of the SSG to a shorter, stiffer spring. While similar in some respects, the valve kicking the hammer weight back to the spring still results in some "yo yo" effect as even the stiffer, shorter spring will compress easily at first and send the weight back to the valve wasting some air.
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Anyone know the thread size of the spring guide on a Marauder (specifically .177 if it matters)?
You can also bore the end cap and thread it 9/16-20...this has the potential to allow a 3" spring because there is a fair bit of wasted space lengthwise in the OE( at least in the Gen1 variant ). Going to do this one today, as soon as I can re-borrow that tap that is...:) The spring stop will of course get threaded the same, and since I am turning this bit out of brass it will pose me no issues.
cheers,
Douglas
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Gen II will need a stock modification for the stop to clear.
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Just reread this thread this morning and all I can say is thank you Bob R for choosing to live in the middle of no where. Without the cold Canadian winter you would not have the time to come up with all of your incredible ideas. Usually the math is several steps above my knowledge base but tour mechanical designs are just awesome. Keep on giving me headaches I love it.
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I pulled the SSG out of the Hatsan this morning, and tried changing the springs for the only stiffer choice I had, using two 1.75" long x 0.051" wire springs.... The rifle could not be cocked as the springs went coil bound.... At the moment I'm out of ideas....
Bob
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Anyone know the thread size of the spring guide on a Marauder (specifically .177 if it matters)?
You can also bore the end cap and thread it 9/16-20...this has the potential to allow a 3" spring because there is a fair bit of wasted space lengthwise in the OE( at least in the Gen1 variant ). Going to do this one today, as soon as I can re-borrow that tap that is...:) The spring stop will of course get threaded the same, and since I am turning this bit out of brass it will pose me no issues.
cheers,
Douglas
Douglas,
If you are still in AA I'm only over in Jackson. I'd love to see how yours ends up. I'd like to make a custom back cap but not sure my lack of skills and cheap mini lathe are up to the task. If you end up with any extras through revisions give me a shout.
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Bob, you may want to try a peek valve seat on the AT (~.012" of sealing surface works great against the angled poppet).
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I installed an SSG in my Grouse Gun today.... 2260 PCP Carbine with a 14" barrel and a stock Disco valve and hammer spring.... I used a 2200 spring with 0.90" of preload, which puts it very close to coil bind when cocked....
Previously I got 16 shots with a 2% ES, and 20 shots within 4%, averaging 20 FPE (705 fps with JSB 18.1 gr. heavies), with an efficiency of 1.15 FPE/CI
Now I get 20 shots with a 2% ES and 24 shots with 4%, averaging 21 FPE (722 fps), with an efficiency of 1.50 FPE/CI, an improvement of 30%....
It doesn't seem to matter if the PCP is regulated or not, the SSG can provide big gains in efficiency....
rjorge, that may indeed work on the Hatsan, but would not be a fair test of the SSG....
Bob
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I pulled the SSG out of the Hatsan this morning, and tried changing the springs for the only stiffer choice I had, using two 1.75" long x 0.051" wire springs.... The rifle could not be cocked as the springs went coil bound.... At the moment I'm out of ideas....
Bob
I was afraid it would come to this :( I wish I had more time/tools/parts to try and figure more out. With that being said, I wonder what your setup could do for a lower powered AT-44 at maybe 35fpe in a .22. In my case it would be a no go just for the inability to swap between cylinders and power levels like I currently do, but some one else it could be much better... I wonder what could be done with a cable setup like I_like_irons mentioned too. Either way you've proven it can work. Awesome job just the same Bob!
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Yep, you can install an SSG in a Hatsan AT-44, and get it to work in the 50 FPE range in .25 cal.... higher than that would need other changes, I think....
Bob
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I installed an SSG in my Grouse Gun today.... 2260 PCP Carbine with a 14" barrel and a stock Disco valve and hammer spring.... I used a 2200 spring with 0.90" of preload, which puts it very close to coil bind when cocked....
Previously I got 16 shots with a 2% ES, and 20 shots within 4%, averaging 20 FPE (705 fps with JSB 18.1 gr. heavies), with an efficiency of 1.15 FPE/CI
Now I get 20 shots with a 2% ES and 24 shots with 4%, averaging 21 FPE (722 fps), with an efficiency of 1.50 FPE/CI, an improvement of 30%....
It doesn't seem to matter if the PCP is regulated or not, the SSG can provide big gains in efficiency....
rjorge, that may indeed work on the Hatsan, but would not be a fair test of the SSG....
Bob
From what I have observed, It seems the SSG does not work if you are trying to get max power. Am I right?
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I wouldn't say that at all.... My .25 cal Disco/2260, the 2260 regulated HPA, and 2560 regulated HPA all are tuned with the SSG well up on the knee of the curve, just a whisker below maximum possible velocity at that pressure.... In fact, I found I could tune closer to the plateau velocity and still get good efficiency than I could before I fitted the SSG.... The only gun I haven't been able to get to it's previous power level is the Hatsan.... Three of the guns are tuned about 10 fps faster with the SSG, at much better efficiency than without it....
Bob
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Bob in the case of an at44 if I install an SSG for a short version @30 fpe, will I loose adjustability in spring preload?
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Yep, the guide sits in the middle of the block, so you can't slide the allen key through into the hammer any more.... The preload is set by the length of the guide, and the gap between the end of the guide and the hammer can be adjusted with the setscrew in the hammer, but you have to take the gun apart for every adjustment, the way I did it....
You can't make an SSG cartridge and have it removable, like the others we are using, because the hole through the block is only 7/32", and you can't make it larger or you will hit the trigger assembly.... The spring seat is on the front of the block, and I see no way to change that....
Bob
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Oh... Even though I will lose adjustability, it is probably worth it since I like to have it at 30fpe all the time, based on yours and others results with the SSG I guess 30 shots at 31fpe is possible for a future project.
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I would think that 30 shots at 30 FPE should be no problem.... My stock .22 cal AT-44 Short did 30 shots at 31 FPE (18 gr.) within 7% ES, and 23 shots within 4%.... My best tune was 30 shots at 34 FPE within 4% from 190 bar down to 130.... pre SSG....
Bob
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bob - is your Grouse Gun regulated? and is it a full length 2260 tube?
I am in the process of doing a build like that 2260 14.5 inch .22 cal.
What kind of spring and preload did you use on the final tune?
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Oh... Even though I will lose adjustability, it is probably worth it since I like to have it at 30fpe all the time, based on yours and others results with the SSG I guess 30 shots at 31fpe is possible for a future project.
FYI, I'm getting around 35 shots at 33fpe(JSB 18.1) with my AT-44 long. I have modified the valve/ports and have regulator :) That is a more expensive solution if you don't have a regulator though. The SSG would be far more cost effective.
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Okay Bob, I think I have a plausible solution for the AT-44, but this mod would definitely be more in your ballpark than mine. Prepare yourself for another bad Paint diagram :D I didn't put it in the diagram, but I'm sure it wouldn't be that hard to figure out a way to keep the modified hammer stationary for pre-load adjustment. The part of the hammer that strikes the valve is not attached to the other part. It moves freely after the rear part hits the stop screws. What do you think?
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Actually I have 3 holes plugged mine but the best I can get is 29 shots at 30fpe (18.1) with a 42fps ES, when I said that with the SSG I would like to get 30 shots I meant with a tighter ES...
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match.... My Grouse Gun is unregulated, the reservoir is a bit longer than a 2260 now, I replaced it with a cut-down Disco tube.... It uses a PRod hammer and trigger assembly and a skeleton stock.... Here is a photo when it had the 2260 tube.... If I had the SSG a couple of years ago, I wouldn't have bothered with the slightly bigger reservoir.... It is 2000 psi fill, and 1200 psi refill....
(http://i378.photobucket.com/albums/oo221/rsterne/22%20PCP/2260PCPRepeaterCarbine.jpg) (http://s378.photobucket.com/user/rsterne/media/22%20PCP/2260PCPRepeaterCarbine.jpg.html)
Rallyshark.... so a 2-piece hammer ala Daystate "slingshot", only different?.... *LOL*.... With theirs, the outer part hits the valve and stops and in inner section carries on to open the valve.... Either way, you are losing a lot more energy to the part that stops than with the SSG....
bob
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I wouldn't say that at all.... My .25 cal Disco/2260, the 2260 regulated HPA, and 2560 regulated HPA all are tuned with the SSG well up on the knee of the curve, just a whisker below maximum possible velocity at that pressure.... In fact, I found I could tune closer to the plateau velocity and still get good efficiency than I could before I fitted the SSG.... The only gun I haven't been able to get to it's previous power level is the Hatsan.... Three of the guns are tuned about 10 fps faster with the SSG, at much better efficiency than without it....
Bob
Okay. Thanks! That is good to know!!
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Bob, thankyou thankyou !
I added the SSG to my gen2 .177 Marauder,with a little mod to the stock it fit nicely.
Previously I was running with a regulator at 875fps. for 35 shots and wasting a lot of air from hammer bounce.
This SSG is made with a screw which I polished the rounded head, added a plastic sleeve around the screw. The hard rubber bumper is something a plumber would recognize, it's just a faucet seal I had a few of around in the shop. Lubed inside the hammer and screw head with molly grease.
I set the stock hammer freeplay gap where I thought it should be. This gave 944 fps. with 10.3gr. pellets. Then adjusted the velocity down with the TP adjuster to 877 fps.
I ran a short string of 21 shots over the chrony (I'm real low on pellets) averaged 877 fps. and .6% ES. the report is super short and quiet. Shot cycle is surprisingly smooth. After 56 shots I'm still on the reg. Thats a 3000 fill down to 2200 psi. woohoo ;D and it didn't cost me a dime!
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Bob - for your Grouse Gun did you try a heavier spring or did you stop with the 2200 (what is the spec on that 6# 2.5 inch?)
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I didn't need any more power, so I didn't try a heavier spring.... The 2200 spring is 2.25" long (once set), made from 0.035" wire with 19 coils, and is just under 7 lb/in.... It goes coil bound at 0.70" so has about 1.5" of travel.... and a maximum force of just over 10 lbs.... For the Disco, I would think a 2.5" long version, with a slightly longer rear cap, would give more flexibility for more power.... but you might need a couple thou bigger wire as well, because the rate goes down as you increase the length....
Bob
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Will the SSG work with the WAR no bounce hammer
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Ive been playing with bone stock guns but Im about to try it with the NBH then with the NBH and WAR valve. Results very soon. I predict it will flatten out the shot string and maybe add 1-2 more shots.
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Ive been playing with bone stock guns but Im about to try it with the NBH then with the NBH and WAR valve. Results very soon. I predict it will flatten out the shot string and maybe add 1-2 more shots.
Will it work with your no bounce hammer?
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Ive been playing with bone stock guns but Im about to try it with the NBH then with the NBH and WAR valve. Results very soon. I predict it will flatten out the shot string and maybe add 1-2 more shots.
Will it work with your no bounce hammer?
NBH= No bounce hammer. ;) He is about to try it with the NBH. 8)
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::) ::) OK, I'll take one of each. I had an unexpected bill today. My avatar needed emergency surgery to remove a bunch of bladder stones so no Flex .30 for a few months. Cosmo just cost me $2,000.00 but he is worth it. I figure a few inexpensive mods for the Gen II Marauder will keep me distracted until my mad money is replenished. :)
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I think the idea with the spring guide mounted on the hammer should work, and as I see it there would be no preload on the valve, because the stop on the guide prevents the spring seat from touching the end cap when uncocked.... It is the exact opposite of the idea proposed by Gippeto, where the guide is fixed to the end cap, and hence takes no energy from the spring.... I'm sure as this idea gets bashed about, there will be even more versions of it.... The original one I proposed does not require a different hammer, although you could certainly change it.... Gippeto, and of course this latest one, both require a different hammer.... All will have advantages and disadvantages, and various degrees of simplicity....
Bob
Hmm, the guide fixed to the hammer would be good when more power and higher dwell time is needed. I don't think it actually needs hammer modifications. The spring and guide move at the same speed as the hammer so you could just attach them with epoxy. It might even work with the spring and guide in free-floating mode as they would still participate in valve impact but most likely stop moving once the hammer has bounced back thus even further reducing the mass moving towards the firing valve after bounce.
Edit, on further consideration the mass of the spring that's not moving entirely will slow down the rod and cause it to impact hammer with a short delay. That may create a "blast tamer effect" killing the rebound or just increase the dwell.
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::) ::) OK, I'll take one of each. I had an unexpected bill today. My avatar needed emergency surgery to remove a bunch of bladder stones so no Flex .30 for a few months. Cosmo just cost me $2,000.00 but he is worth it. I figure a few inexpensive mods for the Gen II Marauder will keep me distracted until my mad money is replenished. :)
Speedy recovery pup.
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It is possible the SSG may work with the spring guide completely separate from the hammer and the rear plug.... This would be a method in between Gippeto's and I_like_Irons ideas.... Imagine if you will a spring guide carrying a preloaded spring with nuts on both ends, just sitting between the hammer and the rear cap, with a small gap.... much like a short, stiff spring, but with preload.... For the hammer to rebound and store energy in the spring, it would have to overcome the preload.... The only thing I can see is that you would need a spring with a lot of force, making the gun harder to cock.... and finding enough length could be an issue....
Bob
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Only way I can see it working efficiently is by having the guide being attached to the hammer as described, threaded into the hammer. Then on the backend of the guide there is a hard stop shoulder that have a sliding stop for the spring, so when it is cocked, the hard stop slides through the rear cap, and the sliding stop gets caught by the rear cap compressing it.
Then when it is released the hammer&slide and spring rushes forward towards the valve, the spring gets halted by the sliding stop hitting the shoulder.
The one benefit of this is that there is no ugly nuts or stops on the outside of the rear cap.
(http://i54.photobucket.com/albums/g97/renderbrandt/SSG%20Hammer.png)
The potential problem is that the shoulder would get caught/rub on the rear cap when released. Which could be fixed by making the sliding spring stop almost full sized (hammer OD) and act as a centering device for the guide.
(http://i54.photobucket.com/albums/g97/renderbrandt/SSG%20Hammer2.png)
(http://i54.photobucket.com/albums/g97/renderbrandt/SSG%20Hammer2B.png)
Infact that would work just great I think, as the sliding stop will be pushed against the rear cap until the "gap" is reached and the shoulder meets up with it.
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I've been busy doing some drawing, and I have a Gen 1 Marauder SSG (inverted) designed. If someone would be so kind and check the dimensioned drawing---these do not have tolerances, yet.
The thing I've designed is adjustable for hammer energy. It does not affect the maximum cocking force, for that is essentially fixed. However the hammer stroke is quite adjustable.
The first drawing shows four states of the system. Note, the back of the spring guide stays pretty much at the rear support in the end cap.
(http://www.ar15.com/media/viewFile.html?i=84347)
By shortening the hammer stroke you reduce the hammer energy. Consider that the Work (Energy) in the spring is product of the average force and the length. By shortening the stroke you do two things. First the length is shorter. Second the average force goes up.
Consider a 10 pound/inch spring that has an average force of 10 pounds on a 1" stroke. The pre-load is 5 pounds, the final load is 15 pounds. This is an energy of 10 in-lbs.
Now let's take my system and reduce the stroke length to a half inch. The pre-load now goes up to 10 pounds while the final load stays at 15. The average force is now (10 lbs + 15 lbs) / 2 = 12.5 lbs. The stroke is now 1/2". The equation now is 12.5 lbs x 0.5 in = 6.25 in-lbs.
--------------------------------------------------------------------------------------------
The heart of the system is the Striker Rod. It's length is fixed and is supposed to have a little bit of clearance between the end cap stop and face of the valve pin. This clearance can be adjusted a bit with shims if needed.
(http://www.ar15.com/media/viewFile.html?i=84348)
The last few parts are in this last drawing. The e-clip is a standard item. Note: the washer should have a press fit on the end of the Striker Rod to help transfer force and keep from relying solely on the e-clip.
(http://www.ar15.com/media/viewFile.html?i=84349)
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Let me understand this correctly, the striker rod would require enough relief inside the hammer to allow the tip of the striker to be buried inside without touching the hammer at it's resting position? What is moving the hammer upon release, the front spring guide?
That sounds like a lot of very minute clearance "catch you's"
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On quick review, your math looks correct.... My comment would be that I have never understood why anyone would want to shorten the hammer stroke unless they are severely detuning an MRod to work at much lower pressures than can be accomplished by reducing the preload alone.... I have never understood why anyone would choose higher cocking force over longer stroke, but that is what some like to do.... You are correct that by cutting the stroke in half, in your example, you can reduce the hammer energy, but with still 15 lbs. of cocking force, I wonder why you would do that?.... To each his own, I guess.... I use PRod hammers in many of my builds, and the first thing I do is remove the flanged striker, and replace it with a 1/4"-28 setscrew with the end ground flat, and recessed between 1/16"-1/8" in the face of the hammer to increase the stroke.... but I think that your system would work as you say, providing you have the appropriate spring to achieve the energy you need in the space you have availabie with the travel you have adjusted to....
To clarify my post above about the "loose" guide just imagine Gippeto's arrangement, but with the back end of the guide carrying a preload adjusting nut, and butting up against the gap adjusting bolt.... When uncocked, the hammer and guide assembly both rattle around loose, with a slight total gap.... When cocked, the sliding collar on the guide pushes against the back of the hammer, forcing the end of the guide back and then compressing the spring.... The front of the guide slides down inside the hammer (actually the hammer slides back around it).... Sufficient depth inside the hammer is required to allow for the hammer stroke.... In this case, the guide remains still, and only the hammer is accelerated, as in Gippeto's design....
Alternately, you could turn the thing around, and have the stop collar hit the gap adjusting bolt at the back, which is drilled to allow the end of the guide to pass through it and possibly project a short distance behind the head of the bolt when cocked.... Part of the spring length lives inside the hammer.... In this case, the mass of the guide is propelled along with the hammer, just like a free-floating guide captured by the spring works.... and aids in opening the valve, as in I_like_Irons design.... In both cases, there should be no alignment problem with the guide, which can occur when you mount the guide solidly in either the hammer or rear cap.... I can tell you from experience with rear-cockers that if the guide is not perfectly aligned with the hammer, it will hang up in the RVA adjuster it slides through.... In I_like_Irons design, a misalignment of the back end of the guide with the rear cap could cause the hammer to bind, for example....
So, there are a ton of different ways to get to the same result.... Some will work better than others, in certain situations or in certain guns, while others may not be feasible or desireable in those same guns.... I'm just glad to have started the ball rolling so that we can take advantage of using preload in the hammer spring, with a gap between the hammer and valve stem, to eliminate air-wasting hammer bounce....
Bob
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If you can deal with 1/4" O.D. McMaster Carr has aluminum standoffs of various lengths to make a neat looking package.
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Just finished up an SSG devise for the BSA Scorpion .... same design as M-rods previously.
Utilized a longer 6# spring with heavy preload. Power easily adjusted to get the JSB 8.4's at 900 fps.
Stupid quiet operation with most noise from hammer spring vibration / strumming. Need to engineer a fix for that cause it is annoying !
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My comment would be that I have never understood why anyone would want to shorten the hammer stroke unless they are severely detuning an MRod to work at much lower pressures than can be accomplished by reducing the preload alone.... I have never understood why anyone would choose higher cocking force over longer stroke, but that is what some like to do.... You are correct that by cutting the stroke in half, in your example, you can reduce the hammer energy, but with still 15 lbs. of cocking force, I wonder why you would do that?....
To answer your first question, I tune my Marauder and Armada to work with fairly low pressure (150 Bar and 160 Bar respectively). I do not have facilities to get an SCBA bottle filled anywhere locally. The lower pressure allows me to get quite a few fills with a SCUBA tank. Also, the effort to fill with a hand pump is easier as well.
My desires are not for maximum projectile energies---far from it. I desire a greater shot count for a fill, along with keeping my pellet velocities at or slightly below Mach 0.8. In the case of the Armada, I'm trying to duplicate the wind drift (in terms of MOA) at 50 yard with what I get with my highpower competition space-gun at 600 yards. This .25 rifle does that at about 760 ft/s.
The example was with the stock spring and the approximate dimensions. It was purely and example to demonstrate how the change in hammer stroke affects its energy. I is not necessarily what one would want to do, however.
The design is intended to be a drop-in and allow one to use any spring that works with an un-modified Gen 1 Marauder, and to allow for additional adjustment as well.
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If you cannot tune to 150-160 bar with just preload and spring changes, then I can understand reducing the hammer stroke.... I did not mean to offend in any way, there is no right or wrong way to do the SSG.... and I'm glad you got involved and came up with another iteration of the concept that does what you need it to do....
Scott, it's interesting you are now hearing things you could not hear before because of the air not being blown out of the muzzle after Elvis has left the building, isn't it....
Bob
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I have been watching and waiting, hoping that a consensus would be reached on the BEST implementation of the SSG concept.
I can see that that isn't going to happen. :P
What is very exciting is that the concept is so adaptable for applications all the way from max shot count light duty stuff, all the way to high power big bore. ;) The cooperation and exchange of ideas in this thread is a pleasure to watch. ;D
Lloyd-ss
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Yep, Lloyd, pretty much take your pick, there are at least 6 ways to do it now, from what I can see.... *LOL*.... Some need more room than others, ones with more length available can have lighter cocking forces.... Choose one that you think suits your application and have at it....
Bob
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Got to the materials store; some AL for the guide/indicator and on a whim, some plastic for the end cap nut( Acetron ) from their drops box. At 4" long the guide rod is 5.2 grams running a diameter suitable for 10-32 threading. As soon as I get the nut done, I will cut to length and thread. Springs are dual 1.5" in .059 and .055 wire. The .059 will yield me a combined spring rate of nearly 18 lb/in, and the .055 a rate of 14 lb/in. I dropped the diameter from the OE .480" to .420".
The big valve in the .224 Marauder looks to be *VERY* close to bounce under normal conditions. With the heavy spring now in it, I lubed the tube well with moly grease, and followed with some dry powder. On another gun with a comparable valve I did the same, and after a round of testing I wiped most of the heavier goo out and found it wasted air like a fiend due to bounce. Re-installing the moly goo stopped it to a great extent. I am looking forward to both increasing the power( last max was 103 fpe at 2700 psi ), and gaining some efficiency...as well as some added consistency from lowering hammer drag.
cheers,
Douglas
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Made a initial run on a bone stock .22 but had about 8 no reads I erased so shot count is a little low. http://airgunguild.com/index.php/topic,11.0.html (http://airgunguild.com/index.php/topic,11.0.html)
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Rallyshark.... so a 2-piece hammer ala Daystate "slingshot", only different?.... *LOL*.... With theirs, the outer part hits the valve and stops and in inner section carries on to open the valve.... Either way, you are losing a lot more energy to the part that stops than with the SSG....
bob
I'm not at all familiar with the Daystate setup, since I'm a newb and have very little experience with anything other than my AT-44. I think that sounds kinda neat though. I wonder how the Daystate would work with the inner section made of tungsten, and the outer of a "lighter" metal? All of my ideas are pretty much out of me noggin. I know it would be losing energy, but I was just trying to think of a way to do it and still be able to adjust it, without disassembling the gun. Maybe, with some materials change, the energy loss could be lessened, but I get what you're saying for sure. It's not fair that everybody else gets to have an SSG, and I don't,lol!
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For the tune you have in your AT-44 you can probably get the SSG to work just fine.... It just wasn't up to the 72 FPE I'm after I mine....
Bob
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If I didn't have two separate air cylinders that are meant for different purposes, I'd be all over it. I don't see the feasibility of taking the gun apart to adjust it for one cylinder or the other. I don't think the same settings would work between the two cylinders very well, and I'd just end up compromising on one or the other. That is why I've been trying (unsuccessfully) to come up with an SSG like solution that is still adjustable without dis-assembly. The only way I can think to make the SSG work for both cylinders would be to set it for the high power cylinder, and turn my reg down and hope for the best with my other cylinder? I'm certainly open to suggestions, if I'm wrong on this though :)
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Scott, it's interesting you are now hearing things you could not hear before because of the air not being blown out of the muzzle after Elvis has left the building, isn't it....
Bob
Lol ... been that way a couple years now as operational racket and blast gets tamed. Whats most impressive with the SSG device is that bounce is now so negated you can hear hammer making valve strike, valves air pulse within the action.
Pay attention to what those noises origins are perhaps correcting a minor air leak as transfer port, maybe a striker pip to quiet valve strike & you get a PCP to really be quite stealth ;)
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Scott I found a very simple way of getting rid of the spring Twang without messing with the tune. I put a 80D urethane oring between the spring and adjustment body it works like a charm my friend, same thing i do with NBH and spring.
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Method #7 potentially http://airgunguild.com/index.php/topic,11.msg140.html#msg140 (http://airgunguild.com/index.php/topic,11.msg140.html#msg140)
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Just finished up an SSG devise for the BSA Scorpion .... same design as M-rods previously.
Utilized a longer 6# spring with heavy preload. Power easily adjusted to get the JSB 8.4's at 900 fps.
Stupid quiet operation with most noise from hammer spring vibration / strumming. Need to engineer a fix for that cause it is annoying !
Hey, some photos or it didn't happen. I've been considering a SSG for my BR Scorpion so it would be nice to see how you did it. Do you reckon it would be enough to push pellets at 55+ fpe in .25 caliber Scorpion?
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Just finished up an SSG devise for the BSA Scorpion .... same design as M-rods previously.
Utilized a longer 6# spring with heavy preload. Power easily adjusted to get the JSB 8.4's at 900 fps.
Stupid quiet operation with most noise from hammer spring vibration / strumming. Need to engineer a fix for that cause it is annoying !
Hey, some photos or it didn't happen. I've been considering a SSG for my BR Scorpion so it would be nice to see how you did it. Do you reckon it would be enough to push pellets at 55+ fpe in .25 caliber Scorpion?
Same deal as previous ....
Machined a HAT just a bit smaller than diameter of hammer cavity, small shoulder to center spring having a short shank threaded for screw.
OEM marauder 6# hammer spring. Made a delrin spring guide that rests in rear cap to counter spring cant & kill buzz. * It fitting spring I.D. and at a length just shorter than compressed length required when cocking gun. Head of screw resting on adjuster dust cap w/ o-ring.
Did try it with hat against hammer core, then again keeping the Red rubber buffer in place between Hat and hammer finding operation quieter with it being there. Running a gap of @ .040" or so.
Cut a clearance slot in stock and were done.
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Just finished up an SSG devise for the BSA Scorpion .... same design as M-rods previously.
Utilized a longer 6# spring with heavy preload. Power easily adjusted to get the JSB 8.4's at 900 fps.
Stupid quiet operation with most noise from hammer spring vibration / strumming. Need to engineer a fix for that cause it is annoying !
Hey, some photos or it didn't happen. I've been considering a SSG for my BR Scorpion so it would be nice to see how you did it. Do you reckon it would be enough to push pellets at 55+ fpe in .25 caliber Scorpion?
Same deal as previous ....
Machined a HAT just a bit smaller than diameter of hammer cavity, small shoulder to center spring having a short shank threaded for screw.
OEM marauder 6# hammer spring. Made a delrin spring guide that rests in rear cap to counter spring cant & kill buzz. * It fitting spring I.D. and at a length just shorter than compressed length required when cocking gun. Head of screw resting on adjuster dust cap w/ o-ring.
Did try it with hat against hammer core, then again keeping the Red rubber buffer in place between Hat and hammer finding operation quieter with it being there. Running a gap of @ .040" or so.
Cut a clearance slot in stock and were done.
Did you notice any improvements in shot-to-shot consistency?
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I decided to give this a try on the cheap. All I have invested is a 1/4"x2 1/2"x20 bolt, a nyloc nut, a plastic washer, an oring for an oring kit and a shorter spring. I'm looking for mild/modest power out of my .177 Gen 1 Marauder but with efficiency. I have a tube extension so I'm guessing I'm somewhere around 285cc of volume or 17.4 ci.
First run was with the factory spring, just tightened one full turn of the 20tpi nut from touching the hammer (roughly 0.05" gap). CPHP were shooting 1150 from a 2800psi fill. First time I've heard a pellet go super sonic in the basement. I wasn't looking to push those pellets that hard so I swapped a spring from Menards in place.
Second try resulted in 80-85 shots within 4% of the 1001FPS max I saw (didn't write them all down, just took an average of three every 10 shots to keep things moving) from 2200psi to 1525psi peaking at 2000psi-1800psi with 30-35 shots holding under 2% ES.
I've got a few more springs to try out. I don't dislike the power but I'd like some heavier pellets to drop velocity a bit. I have a feeling these are still moving a little too hot. I have the striker all the way in to the hammer so that could be extended to cut velocity a little. The preload is about as minimal as this spring will take to get off the hammer. What I can see is I'm somewhere around 1.65-1.70 fpe/ci and its at a point that is very SCUBA tank friendly. I may try a slightly shorter/softer spring but cocking effort is very manageable so maybe the striker is a better adjustment at this point.
I no longer hear the hammer bouncing off the valve. I tried the Bstaley mod but still thought it sounded like it was bouncing a bit. This is as dead as it gets after the initial opening of the valve. Not pretty how she sits but I'm happy with how efficient she has become.
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Just finished up an SSG devise for the BSA Scorpion .... same design as M-rods previously.
Utilized a longer 6# spring with heavy preload. Power easily adjusted to get the JSB 8.4's at 900 fps.
Stupid quiet operation with most noise from hammer spring vibration / strumming. Need to engineer a fix for that cause it is annoying !
Hey, some photos or it didn't happen. I've been considering a SSG for my BR Scorpion so it would be nice to see how you did it. Do you reckon it would be enough to push pellets at 55+ fpe in .25 caliber Scorpion?
Same deal as previous ....
Machined a HAT just a bit smaller than diameter of hammer cavity, small shoulder to center spring having a short shank threaded for screw.
OEM marauder 6# hammer spring. Made a delrin spring guide that rests in rear cap to counter spring cant & kill buzz. * It fitting spring I.D. and at a length just shorter than compressed length required when cocking gun. Head of screw resting on adjuster dust cap w/ o-ring.
Did try it with hat against hammer core, then again keeping the Red rubber buffer in place between Hat and hammer finding operation quieter with it being there. Running a gap of @ .040" or so.
Cut a clearance slot in stock and were done.
Did you notice any improvements in shot-to-shot consistency?
I did ... rifle had a self done blast tamer in place. Rifle shot well enough but was still using more air than i thought it should.
BT removed and SSG in place the SOUND of shot now much less telling me valves getting closed much faster ( Reduced dwell )
The ES figures are comparable or a tad better. Efficiency of air use appears to be the greatest attribute.
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Method #7 potentially
Isn't that just the original with different materials?.... I meant 6 different modes of operation, as to fixed guide, guide on hammer, floating guides in both directions, etc.etc....
Bob
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I agree just different ways to skin the same cat. #7 though prevents almost all the rod from extending out the rear of the gun.
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#7 though prevents almost all the rod from extending out the rear of the gun
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HUH?.... Looks like the end of the guide and stop nut you can see in the photo, and it's uncocked.... How does it do that?....
Bob
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Yea bad picture(drawing) Ill cad something up so it makes more since. But basically the plunger on the hammer slides in and out a orifice on the hammer, the other end is just like before just shorter.
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So the washer on the front of the guide (against the nut) hits the back of the hammer (like in Gippeto's idea) and the guide and nut slide down into the center hole of the hammer?....
Bob
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All I can say is wow.
Lots of you guys are getting excellent results. It's taking me more time than I wanted but, I am almost there for testing. I need to find a sleeve for the guide. The system is a little too "crunchy" still.
I went with Travis direction a little with the cassette style.Drilled and taped the end plug all the way for 1/2 X 20 so I can remove the entire SSG without taking the gun apart. This also allows for a longer spring. it's nice but just not smooth yet to try out. I also do not like the guide sticking out so I may counter sink it into the knurled part of the preload adjuster.
I am really curious to know if it will out perform the short stiff spring. I saved an old doc file from testing with the dual wire spring at 1.8" long and 20lbs/inch. According to Travis's .22 numbers at 24 fpe the short stiff spring got a little more at 70 shots under 5% last year.
After reading so much I am starting to wonder if it's not the "bounce" and it's the "preload" that is causing the extra dwell. Since the SSG and the short stiff spring do not use preload it appears as it is starting to boil down to at what is the lowest pressure you can run without a bounce that causes a re-opening of the valve.
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Hi All, newbie here. I finally figured out what was the cause of some pretty extreme sudden hammer bounce (http://www.gatewaytoairguns.org/GTA/index.php?topic=99581.msg967630#msg967630) I have been experiencing, but the experience had me rethinking the idea of a hammer debounce device. Somewhere along the way, I found this thread. Awesome idea, and I would like to implement it and see what more efficiency I might gain ... I am wondering, can this all be done with hardware store parts and a drill press? I don't have nearly the experience many of you have, and while I can get access to a lathe, it is about an hour and a half from home. I have a small tap and die set...
Currently, I have a 2400kt that has been converted to air, with a challenger RVA installed at the back. It seems to me that I can get one of those long bolts that is only threaded at the end to act as the spring guide, another to act as the adjusting knob, and I can use the original end cap from the gun. Does this sound right? Since I am seeing that this works best with a longer, weaker spring, would the original hammer spring from the gun suffice? Likely I am oversimplifying things.
This is for a 24" barrelled 2400kt in .177 that has been converted to HPA. It has an unmodified disco valve and spring and is currently at 1200psi. I am gonna see what I can get with lower pressure, but it is currently launching 10.3 grain jsb heavies at about 910fps, well into the knee of the curve, as Bob puts it...
... so can this be done with my caveman tools?
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Hi All, newbie here. I finally figured out what was the cause of some pretty extreme sudden hammer bounce (http://www.gatewaytoairguns.org/GTA/index.php?topic=99581.msg967630#msg967630) I have been experiencing, but the experience had me rethinking the idea of a hammer debounce device. Somewhere along the way, I found this thread. Awesome idea, and I would like to implement it and see what more efficiency I might gain ...
... so can this be done with my caveman tools?
Just read the thread and pick up on the earlier thoughts shared on WEIGHT that hammer spring must move tho have no effect on actual strike energy, and the need for enough strength of the stop rod being able to tolerate repeated impacts of decelerating the stop rod components. ( Think small jack hammer ) and build accordingly.
Have fun !!
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I guess I have a dumb question, but why couldn't you just put say a 15/16 od by about an inch long medium light spring in front of the hammer kinda like a bstayley mod or the gen 2 NBH with the small spring and pointer Travis had. The spring shall be light enough to touch the hammer and valve at the same time lightly holding the hammer back until fired and push the hammer back instantly. only adjustment would be the striker. Just crazy thinking.
Bob
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The spring as you describe, aided by the closing of the valve, would throw the hammer back even harder, to store even more energy in the hammer spring.... Whether or not it could prevent a re-strike would be a matter of getting the rates perfect.... The stronger you have to make the return spring to prevent the hammer re-opening the valve.... the harder you would have to launch the hammer on the firing stroke to get the dwell you need.... It may or may not work as intended.... but for sure you will need more hammer energy, making the gun harder to cock....
Bob
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bnowlin I didnt put the adjustable spring poppit in front of the NBH to prevent bounce thats what the shoe on the hammer does I put it there to prevent over dwelling the valve at lower pressures thus extending the shot curve and not creating burping at lower pressures. It worked fantastic but trying to explain to customers how to set the curve and dwell and poppit distance was overwhelming so I deleted it unfortunatly.
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Yall make my head hurt anyway, but it was just a thought LOL. Bob makes a lot of sense. Like the TV commercial "Grandpa how do you know so much"? I still like all your mods Travis. BTW Bob thanks for explaining. You to young-en.
Bob
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I'm ordering a couple of parts for my Disco this am.
Your idea is very, very simple to do and sounds like it makes a huge difference in the guns dynamics (more shots, quieter, more consistency) What i like is all parts are at your local hardwars store and more heavy duty machining or expensive equipment is required to do it !
I'm very much looking forward to trying this ... does this in effect do away with the RVA ?
wll
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Bob,
Using a stock Disco hammer spring and clipping a couple of coils off and then doing your SSG, would that soften up the spring a bit where someone would not need to go and buy or find another lighter spring ? Just curious !
Also, it looks like this modification will not work on the QB series of guns ... gosh darn !
wll
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If you did the reversed cocking mod, cock on open, it might allow for an SSG, no? Of course that could be nonsense, only guessing, as I've not done that change on mine. I actually like the stock setup for the bolt, and have resolved hammer bounce with an O-ring buffer ahead of the hammer combined with a little steel friction denouncer, so won't worry about an SSG for my QB78.
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wll.... clipping coils off a spring actually INCREASES the spring rate (makes the spring stiffer).... but it reduces the preload in a given amount of space (which is why it detunes a non-adjustable gun).... You want the opposite effect to use an SSG to the best advantage, a longer, softer spring with lots of preload....
I did a QB earlier in this thread, but it was cock-on-open....
Bob
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First FAILURE to get a working or more efficient SSG :-\ .... Not for reasons of the actual devise, but one where no gain was found using it.
BAM 50 regulated conversion gun where rifle was set up using a quite light 30 gram hammer, relatively long @ 15# spring. Rifle was launching 25.4's @ 900 fps while giving near 1.40 efficiency numbers.
Made up my typical design SSG and no mater how much spring energy added could not get the power back.
* Obviously a hammer weight issue, So ... tossed in a modified factory hammer of @ 90 grams and tried again.
Yea it worked and made the power, but air use was no better and gun got louder too :P Longer dwell from the greater hammer weight. More noise = more air use, so we actually went backwards.
So took the set up back to where it was and calling it good as it was.
Have no doubt this particular rifle as set up could be balanced with some hammer weight in-between the 30/90 gram weights played with.
* Whats interesting and being a first where a REALLY LIGHT HAMMER set up conventionally worked better than the HEAVY factory hammer and an SSG devise. It leaves me to ponder that hammer weight still plays a role here in controlling dwell independent of hammer bounce issues we have been focused on :o
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If you aren't getting any hammer bounce that is wasting air with a given tune, then the SSG cannot improve on the situation.... That seems obvious, and is proof that you had already done your homework.... I had a failure in getting back to where I was for power in my Hatsan, likely due to the room available because of the rear block, and the fact I could not move the rear spring seat further back because of the trigger assembly being in the way.... I think we have to accept the fact that some guns just will not benefit from the SSG (unless some other creative work-around is found).... while others benefit greatly....
Bob
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The last 2 posts (motorhead and Bobs) is very interesting to me.
For me, using a short stiff spring I can get a great efficiency. For Scott, the light weight hammer gets his great efficiency.And Bob mentioning that if the system is already efficient the SSG may not improve it.
What's going through my head now is, how efficient can we make our guns.
Is there a calculation (or example) that tells us what the max efficiency can possibly be with lift and dwell. I already know and proved on my gun that fps was not only dependent of lift but dwell affected fps just the same by using a steel stop for lift control.
I would like to leave bounce out because bounce mostly occurs at very low pressures .
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I think Electronics will control the future of ultra efficient air rifles but then what do I know after reading some of Bobs post my brain was scrambled. lol
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At the bottom of Lloyd Sikes' PCP efficiency calculator page he's got a chart indicating roughly the potential efficiencies for Low, Moderate, High, and Maximum Power PCPs. In that order he lists ranges of 1.4 to 2.0, 1.0 to 1.4, 0.7 to 1.0, and 0.7 or less. So it seems he's saying maximum efficiency is directly tied to output power, with more power equating to lower efficiency. In the low power range one example is my Pardini K12, from which I get over 100 shots per fill though it's just a tiny air pistol cylinder, averaging a bit under 5fpe. I don't know the internal volume of the cylinder so can't calculate efficiency, but there's really not a lot of waste going on. If I crank up the hammer spring I can get up to about 7.5fpe max, but it's loud and the shot count drops to half.
The best efficiency I've managed with an airgun is about 1.65FPE/CI, using a short, moderately firm spring on an RVA and a lightened striker, this on a relatively low-ish power Crosman carbine. Adding an SSG and playing with various spring strengths and lengths has so far netted me shorter strings and poorer efficiency. No doubt I'm doing something wrong, but on the other hand the simpler RVA setup with the short spring was a very thoroughly worked out tune, something I spent a lot of time refining.
On a different Crosman, a 2260 to which I added an SSG last night and finished adjusting this morning, I've been able to take it from 1.32FPE/CI with a similar shorter spring and RVA with lightened hammer up to 1.53FPE/CI at about 18.8fpe, using moderately strong springs with a lot of preload. Shot count increased with the 2260. I expect some different spring gauges will help in fine-tuning the first airgun so as to bring me back up to a higher shot count and efficiency in that lower powered setup.
If you're after raw power from a big bore I think just dumping as much as you can into the pellet/bullet is going to net the desired result, but if you can manage to live with dialing the power back 20% or a bit more an SSG will probably be useful in increasing shot count and consistency. Specific numbers... I have no idea, and I'm unlikely to do anything with anything larger than .22" anyway, just don't have the need. Same for power levels as more than about 20fpe is more power than I'll ever want for airgunning. In some of Bob's older posts in castboolits and other places he indicated that dialing back in velocity a bit enabled increases in power for moderately high-powered applications something like jumps from 1.05FPE/CI to 1.20FPE/CI. The SSG might well shift both those numbers upwards on some rifles.
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On a different Crosman, a 2260 to which I added an SSG last night and finished adjusting this morning, I've been able to take it from 1.32FPE/CI with a similar shorter spring and RVA with lightened hammer up to 1.53FPE/CI at about 18.8fpe, using moderately strong springs with a lot of preload.
Gerard,
Could you tell us the volume of your 2260 reservoir and the number of shots at 18.8 fpe you are getting after installing the SSG? I am going to try the SSG on my Prod and some pics or details of your setup would be very helpful, if possible.
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Sure. It's actually averaging 18.88fpe over 21 shots using 14.39gr JSB Express pellets. Volume of the 2260 reservoir after subtracting the long front fill plug (foster type, metal filter at inner end, two O-rings) and the aluminum gauge block, is 65cc remaining ahead of the modified Disco valve. Pressure dropping from 1500psi to 600psi. My results with the SSG were all over the place, initially giving only five reasonably consistent shots from 1,000psi. I could attain as higj a figure as 896fps with no SSG gap. More pressure was provong difficult as velocity was often dipping below 500fps. A lot of trial and error sorted things out. The correct settings had it climbing to 21 shots. There is now about 0.03" gap. Initial preloaded spring 'weight' is about 6lbs. Bolt draw climbs to around 18bs at the instant before the sear catches. I might be able to use longer springs with thinner wire with a longer guide rod and rear cap,... but I like the steel cap I have and don't mind the hard bolt handle pull. Softer springs with this guide rod length just didn't work at all. Velocities were between 200 and 450fps with the longest 0.8mm wire spring I could cram in without coil bind preventing cocking.
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Thanks Gerard! That should save me some time and pellets...
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Yeah... pellets... dangit. Must have put 700 of those little JSB jewels over the F1 in the past week trying to wrestle two SSGs into shape. But it's for a good cause if we all share. Just wish JSB pellets weren't fast approaching .22lr in cost!
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Here are all the major variations of the SSG that have been invented so far.... They all share two common traits.... there is preload in the spring, but the spring does not push on the hammer at rest when uncocked.... These two features combine to prevent hammer bounce.... The concept first discussed was to use a Gas Ram to achieve this, but unavailablitly of a suitable unit caused me to simulate the way it worked by using a spring on a guide with a stop to create the preload and a gap to the hammer.... Here are the various configurations suggested to date, some tried and some not.... All these drawings share the same features and were drawn to the same scale, although they may have changed slightly by the time they got uploaded....
1. They have the preloaded spring 10 units long. Spring and guide is shown in black.
2. They have a hammer stroke of 7 units, with enough room for that to occur everywhere.
3. They have an adjuster (shown in red) for the gap between the hammer guide and hammer, which also changes the distance the spring compresses when cocked.
4. The green feature is the end cap, all end caps and gap adjusters are drawn the same size.
5. The hammer is shown in purple, and is longer for the ones that require a deep hole in it.
6. If a sliding collar is required on the guide, it is shown in blue.
(http://i378.photobucket.com/albums/oo221/rsterne/Parts%20for%20Sale/SSG%20Gas%20Ram_zpshzvard5u.jpg) (http://s378.photobucket.com/user/rsterne/media/Parts%20for%20Sale/SSG%20Gas%20Ram_zpshzvard5u.jpg.html)
Gas Ram suggested by stalwart
(http://i378.photobucket.com/albums/oo221/rsterne/Parts%20for%20Sale/SSG%20Original_zpsc7o9n5b6.jpg) (http://s378.photobucket.com/user/rsterne/media/Parts%20for%20Sale/SSG%20Original_zpsc7o9n5b6.jpg.html)
SSG suggested by rsterne
(http://i378.photobucket.com/albums/oo221/rsterne/Parts%20for%20Sale/SSG%20Through%20Hammer_zpsucpfddqr.jpg) (http://s378.photobucket.com/user/rsterne/media/Parts%20for%20Sale/SSG%20Through%20Hammer_zpsucpfddqr.jpg.html)
Above suggested by bstaley.
(http://i378.photobucket.com/albums/oo221/rsterne/Parts%20for%20Sale/SSG%20Fixed%20at%20Rear_zpsn0bgtpm0.jpg) (http://s378.photobucket.com/user/rsterne/media/Parts%20for%20Sale/SSG%20Fixed%20at%20Rear_zpsn0bgtpm0.jpg.html)
Above suggested by Gippeto.
(http://i378.photobucket.com/albums/oo221/rsterne/Parts%20for%20Sale/SSG%20Fixed%20in%20Hammer_zpsimygf31t.jpg) (http://s378.photobucket.com/user/rsterne/media/Parts%20for%20Sale/SSG%20Fixed%20in%20Hammer_zpsimygf31t.jpg.html)
Above suggested by I_like_Irons
(http://i378.photobucket.com/albums/oo221/rsterne/Parts%20for%20Sale/SSG%20Loose%20Guide%20Stationary_zpszp4xodm4.jpg) (http://s378.photobucket.com/user/rsterne/media/Parts%20for%20Sale/SSG%20Loose%20Guide%20Stationary_zpszp4xodm4.jpg.html)
Above suggested by rsterne
(http://i378.photobucket.com/albums/oo221/rsterne/Parts%20for%20Sale/SSG%20Loose%20Guide%20with%20Hammer_zps3tmneipu.jpg) (http://s378.photobucket.com/user/rsterne/media/Parts%20for%20Sale/SSG%20Loose%20Guide%20with%20Hammer_zps3tmneipu.jpg.html)
Above suggested by rsterne
It is not the intention here to show every possible variation of materials or construction, but only the major differences in operating methods.... In my original design, the spring is captive in the rear gap adjusting nut, is accelerated by the spring and comes to a halt just before the hammer hits the valve, wasting the energy used to accelerate it.... After my original design, which several people have tried, two variations were proposed in which the guide was fixed at one end.... In Gippeto's version, it was fixed at the back, adjustably, into the gap adjuster in the end cap.... The guide does not move, the spring does its work pushing against a sliding collar which then pushes on the hammer.... The collar stops just before the hammer hits the valve.... No energy is used in accelerating he guide, only the small collar.... but the weight of the guide does not assist the hammer strike.... In a version proposed by I_like_Irons, the guide is fixed in the hammer and travels with it, but maintains preload adjustability where it threads into the hammer.... It also uses a sliding collar on the guide, but at the back, pushing on the gap adjusting nut.... The weight of the guide takes energy to accelerate, but that energy becomes part of the hammer strike....
The two remaining versions I have proposed, to take advantage of the above ideas, but without requiring the guide to be fixed to either part, it remains free-floating, with a gap to the hammer adjustable by the red adjuster.... Both versions require the sliding collar.... In the first version, the guide remains stationary and the collar slides, like in Gippeto's, requiring no energy to accelerate it, but does not contribute any to the hammer strike.... In the second version, the guide travels with the hammer, while the collar stays still, like in I_like_Irons version.... which requires energy to accelerate the guide, but it gives that energy back as part of the hammer strike....
The versions where the guide stays still at the back don't stick out the back of the gun, but require room inside the hammer to accommodate the guide during the cocking stroke, so the hammer has to be deeper than the stroke.... The versions where the guide move with the hammer don't stick out the back as far as my original version, but require that the back end of the guide, including the diameter of the stop nut, be able to clear the inside of the gap adjuster without interference or hanging up.... Each version will have it's own limitations, advantages and disadvantages.... Some will be suitable in some guns and not others, and vice versa....I hope by showing all the versions in one place that might help clarify their similarities and differences....
I apologize for not including bstaley's suggestion, I have now added it, in the order it was suggested.... I simply missed it when doing this compilation.... It uses the guide rod passing through the hammer, with a gap between it and the valve stem.... The hammer must be shortened by the thickness of the stop on the front of the guide.... The gap adjuster still works the same, but against the end of the shaft, and the preload can be set by moving the stop nut on the guide.... The guide is stationary until struck by the hammer, which then must accelerate the mass of it and the spring before striking the valve.... Otherwise, it has all the same features as the others....
Bob
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Bob,
Very nice consolidation of design ideas.
Sadly few PCP guns have sufficient distance or length from hammer to rear retention cap to utilize many of these designs.
Personally having quite a few PCP's and working on more, ORIGINAL design first proposed appears in my estimation to be the most applicable to the PCP guns many would find them self's modifing for SSG fitment.
Unless something monumental in our collective think tank is being over looked, see a few mainstream manufactures taking notes here and producing similar systems in the foreseeable future.
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Yeah, that's why I wanted to draw all the diagrams with the same criteria for (preloaded) spring length, hammer stroke, and hammer to rear end cap distance.... so we could visualize the pros and cons of the different ideas.... The two designs with the guide remaining stationary at the back require a very deep hole in the hammer (the stroke plus the distance the end of the guide sits inside at rest), so they would require different hammers, I would think.... The two designs where the guide moves with the hammer and supply part of the energy and momentum, both have the same problem at the back, where the stop nut at the back of the guide, which is going to be AT LEAST the OD of the spring (and more if it's actually a nut), has to travel through the gap adjusting bolt, UNLESS there is a ton of room between the hammer and the rear plug....
Having said that, I intend to try the bottom version next, because it is very close to my original design.... All that is different is that sliding collar, and a larger adjusting bolt required so that it can have a larger ID to accommodate the stop nut.... I really like the idea that all the work the spring does gets to smack the hammer, instead of a large percentage of it going to waste.... In addition, the load on the guide stop is tiny, it just has to accelerate the collar at the end of the stroke.... instead of having to stop the mass of the guide and spring.... We can probably do away with the O-ring entirely on the bottom design....
It will indeed be interesting to see over the next few years if any of the manufacturers are paying any attention.... ::)
Bob
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Having said that, I intend to try the bottom version next, because it is very close to my original design.... All that is different is that sliding collar, and a larger adjusting bolt required so that it can have a larger ID to accommodate the stop nut.... I really like the idea that all the work the spring does gets to smack the hammer, instead of a large percentage of it going to waste.... In addition, the load on the guide stop is tiny, it just has to accelerate the collar at the end of the stroke.... instead of having to stop the mass of the guide and spring.... We can probably do away with the O-ring entirely on the bottom design....
Bob
If I understand the bottom design ... the Entirety of the spring / rod unit is floating upon strike of valve. Gap could be Stop rod to hammer or Stop rod to rear cap ?
The WEIGHT of the spring & rod in terms of momentum to valve add to that of hammer, yet due too them floating just prior to impact ... will they contribute to the strike energy or rebound/bounce around absorbing some ???
Minds pondering that one ???
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Having said that, I intend to try the bottom version next, because it is very close to my original design.... All that is different is that sliding collar, and a larger adjusting bolt required so that it can have a larger ID to accommodate the stop nut.... I really like the idea that all the work the spring does gets to smack the hammer, instead of a large percentage of it going to waste.... In addition, the load on the guide stop is tiny, it just has to accelerate the collar at the end of the stroke.... instead of having to stop the mass of the guide and spring.... We can probably do away with the O-ring entirely on the bottom design....
Bob
If I understand the bottom design ... the Entirety of the spring / rod unit is floating upon strike of valve. Gap could be Stop rod to hammer or Stop rod to rear cap ?
The WEIGHT of the spring & rod in terms of momentum to valve add to that of hammer, yet due too them floating just prior to impact ... will they contribute to the strike energy or rebound/bounce around absorbing some ???
Minds pondering that one ???
That's to be tested. As part of the spring is not accelerating or accelerating at lower rate the SSG combo could follow the hammer a millisecond or few milliseconds behind it. If it does then the effect will depend on the timing it strikes the hammer. If it's short enough it will add dwell, if it's longer it will hit the hammer on rebound and kill the bounce.
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My guess is that the guide and spring assembly will travel as a pair with the hammer and add to the impact.... Don't forget that they are still together when the guide hits the (very light) stop, at which time the gap begins to open to about 0.020" (or whatever you set it at), and even if they came apart over that distance, the hammer then hits the valve and immediately slows down, and the guide catches up with it again.... before the poppet even has a chance to decompress and leave the seat would be my guess (it has to travel a few thou just to decompress).... The entire round trip for the valve (dwell) from beginning to end is only about 1 mSec (plus or minus) during which time it has to lift 1/16-1/8" and then close again.... so I don't think there is any question the guide will be travelling with the hammer from the time the valve opens until it closes.... After that, you are correct that you have two pieces rattling around loose, the hammer and the spring/guide assembly....
Bob
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Hi Bob , just an idea to run past you, been thinking down these lines for a while , but as I am now retired I have no access to machines to try it ,,
If we were to drive the hammer using two strong opposing magnets cotained in a plastic sleeve so little friction , the rear magnet could be on a adjusting rod ,
once out of raange of the rear magnet this would act like the slingshot idea but no spring to bounce it back,
what you think ? , also thanks to you and other members for some great ideas and reading, it keeps the grey stuff ticking over ,
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I think that since magnetism drops off so quickly with distance it would not be suitable for the hammer stroke we need.... Also, it would be extremely hard to cock that last few millimeters.... Electronic solenoids have been used in lower powered guns, but they have an actual stroke distance under power.... I'm not so sure that if you had a permanent magnet strong enough to do the job if it wouldn't be just as prone to bounce as a spring anyway....
Bob
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Original .25 Mrod was tuned BLT @ 2500 to 1800 fill avg 760fps 24 shots @4% spread and very evident hammer bounce burping. Not having the tap to thread end cap I drilled out the original spring tensioner to 1/4" the size of the bolt used for the spring guide. Used steel brake tubing as a sleeve to center original 6# spring. Removed stroke screw and installed set screw flush with hammer face and not protruding into hammer cavity. Shaped bolt head and polished guide for smooth cocking. Its about as simple as it gets and very effective, not to mention cheap.
Now @ 2300 to 1600 fill avg 750fps 40 shots @4% quieter and no burping, nice sharp pop sound. I fill with scuba or hand pump so this is perfect for me. I use it for small game and varmints so 31fpe is even overkill. Trajectory is predictable with a mil-dot scope.
Cat skinned successfully.
(http://i447.photobucket.com/albums/qq194/zaphod621/Mobile%20Uploads/IMG_20160110_171728_026_zpsngkn3gtx.jpg) (http://s447.photobucket.com/user/zaphod621/media/Mobile%20Uploads/IMG_20160110_171728_026_zpsngkn3gtx.jpg.html)
(http://i447.photobucket.com/albums/qq194/zaphod621/Mobile%20Uploads/IMG_20160110_171919_776_zpsr7ka345m.jpg) (http://s447.photobucket.com/user/zaphod621/media/Mobile%20Uploads/IMG_20160110_171919_776_zpsr7ka345m.jpg.html)
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Hi guys, new to the forum and relatively new to modding, so please forgive my limited understanding.
I keep going back to bstaley's idea of the guide rod going through the hammer. What if the striker on the front of the guide rod were large enough in diameter- say, half the diameter of the hammer- that when the hammer is at rest, the striker being flush and sprung against the front of the hammer would be enough to keep the guide rod aligned. Then you wouldn't have to have a long channel to keep it aligned. You could literally use a prod hammer drilled through for the guide rod. True, you would loose a little hammer travel to the thickness of the front of the striker, but it wouldn't have to be that thick... maybe 0.1". You could gain that in other places, like taking it off the back of the valve stem, or maybe if the front of the hammer is meaty enough you could countersink the striker into it. The step inside the hammer only needs to be strong enough to retain the spring at full cock-it doesn't have to sustain any impact. When you cock the hammer, the rear cap and the small hole in the hammer will keep the guide aligned.
On my 2250 I am using a disco hammer spring and an RVA from a 2300S. With the RVA adjusted all the way in, plus about .050" worth of lip on the spring guide, it's still not at coil bind. There should be plenty of room for a stop nut in there. I don't know how much preload that gives me, but I know it's enough to hold the valve open when not charged.
Besides being compact, with no rod out the back to pinch fingers, it also allows you to adjust the spring tension without affecting the gap. If your RVA was large enough, you could screw it out, slide the guide rod out the back, adjust the spring tension nut, and re-set the RVA(which now is the gap adjustment) without further disassembly. True, you would loose some velocity when the hammer picks up the guide and spring, but you gain their momentum. In the original design you loose velocity by accelerating the guide rod/spring/nuts and then loose their momentum before the strike. It would be interesting to see how the two hammer strikes compare. And you would have to mod/replace the hammer, but many of us have to do that anyway when we put a better trigger group on our 22xx or discovery.
Brandon
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Not sure how you can adjust the preload without affecting the gap.... To increase preload, you have to shorten the distance between the front and rear stop nuts, so you then have to screw the RVA / gap adjuster back in by the same amount to compensate.... unless I'm not understanding something....
EDIT: I understand now, it is the end of the guide that hits the RVA, the stop nut can be anywhere ahead of that, so changing the preload won't affect the gap....
Bob
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Just read the thread and pick up on the earlier thoughts shared on WEIGHT that hammer spring must move tho have no effect on actual strike energy, and the need for enough strength of the stop rod being able to tolerate repeated impacts of decelerating the stop rod components. ( Think small jack hammer ) and build accordingly.
Have fun !!
Heh... I found this thread when the conversation was already two weeks in... I am reading through from the beginning, but am only at post 100 or so, and this thread is on fire! I want to absorb as many ideas as I can before doing this, as I see that a lot of variations on this idea have been put forth. I got a lot of reading to do!!!
Here are all the major variations of the SSG that have been invented so far....
... Aaaand once again, thanks to Bob for being a heckuva guy!!!
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In this setup, the front "stop nut" is actually the striker, which is actually just the end of the guide rod. The other end of the guide rod goes all the way back to the RVA which sets the gap. You could actually get away without an RVA- just measure from the valve stem to the rear cap, subtract the gap, and cut it to that length. One drawback to this system is you can't independently adjust the preload and cocked spring tension. As one goes up, so does the other. Hope I'm not missing something obvious LOL!
Brandon
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Bob, your not missing anything,
Since I used the original spring tensioner and drilled it out with a 1/4" bit some of the original apex flats remain, enough to still be able to adjust the pre tension but I have to take out the end cap and remove the guide to make adjustments, a pita to be sure. I just happened to luck out and can adjust the length with the jam nuts and still be at my chosen speed before hammer bounce occurs, but its close I can increase speed by backing out jam nuts to about 770 fps before i begin to hear the tell tale burp. When I backed jam out all the way was getting about 825fps and all kinds of bounce. Have not tried increasing preload yet to see where that takes things. I am just thrilled with how it shoots now, for now. Never leave well enough alone.
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I went back and included the bstaley suggestion in the compilation in Post #356.... my apologies for missing it the first time around.... :-[
Bob
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Now @ 2300 to 1600 fill avg 750fps 40 shots @4% quieter and no burping, nice sharp pop sound. I fill with scuba or hand pump so this is perfect for me. I use it for small game and varmints so 31fpe is even overkill. Trajectory is predictable with a mil-dot scope.
Cat skinned successfully.
So you are over 31FPE with an efficiency of 2.0 FPE/cuin? Doesn't seem possible, Mrod's in .25 will be flying off the shelves
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Zaphods 2.0 efficiency is plausible.
Heck, I am already hovering around 1.8 efficiency with a 25 to 30 fpe tune in .22 cal using a short stiff spring with a few other changes.
Add a sort stiff hammer spring or SSG, a heavier than stock poppet return spring and port correctly will get you in the efficiency range of 1.5 and greater.
And you are right,
Mrods should be flying off the shelf with that kind of marketing/perfromance. Unfortunately, crossman doesn't have mad scientists like us working at their facility.
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Tons of great info on this mod (tons of it over my head :o) wondering when the YT videos are gonna start popping up on how it's being done and results...
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I correct my speed, it is 750fps peak not average. Low was 720 and average was 740 with a total of 43 shots. I got over 5 magazines with this fill. Another correction my fill was 2500 down to 1500, I wrote down the guns gauge instead of the tanks correct gauge. Gun is about 200psi off. I wrote down 2300psi when i was within 2% of peak for 30 shots down to 1600psi. Sorry for the confusion but still an impressive improvement.
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Before a mfgr makes this available it will have to be be pleasing to the eye and hand. I love the idea and will implement it, but most of what I have seen are not attractive.
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I correct my speed, it is 750fps peak not average. Low was 720 and average was 740 with a total of 43 shots. I got over 5 magazines with this fill. Another correction my fill was 2500 down to 1500, I wrote down the guns gauge instead of the tanks correct gauge. Gun is about 200psi off. I wrote down 2300psi when i was within 2% of peak for 30 shots down to 1600psi. Sorry for the confusion but still an impressive improvement.
OK so now it's 1.47...........a bit more believable to go from 1.24 to 1.47 and not 1.24 to 2.0
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I really like the idea that all the work the spring does gets to smack the hammer, instead of a large percentage of it going to waste....
Bob
Bob,
How much is required for this weight to be, 'large'? With an AL guide( that is at present waaay to long), and two 10-32 nuts, I have 120 grains, or roughly 8 grams....about 10% of the marauder hammer.
cheers,
Douglas
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I have only used steel guides, that are as large as I can get to slide freely in the spring.... so they are a pretty big percentage of the total weight.... Obviously with the original version, the less the guide assembly weighs, in relation to the hammer, the better.... That is one of the reasons I want to try the last version I drew in Post #356.... I frequently use spring guides that ride with the hammer, with a front the same as we are using now, captive between the hammer spring and hammer.... and those add to the weight of the hammer, increasing dwell, which in the more powerful guns I am often chasing, helps.... That version will share that advantage....
Bob
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On that note ... As i'm tweaking original small screw diameter stop rods have incorporated Acetal Spring I.D. guides.
It is nothing more than a fitted to spring I.D. sleeve with a shallow shoulder spring seats against. Placed at REAR against end cap so it remains stationary. It's length adjusted so upon spring compression during being cocked it does not interfere with hat holding spring at hammers end.
This has fully controlled spring cant and vibration allowing stop rods size/mass to remain very small.
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I got the .224 running with the SSG. Plastic rear nut to the end cap, and 2x 1.5", .059 springs at .420 OD. Without going nuts on preload it shoots quite consistently at 960 fps using 225107, 40 gr slugs. It is more accurate than I remembered; few sighters, and I drilled a 9V battery right in the middle at 50 yards. Going to try it on the squirrel population reduction program tomorrow...:)
I will also run a string and see how the numbers look with a 23" barrel.
cheers,
Douglas
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I thought maybe this may help with some of the SSG designs.
https://www.google.com/search?q=recoil+spring+guides&biw=1454&bih=680&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwjA--T5lbHKAhXEOj4KHTGmDjEQsAQIIg#imgrc=_ (https://www.google.com/search?q=recoil+spring+guides&biw=1454&bih=680&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwjA--T5lbHKAhXEOj4KHTGmDjEQsAQIIg#imgrc=_)
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I rebuilt the first gun (2260/Disco) I converted to the SSG today, using the last drawing in Post #356 above.... It uses a much shorter spring guide that moves with the hammer, so the energy is not wasted.... Here are the two types.... I stole the spring from the top one for the new one, on the bottom....
(http://i378.photobucket.com/albums/oo221/rsterne/Parts%20for%20Sale/Disco%20New%20SSG_zpsonjpztnd.jpg) (http://s378.photobucket.com/user/rsterne/media/Parts%20for%20Sale/Disco%20New%20SSG_zpsonjpztnd.jpg.html)
The top one has a long guide that stops when the rear nuts hit the gap adjusting bolt.... The bottom one has a much shorter guide, with a sliding aluminum collar that pushes against the end of the gap adjusting bolt when you cock the gun.... and the stop nut slides back inside the adjusting bolt.... When you fire, the guide accelerates with the hammer, and just before it hits the valve, the stop nut hits the collar and carries the collar with it.... All the moving parts provide their energy to the valve.... The gap adjusting nut must be larger in diameter to allow the stop nut to pass through the center when the gun is cocked.... The collar is centered in the front of the end plug, which keeps everything aligned.... You can see how much shorter the new setup is than the original, and when cocked, the stop nut stays inside the gap adjusting bolt, as in the photo below....
(http://i378.photobucket.com/albums/oo221/rsterne/Parts%20for%20Sale/Installed%20and%20Cocked_zps8e76soqx.jpg) (http://s378.photobucket.com/user/rsterne/media/Parts%20for%20Sale/Installed%20and%20Cocked_zps8e76soqx.jpg.html)
The photo above is with the gun cocked.... Compare that with the photo below of the original SSG setup, also with the gun cocked....
(http://i378.photobucket.com/albums/oo221/rsterne/Discovery/Preloaded%20Spring%20Guide%20Cocked_zpsqtzb0nsb.jpg) (http://s378.photobucket.com/user/rsterne/media/Discovery/Preloaded%20Spring%20Guide%20Cocked_zpsqtzb0nsb.jpg.html)
There is no longer a pinch point to worry about, and it looks MUCH nicer and more compact....
How does it work?.... FABULOUS !!!.... When I first assembled it, I used 0.1" less preload than I did in the original version, because I expected a stronger hammer strike and I didn't want to go past where I wanted to end up.... Well, it turned out I should have reduced the preload by 0.2", because I had more velocity than I wanted from the heavier hammer strike.... When I cranked it up (with no gap) it was well over 1000 fps with Kings, and I just happened to have some of the new 34 gr. King Heavies here, so I tried them.... With a minimum gap I was in the mid 800s, which was 55 FPE, compared to the best I could do with the old SSG with the Kings of 50 FPE.... So, I pulled it apart, increased the preload to maximum with the 2200 spring, and was rewarded with even more velocity.... By maxing out the spring to coil bind (preload, no gap), I hit 948 fps (68 FPE), which is harder than this gun has ever shot before.... Once I backed it out to get a tiny gap, it was shooting right at about 900 (62 FPE), but it was using a lot of air, so I backed it out another turn, and settled for a peak velocity of 880 fps with a 5-shot string from 2000 psi down to 1300.... The average was 866 fps (57 FPE), at an efficiency of 1.30 FPE/CI.... which is pretty astounding for a mildly modded Disco with the small tube from a 2260....
I really like this version of the SSG, particularly for guns where you need lots of hammer strike to get the dwell for high power with heavy pellets.... It still has the advantage of eliminating hammer bounce, but it doesn't waste the energy the spring puts into the guide, instead it uses the weight of the guide to increase hammer strike and dwell.... In addition, it is much more compact, and the guide can be hidden inside the adjuster, providing the hammer stroke isn't too long (this gun is 0.65").... All in all, I think it's a significant improvement over the original.... particularly for higher powered PCPs....
Bob
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Since the spring assembly is now traveling with the hammer, there would be no reason the hammer spring assembly could not be built into the hammer assembly with the same kind of results. You could possibly thread the spring guide into the hammer and with a cap head the spring preload could be adjusted from the rear without disassembly.
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So HOW do you now adjust spring preload ?
It looks like nut on stop rod would be further tightened .... then collar screw would be tightened down equally until gap distance is in place once more.
Is it that simple ???
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I have tried spring guides that travel with the hammer, they are used in rear-cocking hammers, for example.... There is an example of an SSG like that in Post #356, suggested by I_like_Irons.... It is critical that they be threaded perfectly as they must be 100% concentric with the hammer or they will bind in the rear guide.... Unless required for rear-cocking, I prefer the loose guide, with a shoulder on the front of the guide captured between the end of the spring and the hammer.... I have used that setup a lot.... It adds the weight of the guide to the hammer strike (an easy way to make it heavier to gain dwell), but with no alignment issues.... This version of the SSG has that advantage, plus the spring can be easily removed to change it.... Unfortunately, since the collar hits the rear plug on cocking, you do have to remove the rear plug to change springs, but you don't have to pull the hammer....
Yes, Scott, you adjust the spring preload by how far the stop nut is threaded in towards the front of the guide.... I always have a target in mind, so I just keep threading the guide further and moving the nut down, always tightening it against the shoulder on the guide, until I can hit just over the power I want, and then fine tune with the gpa adjuster (which in this case sets the position of the cocking collar)....
Bob
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I can report that the bstaley design does work! Apparently you have to have at least 20 posts before you can insert pictures, so I will post several short descriptions so that we can get to the photos. The vehicle for this mod is a .22 Crossman 2400kt with an 18"barrel. It has a 17 CI tank regulated to 2000psi, with poly TP and standard valve mods.
TBC
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My pre-mod string was from 2500psi to 2000psi using 14.3 CPHPs. Average velocity of 861 giving an efficiency of .76FPE/CI
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That first test had an Extreme Spread of 26 fps which if I calculated correctly is 2.9%. My post mod string also started at 2500 psi and lost a little velocity-down 40fps to 821. But it more than doubled the efficiency to 1.69 PFE/CI! Way better than I was hoping for. The best part was the usable shot count.
TBC
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I went from 19 shots to 60 with an ES of 32 fps, which I calculate at 3.8% How on Earth did I triple the shot count? I think the regulator setting comes into play
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The regulator was set just in front of the knee of the velocity ark, so that the velocity just started to fall after the regulator pressure was crossed. After the mod, When I shot down past the 2000 psi mark, the velocity started to climb, peak and finally really started to drop after 60 shots, which put me at about 1850 psi. Yeah I know I kinda cheated by using more air, and if I was unregulated I wouldn't have tripled my shots. But I continued the string until the extreme spread made sense to stop.
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On to the build. With my very limited machining skills, making a hammer was by far the most ambitious thing I have attempted. I copied the dimensions of the stock hammer, except I didn't cut a waist into it, as I am using a PROD trigger group.
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I found a rod that just fit through the spring. Actually a tension rod from a snare drum-did I mention I repair instruments during the day?
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Sorry to be posting so much... I really want to show the pics :-) I drilled the hammer to fit the rod, and countersank the head into the front of the hammer.
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The spring cavity measures the same depth as the OEM hammer, so I have the same hammer stroke as before.
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There was no need to make the guide channel longer because the head of the guide aligns the rod when not cocked. Actually I think it could possibly be drilled deep if you needed to make more room for your stop nuts or wanted to use a longer spring.
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I was using a Disco spring, so I had plenty of room.
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I am still using the 2300s RVA, so the back looks very tidy. I also discovered that the RVA doubles as a degasser since the guide rod runs from it to the valve stem.
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Surprisingly enough, after I finished the new hammer, it weighed exactly the same as the old one-58 grams. With the rod, spring, nuts, and cocking pin added, it totalled 71 grams.
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Forgot to mention that the string I shot was with the gap set at 1/2 turn out from touching the valve stem, and the spring just shy of coil bind.
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My next experiment will be to lighten the guide rod by using a much smaller diameter rod with a plastic or delrin sleeve.
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My main reason for trying this method is that I want to use it when I convert my old 1400 to a retained air pumper. If that rifle had a guide rod out the back, I would certainly get pinched more than I want to think about. My son has a hard enough time making a good shot without that to worry about.
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I am truly sorry for dumping posts into this thread, but I'm sure someone out there will want to see the pics. If I have committed a faux pas, please forgive me.
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OK, here are the pics.
(http://i1159.photobucket.com/albums/p630/musquat1/20160116_163241_zpslmgehwog.jpg) (http://s1159.photobucket.com/user/musquat1/media/20160116_163241_zpslmgehwog.jpg.html)
(http://i1159.photobucket.com/albums/p630/musquat1/20160116_163307_zpsbyu4kb2b.jpg) (http://s1159.photobucket.com/user/musquat1/media/20160116_163307_zpsbyu4kb2b.jpg.html)
(http://i1159.photobucket.com/albums/p630/musquat1/20160116_163443_zps9jwqicfz.jpg) (http://s1159.photobucket.com/user/musquat1/media/20160116_163443_zps9jwqicfz.jpg.html)
(http://i1159.photobucket.com/albums/p630/musquat1/20160117_215131_zpse7xmuhih.jpg) (http://s1159.photobucket.com/user/musquat1/media/20160117_215131_zpse7xmuhih.jpg.html)
I removed the pic of my rifle, since it seemed to be taking this incredibly important thread off topic. I thank all who replied for your help and if anyone has any further suggestions feel free to pm me :-)
Brandon
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This is exactly I was looking for my Sumatra. You made my life easier.
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Your post numbers are not increasing, pm Dez to fix it.
Bob
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It is actually 2 nipples and a coupler.
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Do you have any solid numbers on pressure ratings for those fittings? For my part the reaction to seeing that picture was akin to watching a horror film scene, the binary moment of panic coupled with relief that it is on a screen, not near me. Of course if the fittings are rated for a working pressure of 3,000psi then good for you, no likelihood of a hand being torn apart soon. If they're simple brass plumbing fittings... guy, de-pressurize that thing NOW!
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Looks scary to me, too.... Unless you KNOW it's safe, please degass that gun NOW!!!!
Bob
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You can buy safe hydraulic fittings that would easily handle the psi, but those don't look like them. The eight hanging on the elbow puts alot of stress on it.
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You guys are probably right. I don't know about the safety ratings of the brass I used. I will immediately find another way to pressurize it. Thank you guys for looking out for me!
Brandon
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Since the back end of the tank seems to be secured to the grip frame, and the result makes for a handy forearm on the carbine, perhaps you could preserve the setup by switching to a microbore fill hose running from the bottle to the soldered Foster nipple on the valve? Secure the front of the bottle somehow to make it stable for holding and you've dealt with the risk. A good hose will easily handle more pressure than a failed regulator could dump into it. Something like this perhaps:
http://www.bestfittings.co.uk/shopexd.asp?id=160&bc=no (http://www.bestfittings.co.uk/shopexd.asp?id=160&bc=no)
Of course this would leave a big loop... but perhaps someone like BestFittings or some other supplier could make you a reverse coupling to connect to the right length of hose to run straight back into your valve, given the right measurements.
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Thanks guys, I degass after every shooting session, so It's already done. I promise not to gas it up again until I decide on one of the tried and true methods found on these pages. Thanks again!
Brandon
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The increase in velocity as it comes off reg is the typical behavior of hammer stroke that is on the front end of the string( on the increase in velocity as pressure drops).
cheers,
Douglas
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Ok having great results with very little tuning efforts so im going down this road with SSG for production. Its all internal and completely adjustable externally both rod gap and pre-load plus no rod will come out. I will fine tune this tomorrow and post but for now heres what I got. http://airgunguild.com/index.php/topic,11.msg341.html#msg341 (http://airgunguild.com/index.php/topic,11.msg341.html#msg341) Bob would you still consider this and SSG???
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Ok having great results with very little tuning efforts so im going down this road with SSG for production. Its all internal and completely adjustable externally both rod gap and pre-load plus no rod will come out. I will fine tune this tomorrow and post but for now heres what I got. http://airgunguild.com/index.php/topic,11.msg341.html#msg341 (http://airgunguild.com/index.php/topic,11.msg341.html#msg341)
Daaaaannnngggg that's tight! Good job! I imagine if it were tuned to the low 800s the shot count would go up a bit more.
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Actually it would go way up!!! I just want to take a minute to thank Bob Sterne for talking to me on the phone and answering emails etc. and getting my mind thinking in new ways, this little device will save people with no tuning skills tons of time and me tons of time explaing on the phone how to tune a gun. This last SSG will be tested in the FLEX now.
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I think some people think I am crazy for making my ideas public and not trying to profit from them.... but this thread makes me proud.... The SSG idea has really taken off, with a bunch of different versions being made in a very short period of time, some of which will make it to commercial production, and more power to them.... Who knows, some of the major manufacturers may even pick up on the idea to give their customers a higher shot count from the air saved.... IMO, when a good idea is given freely to the public domain for everyone to experiment with, improve on, and talk about, it can grow exponentially, almost taking on a life of its own.... I couldn't be happier.... My sincere thanks to EVERYONE who participated in (past, present and future tense) the development of the SSG....
Bob
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Ok having great results with very little tuning efforts so im going down this road with SSG for production. Its all internal and completely adjustable externally both rod gap and pre-load plus no rod will come out. I will fine tune this tomorrow and post but for now heres what I got. http://airgunguild.com/index.php/topic,11.msg341.html#msg341 (http://airgunguild.com/index.php/topic,11.msg341.html#msg341) Bob would you still consider this and SSG???
PM me the order info I assume this will be compatible with your NBH I just ordered
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It certainly will and testing with the SSG with NBH is happening tomorrow!! I have to order enough springs and retainers to make a production run but thats no big deal. Its on like Donkey Kong!!! Im telling you this thing is SO easy to tune it makes me almost obsolete.
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Far from thinking you're even remotely crazy Bob, I admire the efforts you've made in developing refinements to PCP airguns and the probably even greater amount of time and brain power you've devoted to sharing these innovations, while remaining very open to discussion and improvement. A wonderful example for us all. Amazing what nuts and bolts can accomplish, eh?
I developed the first version of an adjustable and removable neck mechanism for doublebasses about 5 years ago, took it to an international convention in San Francisco and showed it to anyone, entered it into the ISB competition... and so far not one single maker has even bothered to contact me about developing the idea further, nor asking for permission to use it (not that I'm asking for that!). I'm a bit stunned. Of course I'm hardly a household name internationally, but in my region I am 'the guy' bassists come to and recommend to their colleagues. The nut and bolt device I invented makes it easy to dismantle and reassemble a doublebass neck for travel within a few minutes, potentially saving a touring bassist many thousands of dollars per year in over-size airline fees. Of course there are lots of other luthiers and companies making removable necks... but mine is the only design which includes geometry to allow raising and lowering of the strings within a few seconds without affecting tuning, such that large changes in string height can be made on stage between numbers without delaying performances. The added palette of performance options becomes astounding to anyone who understands doublebass performance. But no, every single model continues to involve wholesale retuning after adjustment, delaying performances by half a minute at least, often much longer, so performers really don't bother doing so.
Of course this is in the rarefied world of concertizing doublebass players. I wasn't expecting any big drama. Still, it'd be nice to see a good idea take flight and become adopted generally, especially to see it evolve in the hands of different makers. But sharing the design on my website and in the major discussion forum for bassists hasn't even made a ripple. Oddly, the most interest I've seen is from a few local symphony players, with a couple of them suggesting I should patent the idea and market it. Not interested. Information wants to be free. Thanks for sharing that ethos Bob, you're one of the good guys.
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Travis - what were the starting and ending pressures on that string in the referenced post - I did not see any.
Have you done an efficiency calculation?
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3000 fill pressure but I didnt check it again after running the string to be honest, because I know I can tighten it up a bit with a little tuning. I set it up so the crack speed would be around 850fps at a 3000 fill I made no adjustments after that.
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I have just joined GTA and found this interesting thread and thought I may have something relevant to offer but it requires accompanying pictures. My Photobucket pics are being rejected as "external links", neither is my interpretation of the "Attachment option" accepted.
Perhaps someone can direct me to the appropriate picture posting protocol ....
I think I have found the problem - Required to write 20 posts before permission for pics. That may take some time!.
In the meantime; perhaps chase down pics of the internal workings of the RWS Excalibre/ Tarantulas from back yr 2000. The hammer set-up of mine (and some of the adjustments made to get 10 bar-cc/fpe in 2006) seems to have a number of things in common with Bob's developments.
There is provision for adjusting spring guide rod length to give up to 1/4" free travel before hammer/valve stem contact; the possibility of shorter springs increasing that travel; double counter-wound springs of different loadings can be used, there is a positive stop for hammer travel independent of the hammer/valve interaction. The latter can be spring loaded to counter any hammer bounce tendency. There is no external feature.
Cocking is odd for those not accustomed as it is on the forward/ closing stroke.
If Bob or others are familiar with these quite different hammers, perhaps he/they could elaborate the differences in concept to the developments within this thread. ... Kind regards, Harry in OZ.
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this is awesome
i joint this forum cause i read this mod
thanks for sharing this gr8 method really appreciate
and i already make my own ssg based on original ssg setup, and it work so great on my PCP
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I'm playing with a SSG and getting great results on my .25 Mrod. One will be going into my brother's gun and .177 Mrod shortly.
Thanks so much Bob for sharing this with us!
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HI Harry, and welcome to the GTA.... I'm sure you realize that I have only be involved in airguns since 2007, and no, I am not familiar with the guns you speak of.... so it doesn't surprise me that this could easily be a case of "parallel development", at least to some degree.... It is strange that so great a concept would have been lost to time for a decade and a half before being rediscovered, if that is indeed the case, however.... Like many, I have been through the process of using short, heavy hammer springs, and while they can improve efficiency, they do make the gun harder to cock.... and from what I have seen, do not reach the efficiency levels we are seeing with the SSG.... That is not an issue on a lower powered PCP (for example the 12 FPE models common in England) it can sure be an issue with some of the powerful guns we have today, particularly the Big Bores.... It is interesting that your idea required "cock-on-close", I look forward to seeing the photos/drawing once you can post them.... Might be a great concept for a QB7X?....
For those of you who do not know of "Harry in OZ".... you should.... Turn his name backwards, any you may recognize it.... "yrrah" is the name Harry Fuller goes by on the Yellow, and I for one really look forward to hearing what he has to say on this, and any other topic, on Airguns.... He has probably forgotten more about airguns than I will ever know....
Bob
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Thank you for the welcome Bob.
I have pics of the Excalibre unit for posting and can take more if necessary. It was an Axsor/FX design. I guess it will just have to wait until I am able to post pics to show what features may and may not be common to your own design and concept.
I think we missed your valley in our wanderings around BC about 50 years ago. What magic country! Didn't see a blue simian Sasquatch either :'( .
And thank you to Smoketown for his suggestion re- the 20 post rule.
Kind regards, Harry.
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Harry, if you want to email them to me, I can host them in my Photobucket account and post them for you.... send them to....
bob at mozey-on-inn dot com
Bob
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Harry, if you want to email them to me, I can host them in my Photobucket account and post them for you.... send them to....
bob at mozey-on-inn dot com
Bob
I may do that tonight (here) Bob. We are just getting ready for a funeral service and may be engaged for some time.
There could be 4 or 5 pics and they may require re-sizing here or there. Thank you for the offer.
I am now up to 7 posts with the thank you notes! ... Best regards, Harry.
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I am still trying to find any extra minute to work in the garage to finish this up to test an apples to apples comparison between the short stiff spring and SSG.
For some reason I just can not get that "crunchy" feel out of cocking. I know it's my machining/design as I have no time and I am rushing it with the little time I do have.
Anyway,
This design seems to be the smoothest without a stud or bolt sticking out when cocked. Still needs sizing so it is work in progress but better than my three past builds.
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Shorty I really like that design! Looks like you need to sharpen your lathe bit and toss on some cutting oil. Nice compact externally adjustable set-up thats sweet
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I am out of carbides as I broke 2 of them trying to turn down some case hardened 1/2 X 20 bolts and one of them learning how to thread SS instead of soft aluminum on the cheap old crappy 7X10 chinese lathe.
I am still learning with the lathe and grinding HSS tools. ;D
Sure is a heck of a lot easier and prettier when I cut and turn plastic or aluminum. Hey, the brass plug turned out fairly nice and pretty. ;D
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Don't feel bad shorty, I am now considering soaking one of my carbide inserts in hot TSP solution to remove the welded on bit of aluminum I put on its tip turning down the 'threaded nail' for my SSG. I turned it around before making the spring cap nut/guide from Acetron plastic. I even did the threading with a bit made of cast super alloy( a Rexalloy competitor to 98M2 Stellite ). Got some very nice threads from it...:)
I need a better bump stop; the 70D Harbor Freight-kit O-Ring smooshes out at the preload I am running( two 1.5" x .420 x .059 wire with nearly 3/4" of preload ). It does make a nice friction bit for that plastic nut though...:)
I need to get home early enough to run my chrony and post a string from that Marauder. It may be in the mean time I will make a second SSG for the .25 I so enjoy shooting King Heavies with.
cheers,
Douglas
the .224 Marauder, prior to barrel shortening and SSG installation
http://www.gatewaytoairguns.org/GTA/index.php?action=media;sa=media;in=3236;preview (http://www.gatewaytoairguns.org/GTA/index.php?action=media;sa=media;in=3236;preview)
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I was getting a similar "crunchy" feeling in my early experimenting. It ended up being the coils of the spring rubbing against a threaded portion of my guide rod. Is the inside of where the spring travels threaded? It's hard to tell from the photos, but it looks like there's no smooth spring guide to keep the spring aligned. Perhaps drilling through your spring tensioner and running a spring guide through it would get rid of the crunch. Just a thought
Brandon
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Need help finding a spring for the SSG heres what I need approx. 2.5 long -wire size.050-.052 -OD.350 to .040 Ive looked in the normal go to but no dice.
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Need help finding a spring for the SSG heres what I need approx. 2.5 long -wire size.050-.052 -OD.350 to .040 Ive looked in the normal go to but no dice.
Travis, have you checked McMaster-Carr?
BZ
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Yes
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If they don't have it nobody does! :P. Man, I have sourced much from them when I had my race bike.
BZ
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Here's a good resource for springs and calculating.
http://www.thespringstore.com/index.php/spring-calculator.html (http://www.thespringstore.com/index.php/spring-calculator.html)
Looks like they may have something real close in stock for you. I just do not know what the minimum purchase is.
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Century Spring.... all are 0.36" OD x 2.5" long
#71235 (Music Wire) - 0.051" wire - 18 lb/in.
#71235S (Stainless) - 0.051" wire - 15 lb/in.
#12463 (Spr. Steel) - 0.050| wire - 15 lb/in
http://www.centuryspring.com/Store/search_compression.php (http://www.centuryspring.com/Store/search_compression.php)
Bob
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Need help finding a spring for the SSG heres what I need approx. 2.5 long -wire size.050-.052 -OD.350 to .040 Ive looked in the normal go to but no dice.
what rate? ID and OD?
-OD.350 to .040 ?? I assume 0.35 to 0.40 inches?
-ID would be 0.30? or do you want 0.25?
Those flat wire springs I sent you pointers to should work - ID 0.25 but I am sure the OD is at 0.4 or a bit more.... I can check.
But what rate do you want?
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"Standard" springs are typically the correct OD to fit loosely in a common drill hole.... 0.30" for 5/16", 0.36" for 3/8", 0.42" for 7/16", and 0.48" for 1/2".... The ID is then dictated by the wire size, by the formula ID = OD - (2 x WS)....
Bob
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Bob,
Hopefully I have succeeded in sending you a readable email with pics that can be opened.
Let me know if they need to be sent as attachments. ... Regards, Harry.
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Take a look on this link and tell me if is something interesting.
http://www.hennlich.sk/uploads/sk_Hennlich_tlacne_pruziny_01.pdf (http://www.hennlich.sk/uploads/sk_Hennlich_tlacne_pruziny_01.pdf)
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Need help finding a spring for the SSG heres what I need approx. 2.5 long -wire size.050-.052 -OD.350 to .040 Ive looked in the normal go to but no dice.
the flatwire springs I showed you should be 7/16th (0.4375) inch OD and 1/4+ a hair inch ID.
the shorter one is 3 inches long - the long one is 5 inches (I think).
http://www.egwguns.com/index.php?p=product&id=105 (http://www.egwguns.com/index.php?p=product&id=105)
these should be a little smaller in OD IIRC. I don't have one to measure.
http://www.glockstore.com/custom-parts-amp-accessories/flat-wire-recoil-springs (http://www.glockstore.com/custom-parts-amp-accessories/flat-wire-recoil-springs)
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I am still trying to find any extra minute to work in the garage to finish this up to test an apples to apples comparison between the short stiff spring and SSG.
For some reason I just can not get that "crunchy" feel out of cocking. I know it's my machining/design as I have no time and I am rushing it with the little time I do have.
Anyway,
This design seems to be the smoothest without a stud or bolt sticking out when cocked. Still needs sizing so it is work in progress but better than my three past builds.
I was thinking of similar thing without the endcap. Telescoping rod that compresses the spring and just replaces the existing hammer spring. I was considering a drilled out M8 bolt (bolt head holds the spring) and a long M3 bolt or 3mm rod that slides inside the M8 bolt.
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So my first failed attempt at making an SSG (Bob's original design) was on the original end cap that came with my HPA modified 2400kt. I do not have a lathe, so I used my old drill press. First, I drilled the hole through the bolt slightly off center, but I was thinking I would go with it anyway. Then, I ended up tapping the hole I drilled into the cap so crooked it totally ruined the piece. After that, I just drilled the degasser threads out of my Challenger RVA. A 3/16 drill bit fits absolutely perfectly for this purpose. The end result was a perfectly smooth hole that looks like it never even had threads tapped into it. I used 3/16 steel rod and died some threads on both ends for the nuts. I figured I would post this for those who lack a lathe (me) or who are inexperienced with machining (also me) to be able to make a functional SSG with caveman tools. I think the Challenger RVA is like 12 bucks from crosman, everything is is already centered perfectly, and the job can be done pretty quickly.
So, the way I have been tuning this is to start with the gun uncocked, and the RVA turned all the way in, then back it out by a half a turn at a time until the gun will cock. Once the gun can cock and fire a few times without fail, I then turn the preload adjusting nut in until I just start feeling gap. I eyeball the gap by resting the gun on the end of the barrel and seeing how far I can lift the hammer and drop it. I do not bother to measure anything, I just figure on keeping the gap between 1/8 and 1/16 of an inch. Does this sound like a sensible way to set up an SSG to you guys? I will admit that I have not read every post in this thread, as it is approaching epic lengths and it would take me quite some time, so I apologize if this has already been covered. Is there a better way? How do you do it?
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On the two Crosmans I've made SSG's for (same style as Bob's original version as both have 1" aluminum pipe stocks slipped on, so no worry about the protruding rod and nuts) I just wind in the outer adjusting bolt until the inner nut (I install 2 10-32 nuts to lock against each other) until I see a bit of lift as the rod runs into the hammer. Then back off however many turns. Works at whatever adjusting bolt depth. Of course at some depths with some springs I bottom out, too much preload so the spring is completely collapsed. Then it's time to either swap springs or cut off a turn or two of the spring and try again. I have a tiny TAIG lathe to play with and that really helps, but can see it being more or less practical with a drill press provided it doesn't wobble too much. Like mine. I have a cheap Hitachi drill press with about 0.005" or more run-out. Irritating as heck. Got to replace that thing some day...
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If the gap adjusting bolt turns easily, you can "feel" the point at which the guide/hammer touches the valve.... and if you continue to screw it in, a gap will appear at the O-ring under the rear preload stop nut.... I find the point where there is no gap, and then turn it out from there 1/2 turn (0.020") minimum.... If the velocity is too high, I back it out more.... If you have to back it out 1/8" or more, you have too much preload and can reduce it and make the gun easier to cock....
Bob
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I have been in email contact with OZ Harry (Fuller) about what he did a decade ago on his Excalibre.... I'm waiting for a couple more pics so that I can put them all together so you can understand the system.... In the meantime, I'll try a short verbal description....
1. The hammer, with a screw-in spring guide (to adjust preload), and spring, live inside a "cage" which is withdrawn by the bolt to latch the back of the spring guide (which has a collar for the purpose) onto the sear....
2. Once the sear engages the collar on the end of the spring guide, preventing it and the hammer from moving forward, when you close the bolt, it moves the cage forward, compressing the spring....
3. On firing, the sear releases the end of the spring guide, and it and the hammer are flung forward by the spring to open the valve.... So far, nothing unusual....
4. What Harry did was use a short, stiff spring to create a gap between the hammer and valve stem.... Again, we've seen this before.... However....
5. He used either a light spring, or a series of O-rings, on the back of the spring guide, to withdraw the hammer after firing, and prevent it from bouncing.... and in doing so achieved stellar efficiency....
I hope I have the description correct, Harry.... I tried to simplify it as much as possible.... The difference I can see between this and the SSG is that I am using a large amount of preload, and a gap, to prevent the hammer, when flung back by the valve stem, storing any energy in the hammer spring.... You are using a short, stiff spring with a gap, and then containing the rebound hammer energy with a second spring (or O-rings).... As I said, photos to follow....
Bob
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Here are the photos of the Excalibre hammer assembly.... First, what it looks like stock, on the outside.... The hammer that strikes the stem is on the left....
(http://i378.photobucket.com/albums/oo221/rsterne/Parts%20for%20Sale/Excalibre%20Hammer%20module%2003_zpsj7ojoh1n.jpg) (http://s378.photobucket.com/user/rsterne/media/Parts%20for%20Sale/Excalibre%20Hammer%20module%2003_zpsj7ojoh1n.jpg.html)
Next, the parts inside the cage....
(http://i378.photobucket.com/albums/oo221/rsterne/Parts%20for%20Sale/Excalibre%20hammer%20apart_zpsyfuq0e41.jpg) (http://s378.photobucket.com/user/rsterne/media/Parts%20for%20Sale/Excalibre%20hammer%20apart_zpsyfuq0e41.jpg.html)
The end of the hammer that hits the valve stem is on the right.... It threads on the guide, as does the part that catches the sear on the left.... The preload can be changed by the length of threads on the guide.... The Nylon collar acts as a cushion.... The large sleeve is a "cage" that is pulled back by the bolt carrying with it the hammer and sear catch until the sear engages.... then slid forward again to compress the spring and the bolt handle locked down (cock on close).... The stock spring is on the right, with some that Harry was using on the guides.... He tried various combinations.... The next two photos show some of those....
(http://i378.photobucket.com/albums/oo221/rsterne/Parts%20for%20Sale/Excalibre%20Hammer%20module%2002jpg_zpsp5o1xjvo.jpg) (http://s378.photobucket.com/user/rsterne/media/Parts%20for%20Sale/Excalibre%20Hammer%20module%2002jpg_zpsp5o1xjvo.jpg.html)
You will notice in the photo above that the hammer is recessed various distances (compare to the first photo, where it is slightly proud) because the shorter spring allows a gap....
(http://i378.photobucket.com/albums/oo221/rsterne/Parts%20for%20Sale/Excalibre%20Hammer%20module%2001jpg_zpsdzdshmct.jpg) (http://s378.photobucket.com/user/rsterne/media/Parts%20for%20Sale/Excalibre%20Hammer%20module%2001jpg_zpsdzdshmct.jpg.html)
Harry tried various arrangement of springs and O-rings to retract the hammer and prevent bounce, as above.... The result was excellent efficiency by the elimination of hammer bounce.... he achieved 10 barcc/FPE = 1.64 FPE/CI a decade ago.... Here is the Valve and Hammer assemblies....
(http://i378.photobucket.com/albums/oo221/rsterne/Parts%20for%20Sale/Excalibre%20Hammer%20module%2004%20jpg_zpspwsvdnyj.jpg) (http://s378.photobucket.com/user/rsterne/media/Parts%20for%20Sale/Excalibre%20Hammer%20module%2004%20jpg_zpspwsvdnyj.jpg.html)
and the Valve and Hammer (stock) disassembled....
(http://i378.photobucket.com/albums/oo221/rsterne/Parts%20for%20Sale/Excalibre%20Hammer%20module%2005%20%20jpg_zps6qillhzz.jpg) (http://s378.photobucket.com/user/rsterne/media/Parts%20for%20Sale/Excalibre%20Hammer%20module%2005%20%20jpg_zps6qillhzz.jpg.html)
and the beautiful Excalibre....
(http://i378.photobucket.com/albums/oo221/rsterne/Parts%20for%20Sale/Excalibre%20upright_zpsh9j9pw1s.jpg) (http://s378.photobucket.com/user/rsterne/media/Parts%20for%20Sale/Excalibre%20upright_zpsh9j9pw1s.jpg.html)
Bob
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What about higher power with say a .25 marauder. Is it possible to go higher power but still get the advantages of the SSG? 60-65fpe? I'm getting a marauder in .25 the next couple weeks and was looking into a 10# spring and a WAR valve. Also I thought I read all of this thread and I haven't found what SSG stands for. Sorry so many questions.
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I have also not read the entire thread, but as I understand it, hammer bounce tends to be more pronounced at the higher powers, so the SSG would benefit these guns even more.
SSG=Stopping Spring Guide.
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What about higher power with say a .25 marauder. Is it possible to go higher power but still get the advantages of the SSG? 60-65fpe? I'm getting a marauder in .25 the next couple weeks and was looking into a 10# spring and a WAR valve. Also I thought I read all of this thread and I haven't found what SSG stands for. Sorry so many questions.
Shortly I will post data on my 85 FPE, .22 Marauder, recently outfitted with an SSG. Sooner, if somebody can bring back summer daylight hours...LOL
cheers,
Douglas
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I have also not read the entire thread, but as I understand it, hammer bounce tends to be more pronounced at the higher powers, so the SSG would benefit these guns even more.
SSG=Stopping Spring Guide.
Have witnessed gains on BOTH high and low power guns using the SSG devise.
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^X2
Bob
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x3 no doubt
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I added more photos to Post # 456 about Harry's Excalibre....
Bob
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What page Bob this thread has become massive
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Page 23, middle....
Bob
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Has anyone ever reached 2.0FPE/ci ???
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Yep, it's been done, but rarely.... Usually only in low powered PCPs, and easiest to achieve if you use tiny sips of high pressure.... When a PCP is set up that way, you would think it is fully shrouded, but it doesn't need one.... Guns like a 12 FPE FT rifle in .177, or a 10M match rifle sometimes hit that level of efficiency....
Bob
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So a .25 cal 40fpe gun would be really rare. I'm so so close Bob and I think I have the final piece of the puzzle. Tomorrow I'll send you a string.
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That doesn't surprise me.... I think I was close during some of the SSG installations I have done, but when I cranked the velocity back up to the final tune I wanted I didn't quite make it.... but with a 50% improvement over previous I didn't really care.... It won't be long before we start seeing 1.5 FPE/CI as the new standard instead of 1.0-1.2.... so it just makes sense that instead of thinking 1.5-1.7 as being outstanding, we won't get excited until we push close to or exceed 2.0 FPE/CI....
Bob
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I added more photos to Post # 456 about Harry's Excalibre....
Bob
Bob or Harry, Does the Excalibur have a handle on the hammer assembly, and a separate bolt handle, also?
Thanks,
Lloyd
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Google image search turned up a few pics of the other side....this was a nice one. 8)
(http://i209.photobucket.com/albums/bb30/Ian_HJ/00001-5.jpg)
Al
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I'm guessing the crescent shaped slot in the rear top of the hammer "cage" drags a bolt back with it to work the magazine and load the chamber....
Bob
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Hey Guys,
Irregardless of its efficiency, that's one beautiful gun!!! 8) :D
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I'm guessing the crescent shaped slot in the rear top of the hammer "cage" drags a bolt back with it to work the magazine and load the chamber....
Bob
Bob is spot on. Why am I not surprised?
The loading shaft has a latch which fits that other slot. When it is pulled back out through the magazine there is also a little spring loaded finger/lever operated to pivot and index the magazine. Then the forward cocking stroke allows for the next pellet to be loaded. In all the tens of thousands of shots mine has never malfunctioned. The new Polymag shorts also function perfectly.
SG, that stock on my Excalibre page 23 is grade 3 Turkish walnut. They did come with grade 4 too!
I want to publicly thank Bob for his time and effort in presenting those pics and in succinctly summarizing my explanations so accurately.
Thank you Bob.
Regards to all, Harry.
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I got a string measured, 10 shots long, 82 fpe average, and used 300 psi, or 1100 ci of air. SSG gap of .050-.060", velocity centered on 965 fps and 40 gr cast boolits from a 225107 mold. That is ~.75fpe/ci with a 23" barrel. I was hoping for better...:( I lost my notebook I kept track of this one with, so I can't provide data for a proper conversion. I remember its string being longer, but also using more air( larger delta-P) with the standard spring installed.
cheers,
Douglas
Was having some issue with such a poor result, and ran a few more strings. Took an average of air consumption, and got a result 50% higher...not so bad anymore. Threw out highest and lowest...LOL
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OZ Harry I laughed when I seen Wollongong, thought you were joking but wife is from NZ and said she has been there. David
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Bob, thanks for sharing this mod! It totally transformed my crosman 1377 pcp. I'm using a very soft valve spring... Only 200gram...and hammer bounce was a real issue.
With the SSG it's all but nullified.
Efficiency went from 0.8 to 1.57 fpe/ci.
Shot string from 1600 psi to 1340psi.
10.34 jsb's. Un regulated... Just a quick shot string with the transfer port fully open.. 4mm...barrel length 16inch.
882 884 888 880 893 883 880 879 880 881 884 882 889 893 895 894 905 901 892 890 903 893 899 893 894 897 890 891 891 880 883 884 875 873 875 869.
Should get 50+shots from 1800 psi with more preload and reduced tp.(http://i1194.photobucket.com/albums/aa378/Froggyroggy/Mobile%20Uploads/IMG_20160123_163845_zpsr83xonhw.jpg) (http://s1194.photobucket.com/user/Froggyroggy/media/Mobile%20Uploads/IMG_20160123_163845_zpsr83xonhw.jpg.html)
(http://i1194.photobucket.com/albums/aa378/Froggyroggy/Mobile%20Uploads/IMG_20160123_163812_zpst3ar4co0.jpg) (http://s1194.photobucket.com/user/Froggyroggy/media/Mobile%20Uploads/IMG_20160123_163812_zpst3ar4co0.jpg.html)
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I pulled apart my 2560 today and swapped it over to the new style one with the internal stop.... Here are the old and new parts....
(http://i378.photobucket.com/albums/oo221/rsterne/22%20PCP/001%201009x1024_zpsmgususb7.jpg) (http://s378.photobucket.com/user/rsterne/media/22%20PCP/001%201009x1024_zpsmgususb7.jpg.html)
I am now using a 10-32 machine screw with a piece of 7/32" OD tubing slid onto it for the guide.... Then you slide on the spring and an aluminum collar that hits the end of the gap adjusting bolt when cocking the gun and compresses the spring.... The stop nut is turned from a piece of 5/16" rod, drilled and tapped 10-32 and tightened against the end of the brass tube.... I start out a bit longer than I need and keep shortening the tube until I can get the gun shooting on the plateau with no gap.... Once I get the right length, I install the stop nut with a drop of blue Loctite, tightened against the end of the tube.... The stop nut has a slot in the end for this purpose.... The gap adjusting nut is drilled just over 5/16" because the stop nut has to slide through it.... The end cap is tapped 7/16"-20NF for the adjusting bolt, and then counterbored just over 7/16" to miss the cocking collar.... At the bottom of the photo is the original SSG I made.... You can see how much shorter the new guide is.... Below is the new SSG assembly, ready for installation....
(http://i378.photobucket.com/albums/oo221/rsterne/22%20PCP/003%20800x282_zpsmo7gen2y.jpg) (http://s378.photobucket.com/user/rsterne/media/22%20PCP/003%20800x282_zpsmo7gen2y.jpg.html)
When the gun is uncocked, the stop nut is recessed about 1/2" inside the gap adjusting bolt, so you can't see it.... Compare this with the one above, where the stop nut and bumper O-ring (no longer required) are outside the gap adjusting bolt.... Below is what the gun now looks like when cocked....
(http://i378.photobucket.com/albums/oo221/rsterne/22%20PCP/006%201024x592_zpsyt2kxlol.jpg) (http://s378.photobucket.com/user/rsterne/media/22%20PCP/006%201024x592_zpsyt2kxlol.jpg.html)
This installation is much cleaner, and there is no way you can pinch your fingers like could happen with the old one.... However, you still have a cocking indicator because the stop nut (the part with the slot) is visible when cocked.... With no gap I had about 985 fps, which I could adjust down to whatever I wanted.... At 1-1/2 turns out the velocity was just over 900 fps and the gun was very quiet.... I ended up about 1 turn out, with a average velocity of 960 fps, the same as I had before.... I might have lost a couple of shots compared to the first SSG, but I have still gained about 40% more shots per fill than without the SSG.... and I no longer have to worry about pinching my fingers and I can wrap my thumb over the wrist of the stock again because is it so much more compact.... The efficiency is around 1.40 FPE/CI....
Bob
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Can see where a longer spring/longer stroke is going to be needed. Just going to need a longer stroke/longer spring/ stronger spring.
Just using the standard stroke with a 2260/2240 type end cap isn’t going to get any real power unless the spring is super-stiff. If I want more power am going to have to make a longer rear end cap, deeper recessed, in order to fit a longer (likely stronger as well) spring in order to increase the stroke.
SSG has potential, although the early results using 2260 length springs/stroke are a little mixed. Have actually gone DOWN in efficiency from the previous tests, but picked up energy per shot. Over all, the efficiency and shot count has increased.
Tested with a pair of 2260 conversions. A .177 version (left) and a .22 version (right). Only 72-73cc's of air, so the shot counts won't be massive:
(http://i157.photobucket.com/albums/t50/ribbonstone/HiPaC/57f2cb70-38dc-48a1-92b7-925ee7de27d5.jpg) (http://s157.photobucket.com/user/ribbonstone/media/HiPaC/57f2cb70-38dc-48a1-92b7-925ee7de27d5.jpg.html)
Simplest SSG version:
(http://i157.photobucket.com/albums/t50/ribbonstone/HiPaC/353e538d-58e6-4b32-8941-0ae4c7f406ff.jpg) (http://s157.photobucket.com/user/ribbonstone/media/HiPaC/353e538d-58e6-4b32-8941-0ae4c7f406ff.jpg.html)
Long bolt, end cap with a hole, shorter/stiffer spring, o-ring, lock nut, and a 2nd lock nut (in this case a kind of wingnut).
Assembled it looks like this:
(http://i157.photobucket.com/albums/t50/ribbonstone/HiPaC/2e82b5a2-6318-4d40-96f1-f883871e9713.jpg) (http://s157.photobucket.com/user/ribbonstone/media/HiPaC/2e82b5a2-6318-4d40-96f1-f883871e9713.jpg.html)
THINK the idea is to keep the spring tension off the valve stem, so that any opening of the valve is just by the inertial of the striker. So as you adjust the lock nuts IN, the spring gets shorter, and there is less and less tension on the striker as it contacts the valve stem. Think of it as a “sling shot” striker.
(http://i157.photobucket.com/albums/t50/ribbonstone/HiPaC/12c7bd26-5d44-4f49-b10a-7ca2e97efc41.jpg) (http://s157.photobucket.com/user/ribbonstone/media/HiPaC/12c7bd26-5d44-4f49-b10a-7ca2e97efc41.jpg.html)
So to adjust it for these tests:
1. Adjusted the lock nuts out.
2. Pulled trigger.
3. Whacked the end of the adjuster with a stick.
4. If the valve opened even a little bit, adjusted the lock nuts "IN” until the valve didn’t open at all.
So this set it to about .052” of striker stroke. More than that, and the valve would (weakly) open when the adjuster was struck.
AM POSITIVE there is more to be gained by adjusting them in small increments.
But as a gross head-to-head test:
Shots with the lock nuts totally out of play (adjusted way-way back):
.177/2260:
9.3gr. WC / 25 shots inside of 4% (from 725-696fps) / 10.4 foot pounds / efficiently of 1.15 FPE/cuin
.22/2260
15.9gr. JSB / 24 shots inside of 4% / 14.2 foot pounds / efficiency of 1.38 FPE/cuin
Everything the same as above, just the SSG adjusted. With the adjuster set as described above:
.177/ 2260
9.3gr. WC / 42 shots inside of 4% / 657 – 631fps / 8.6 foot pounds / efficiency of 1.4 FPE/cuin
.22/2260
15.9gr. JSB / 30 shots inside 4%/ 672-645fps / 15.3 foot pounds /efficiency of 1.58 FPE/cuin
MIXED REVIEW:
BOTH of them dropped their sweet spot from 2100psi to 1800psi. That’s pretty well proof of a lighter striker hit to the valve.
The RANGE of pressure was about the same. Without the SSG adjusted as listed, sweet spot ran about 2000-1000Psi. With the SSG adjusted, sweet spot ran about 1800 – 800psi.
The .177’s energy went down by about 16% and the efficiency went up by 22%...which seems pretty darned close to even to me.
The .22’s energy went up by about 8% AND the efficiency went up by about 15%, which is definitely a “win”.
EXPECTATIONS:
Now likely there will be an adjustment that would get the .177 back in line. It always seems to be those little 1/8th - 1/4th turn adjustments that do the trick. I’d hope for BOTH and increase in energy and at least the same efficiency, but I’ll have to work at it.
Might be that a standard weight 2260/2240 striker would do better than a lighter weight striker. If I got the idea right, it’s about a striker hitting the valve without ANY spring tension, so a heavier (standard weight) striker might be in order. Both of these have been lightened.
Going back to a full sized transfer port would up the air flow. Might detract from shot count, but would increase the energy per shot…have to balance that.
It certainly looks like there is something to be gained here. Likely it is a reduction in the hammer bounce issue that’s increasing the efficiency.
It certainly looks like there is something to be gained here. Likely it is a reduction in the hammer bounce issue that’s increasing the efficiency.
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I pulled apart my 2560 today and swapped it over to the new style one with the internal stop.... Here are the old and new parts....
(http://i378.photobucket.com/albums/oo221/rsterne/22%20PCP/001%201009x1024_zpsmgususb7.jpg) (http://s378.photobucket.com/user/rsterne/media/22%20PCP/001%201009x1024_zpsmgususb7.jpg.html)
Bob
Bob are you still using the 1.75" x 0.040" wire spring for this one?
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That gun has always used a QB spring, in all three versions, original, first SSG, and new SSG....
Bob
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Had some "personal time" in the garage this morning...
(http://i245.photobucket.com/albums/gg76/gippeto_album/IMG_5551_zpschsufqzg.jpg) (http://s245.photobucket.com/user/gippeto_album/media/IMG_5551_zpschsufqzg.jpg.html)
And a bit more time in the garage after supper. :)
Scrounged up enough parts to assemble an otherwise stock-ish 2240. No chrony numbers tonight, but does flush a 14.3 CPHP in a well seasoned 2x4. First test shot had a bit of the usual BRaappp...turned the adjuster bushing out a half turn and....GONE. Crisp snap to it now like I've NEVER heard from a 2240. 8)
Still need to trim the guide rod to length and add a screw driver slot to it...and make a proper pin spanner to adjust the bushing...already scratched the brass turning the bushing with a screwdriver. :(
Curious to see how fast it's actually running...and how many shots per cartridge...tomorrow.
Thanks Bob. 8)
(http://i245.photobucket.com/albums/gg76/gippeto_album/IMG_5554_zpsw8o7sbif.jpg) (http://s245.photobucket.com/user/gippeto_album/media/IMG_5554_zpsw8o7sbif.jpg.html)
(http://i245.photobucket.com/albums/gg76/gippeto_album/IMG_5555_zpsm86jw7h9.jpg) (http://s245.photobucket.com/user/gippeto_album/media/IMG_5555_zpsm86jw7h9.jpg.html)
Al
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anyone do this with a marauder .25?
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anyone do this with a marauder .25?
http://airgunguild.com/index.php/topic,11.0.html (http://airgunguild.com/index.php/topic,11.0.html)
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Hopefully someone gets an instructable video up for those of us with ADD. :o
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Al, I don't have a near-stock 22XX around here, and there was little point doing it to my 1740 or 1750, as they already get over 100 shots per cartridge (at just under 500 fps).... I would not be at all surprised if on a stock 2240 it might double the shot count with basically no loss in power.... I'm REALLY looking forward to your results....
Bob
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Here is a non-protruding method that I put into my .25 Armada. The stock design prevents anything from protruding out the end cap.
(http://www.ar15.com/media/viewFile.html?i=84721)
It may still be holding the spring a little bit long as there is almost no hammer play between the valve and the pre compressed spring.
The spring is from a stock Gen 1 .177 Marauder. The hammer stroke is now at max. I lost a little bit of velocity with this lighter spring, but I now get 30 uniform shots on a 165 BAR (2395 psi) fill. I'm going to turn the velocity up soon. I am also making another slightly improved version using the spring that I took out of
The velocity for the JSB Kings (25.4 gn.) started at 709 ft/s, peaked at 721, and fell back to 708 at 124 BAR (1800 psi). The average velocity was 712 with a sample standard deviation of 3.6. This appears to be an efficiency of about 1.6 ft-lbs E/Cu in. (If I found the right calculator).
The parts for the cable stopping spring guide are two cut down .38 special cases that started to have cracks on the mouth, a bit of 50 pound test Dacron fishing line---four strands, a bit of glue, and a piece of plated brass for the stop in the end cap.
The caps were drilled out and notched, and the line threaded through and secured with a plug and glue. The hammer side has a larger hole to accommodate the adjustment screw. The line wraps around the case on this side as well.
The improved version has 17/64th holes drilled in each case head, notched and the line is secured with JB weld. It is untested as of yet.
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, a bit of 50 pound test Dacron fishing line---four strands, a bit of glue, and a piece of plated brass for the stop in the end cap.
FYI - Dacron line will stretch. Not sure how it will affect the design.
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Little update;
Took some tinkering to get this working sort of right. Initial shot count was no better than stock. Seemed like too much dwell due, I suspected to too much striker mass. Tried it with a hipac and could only manage a decreasing string from 2000psi. Sooo...put the striker on a diet.
(http://i245.photobucket.com/albums/gg76/gippeto_album/IMG_5558_zpsemhp179g.jpg) (http://s245.photobucket.com/user/gippeto_album/media/IMG_5558_zpsemhp179g.jpg.html)
Still too much hit. :roll: Changed to a spring that I thought was WAY too light and got an increasing string with the hipac. Cocking effort is pretty much the same as stock.
Also made the spanner wrench...WAY easier to make adjustments now.
(http://i245.photobucket.com/albums/gg76/gippeto_album/IMG_5561_zpscetlgoml.jpg) (http://s245.photobucket.com/user/gippeto_album/media/IMG_5561_zpscetlgoml.jpg.html)
So back to the 12g carts...not really "tuned", just enough preload to pierce the carts and about a .030" gap. Quieter than before and no cloud of co2....and no braapp. :wink: Zeros are a read error on the chrony.
(http://i245.photobucket.com/albums/gg76/gippeto_album/2240%20ssg%2012g_zpsc5bsf4zf.jpg) (http://s245.photobucket.com/user/gippeto_album/media/2240%20ssg%2012g_zpsc5bsf4zf.jpg.html)
Pretty pleased with these as initial results, will do more tweaking yet....which is the fun part. 8)
Should perhaps note the shots were not stretched out...load, aim, shoot, write it down, repeat.
Al
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, a bit of 50 pound test Dacron fishing line---four strands, a bit of glue, and a piece of plated brass for the stop in the end cap.
FYI - Dacron line will stretch. Not sure how it will affect the design.
True, but if it didn't it could not absorb any energy. Even the steel rods in the devices have to stretch in order to absorb energy. It appears that the Dacron line has a 2% elongation at break. This is .04 for a 2" long string. At 50 pound test, it means that each strand will absorb 2 in-lbs at break.
A spring that has about 10 inch pounds of energy would break the four strands were it not for the significant mass of the hammer. The actual energy the strands have to absorb is going to be a lot less than bringing them to break. The stretch is also going to be significantly less than .04"
However, this may be part of why I don't think I currently have enough of a gap. The efficiency is not bad, though, with what I have. I'm going to play next with the original spring (shorter) and make a flush hammer head.
Oh, the other nice thing about the Dacron line is that it has no appreciable creep. That is it does not get longer over time while under stain.
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, a bit of 50 pound test Dacron fishing line---four strands, a bit of glue, and a piece of plated brass for the stop in the end cap.
FYI - Dacron line will stretch. Not sure how it will affect the design.
True, but if it didn't it could not absorb any energy. Even the steel rods in the devices have to stretch in order to absorb energy. It appears that the Dacron line has a 2% elongation at break. This is .04 for a 2" long string. At 50 pound test, it means that each strand will absorb 2 in-lbs at break.
A spring that has about 10 inch pounds of energy would break the four strands were it not for the significant mass of the hammer. The actual energy the strands have to absorb is going to be a lot less than bringing them to break. The stretch is also going to be significantly less than .04"
However, this may be part of why I don't think I currently have enough of a gap. The efficiency is not bad, though, with what I have. I'm going to play next with the original spring (shorter) and make a flush hammer head.
Oh, the other nice thing about the Dacron line is that it has no appreciable creep. That is it does not get longer over time while under stain.
I wonder how spider wire would work in this application?
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any suggestion about how many gap bettween hammer and valve stem
maybe some one here already got some data abaout some various gap and the efect
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I'm not sure how much 'data' can be presented for this measurement, as there are so many variables depending on each person's other modifications, their desired power level, etc. But generally speaking I think it's safe to say that the smaller the gap the better when the right spring strength and preload are in place for a given tune, as this makes the most use of the spring's energy. Too large a gap and striker impact will be less, resulting in lower power. Of course this can be used to fine tune the velocity... but again, getting into too many variables, and adjusting preload for power then closing the gap to quite small seems a better approach.
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Even the steel rods in the devices have to stretch in order to absorb energy.
Can you explain this? Are you saying the guide rod "stretches" on each shot to absorb the energy from the spring? If so then how are you keeping the gap the same? Wouldn't the gap (between spring and hammer) be getting smaller on each consecutive shot?
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Over time some steels may creep slightly, but I think what was meant was that there's energy being absorbed via elastic elongation of the guide rod, which then returns to its normal length. Very, very slight elongation. Like an incredibly stiff extension spring.
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Even the steel rods in the devices have to stretch in order to absorb energy.
Can you explain this? Are you saying the guide rod "stretches" on each shot to absorb the energy from the spring? If so then how are you keeping the gap the same? Wouldn't the gap (between spring and hammer) be getting smaller on each consecutive shot?
All non brittle materials will stretch or compress depending on the load direction. It may not be much in the case of a steel rod (think in terms of ten thousandths of an inch). But it will spring back to its original length for a given load. It is not a permanent lengthening until you exceed the yield point.
The energy the rod or cable absorbs is the equal to the force times the distance. If the distance of the stretch or compression is very small, the force is quite large. This is why you can break cast iron with a hammer, but it will hold a large static load without breaking.
Cast iron has very little give, which makes it brittle. If you take something very resilient like a rubber band there is a lot of give, and it can absorb more energy with a lower average force.
Steel, string, and all materials act a bit like a rubber band, but on a scale that you cannot see with your eyes.
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I think he means the steel guide rod is stretching elastically (which is true), but it will be well within the yield strength of steel.... Many of the SSG designs use an O-ring to cushion the blow on the stop nut on the rod (which is likely hundreds of "G" without it)....
Spectra (spider wire) has appreciable creep (elongation with load over time).... This is mostly due to its slipperiness, the strands in the line don't stick on each other, allowing the braided line to get longer and thinner as the gaps in it move.... (We used to use Spectra for the sheets on our R/C Model Yachts, which is why I know that)....
The amount of "gap", in theory, can be as small as possible, particularly on the original design where the guide stops and only the hammer keeps going.... I notice a complete elimination of hammer bounce in just 0.020" of gap most of the time.... Less than that, and you are probably in the grey area where the O-ring is compressing and the head of the poppet is too.... With some of the designs, it seems that the gap needs to be a bit larger to complete the transition between preload (bounce) and fully debounced, perhaps as much as 0.040-0.060".... In addition, Travis ran into a bit of a weird characteristic with the bstaley style SSG, where the guide passes through the hammer and it is the end of the guide that opens the valve.... He found that as he increased the gap from zero, the velocity actually increased for a bit before declining again.... We think what is happening there is that since the guide is stationary, back away from the stem, and is picked up by the moving hammer before it hits the valve, it has to have a short distance to accelerate.... and hence the velocity peak at 0.040"-0.050" of gap (on the one Travis was working on, anyway)....
All of my SSG installations are on guns where I know where the plateau is (ie what is the maximum velocity the gun can shoot), so I basically keep increasing the preload until I get to that (or very close) with no gap.... I then increase the gap to drop the velocity onto the knee of the curve, which does two things simultaneously.... It makes sure that the valve is closing well before the pellet reaches half way down the barrel (which is about where the plateau starts).... and the SSG eliminates the hammer bounce.... Tuned this way, the efficiency, and the report, are like an on-off switch.... LOUD AND INEFFICIENT changes to QUIET AND EFFICIENT within about a half turn on the gap adjuster.... BRRAAAPPP to SNAP!....
Bob
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This is a fascinating thread. Pardon my ignorance but can you explain what is meant by 'knee of the curve'? Also, how do you measure the gap.
Steve
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Anyone that has done Bob's "original" SSG on a Marauder, did you remove the stroke screw in the hammer? If you did, what did you replace it with?
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Spectra (spider wire) has appreciable creep (elongation with load over time)....
This is what I meant by "stretch", now Irons was saying that the "steel" rods "stretch too", but they really don't (in the same sense of the word) unless the pressure placed on them is beyond their "yield" strength, right?
So using the "steel" the gap will stay the same, but using the "dacron" (or spectra) the gap will get smaller (with use).......this is what I was providing the FYI for, is this not correct?
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Steve...if you are using the design that has the 3/8 bolt screwing into the endcap, when you turn the bolt in, the oring will move away from the endcap when the spring guide hits the hammer. If you mark one of the flats of the bolt you could measure the distance from the endcap and then turn the bolt out (to start creating a gap) 1 flat or half a turn and measure the distance between the endcap and bolt and adjust accordingly.
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Makes sense. Thanks,.
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Pardon my ignorance but can you explain what is meant by 'knee of the curve'?
Bob has written extensively on the subject, you can find references to the 'knee' in just about all his posts on airgun tuning. It's that part of the measured shot string where velocity peaks. Just after that peak is just 'below the knee', and that's the most efficient part of a given tune in terms of air use for a given power setting. Where that knee sits for a given airgun will vary depending on other elements of the tune. So it's up to you to do chrony testing and chart your results and determine where your knee is for that setup, then in applying that to the SSG one has a number to look for on the chrony while also getting the gap just right.
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really getting up to 50 shots in a .25 m rod with this mod? Need to get a parts list and install one of these when I tune up in the spring, sounds amazing
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Thanks Gerard. I was assuming it was something like that.
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Steve, there is some confusion about the "knee" of the curve, which occurs at any constant pressure (eg. a regulated gun), and the "peak" of the curve for an unregulated PCP.... Read these two threads to understand the difference....
Regulated.... http://www.gatewaytoairguns.org/GTA/index.php?topic=74919. (http://www.gatewaytoairguns.org/GTA/index.php?topic=74919.)
Unregulated.... http://www.gatewaytoairguns.org/GTA/index.php?topic=91915. (http://www.gatewaytoairguns.org/GTA/index.php?topic=91915.)
When at constant pressure, increasing the hammer spring preload will increase the velocity (the "downslope") only up to a point.... Eventually the valve will be open so long that it is still open when the pellet leaves the muzzle, at which point, no amount of preload can add any velocity.... but it will still add dwell to the valve, wasting air.... That region is the "plateau".... Where the plateau transitions into the downslope, as you reduce hammer spring preload, is what I call the "knee" of the curve.... It is where you tune a regulated PCP (or at any given constant pressure) to have the best balance between power and efficiency....
In an unregulated PCP, as the pressure changes, you have a whole bunch of "knees" one for each pressure.... but if you look at your fill pressure (the highest pressure you use), you will find the same plateau/knee/downslope as with a regulated PCP....That represents the absolute maximum velocity you can get with that PCP with the combination of porting, barrel length, pellet, and pressure you have.... If you tune just below the knee of that curve, as the pressure drops, the velocity will increase, the way it is supposed to in an unregulated PCP.... How far below the knee you go, will determine how much the velocity increases, and so the ES of your string....
HTH's.... Bob
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Thanks for the link to that thread. Helps a lot! :). On your internal SSG, it seems that the preload is NOT adjustable once you get the length of the guide tube set? It seems like you'd want to be able to adjust the preload depending on what you are doing with the gun on a given day. Am I missing something? I have a Marauder in 25 and will likely start building one of these soon.
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Steve, I have enough airguns that I set each one up for a specific job, including a specific pellet at a particular velocity.... so I set the preload to accommodate what I need (ie touching the plateau for that pellet).... Then I use the gap adjuster to fine tune the velocity.... You can back it off a long ways in velocity without much movement, BTW.... it is very sensitive to the amount of gap....
If you wanted to be able to adjust the preload on the internal guide, you would need a locknut arrangement, or something like a NyLoc brake in the stop nut.... with the front of the stop nut counterbored for the guide tube to have end play inside.... It's not as easily adjustable as the original SSG, but a lot cleaner and shorter, and won't pinch your fingers....
Bob
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I should have asked this in my prior post as well. On the Marauder, you can adjust the striker length to shorten or lengthen the hammer throw. With the SSG, is the striker just flush with the hammer face?
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Anyone that has done Bob's "original" SSG on a Marauder, did you remove the stroke screw in the hammer? If you did, what did you replace it with?
Anyone ?
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I should have asked this in my prior post as well. On the Marauder, you can adjust the striker length to shorten or lengthen the hammer throw. With the SSG, is the striker just flush with the hammer face?
My SSG devices are being used on pretuned regulated M-rod actions where FULL HAMMER stroke was already in use. Applying the SSG did not change this.
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I think you will find that most knowledgeable tuners max. out the hammer stroke in the MRod, even replacing the movable striker with a recessed on made from a ground off setscrew or similar to increase the stroke beyond stock....
Bob
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Im getting tired of agreeing with BOB LOL. But hes correct because the Mrod has a very short hammer stroke and therefore limited hammer energy. The SSG is a great device because you use it at full stroke minus 40 thou. + or - for given speed needed for given fpe requirements.
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Travis, have you found a good spring, length, preload and gap as a starting point for the Synrod(25)? 950ish fps?
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I have with a WAR valve in place. All the parts are on order for the first production run. I have sent two rifles off to their new homes with SSG in place and the customers have been super happy.
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Ah...but not sharing? :) I also have the WAR and NBH in mine. Looking to make up my own SSG but was hoping to get specs. I'm leaning toward the more recent version reported that is all internal (floating). Looking forward to seeing what you've achieved with SSG in the M/Srod.
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Steve, I think Travis is selling the SSGs for the MRod.... I can understand him not being specific about parts....
Bob
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Well, my Dacron cable failed. It suffered from abrasion due to rubbing on the exposed hammer adjustment pin in the Armada. I need to get more clearance and perhaps a protective sheath on it before continuing with that design.
I have now made an SSG that follows what I originally designed with a page from rsterne, and it does not protrude past the end cap. I put in a 1/4--28 bolt with the head cut off and filed flush with the hammer face. A e-clip groove holds the spring captive well inside the spring guide. There is now a bit of clearance with the spring compressed.
First impressions (I've not yet shot any strings), is that the cocking effort is a bit lighter and a whole lot smoother.
Here is a cut-away view of what I built.
(http://www.ar15.com/media/viewFile.html?i=84775)
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Looks nice, David.... I'm not surprised the cable failed.... Good Luck with the new one....
Bob
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Bob.....can't blame a guy fer tryin! :) Travis makes good stuff...I'm anxious to get a hold of one.
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Description: .25 marauder stock reworked valve with SSG .187 barrel port
Notes 1: 2800-1800psi
Notes 2:
Distance to Chrono(FT): 1.00
Ballistic Coefficient: 1.000
Bullet Weight(gr): 25.40
Temp: N/A °F
BP: N/A inHg
# FPS FT-LBS PF
23 895 45.19 22.73
22 889 44.58 22.58
21 891 44.78 22.63
20 890 44.68 22.61
19 916 47.33 23.27
18 891 44.78 22.63
17 906 46.30 23.01
16 908 46.51 23.06
15 908 46.51 23.06
14 912 46.92 23.16
13 912 46.92 23.16
12 903 46.00 22.94
11 903 46.00 22.94
10 910 46.71 23.11
9 895 45.19 22.73
8 912 46.92 23.16
7 898 45.49 22.81
6 887 44.38 22.53
5 909 46.61 23.09
4 888 44.48 22.56
3 883 43.98 22.43
2 900 45.69 22.86
1 903 46.00 22.94
Average: 900.4 FPS
SD: 9.8 FPS
Min: 883 FPS
Max: 916 FPS
Spread: 33 FPS
Shot/sec: 0.1
True MV: 900 FPS
Group Size (in): 0.00
Sent from my iPhone
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Opened up the stock valve and barrel port then added the SSG, tuned and got around 28 shots but My crono has only 1 working IR light so I got miss reads I deleated the miss reads and the above string is whats left of string. several first shots miss read so string starts high and looks like it has no curve but it does LOL. SSG are being made now and will be on website shortly, I will also be offering a SSG install and tune all in one for big savings.
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One “nay” for the cheap experimenters who make simple SSG’s.
If the spring can kink up, then it can act as a striker limiter. Idea here is that the striker is “free flight” at the end of the stroke. If the spring binds inside the striker, then the adjustment deosn’t let the spring “fly free” and acts as a terminal stroke adjustment.
(One testis to grab onto the lock nuts of the SSG, pull back, and if it moves the stricker back and cocks the gun, the spring is binding inside the striker.)
Use a guide that is large enough to exclude spring kinking…but no so large that it binds the spring….and you should be good.
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I agree 100%.... I mentioned using as large a guide as possible earlier.... thank you for confirming that....
Bob
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One “nay” for the cheap experimenters who make simple SSG’s.
If the spring can kink up, then it can act as a striker limiter. Idea here is that the striker is “free flight” at the end of the stroke. If the spring binds inside the striker, then the adjustment deosn’t let the spring “fly free” and acts as a terminal stroke adjustment.
(One testis to grab onto the lock nuts of the SSG, pull back, and if it moves the stricker back and cocks the gun, the spring is binding inside the striker.)
Use a guide that is large enough to exclude spring kinking…but no so large that it binds the spring….and you should be good.
LOL...on the only SSG currently running, you will need bionic fingers to pull the spring guide back by hand. The pellet shooter OTOH, can probably deal with lots less spring. That one is getting a floating SSG so, nevermind...:)
cheers,
Douglas
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Thats 100% a fact
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http://airgunguild.com/index.php/topic,11.30.html (http://airgunguild.com/index.php/topic,11.30.html) Ready for the Marauder Rifle platforms now.
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I'll ne ordering one of those before I order the mrod!
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Description: .25 marauder stock reworked valve with SSG .187 barrel port
Notes 1: 2800-1800psi
Notes 2:
Distance to Chrono(FT): 1.00
Ballistic Coefficient: 1.000
Bullet Weight(gr): 25.40
Temp: N/A °F
BP: N/A inHg
# FPS FT-LBS PF
23 895 45.19 22.73
22 889 44.58 22.58
21 891 44.78 22.63
20 890 44.68 22.61
19 916 47.33 23.27
18 891 44.78 22.63
17 906 46.30 23.01
16 908 46.51 23.06
15 908 46.51 23.06
14 912 46.92 23.16
13 912 46.92 23.16
12 903 46.00 22.94
11 903 46.00 22.94
10 910 46.71 23.11
9 895 45.19 22.73
8 912 46.92 23.16
7 898 45.49 22.81
6 887 44.38 22.53
5 909 46.61 23.09
4 888 44.48 22.56
3 883 43.98 22.43
2 900 45.69 22.86
1 903 46.00 22.94
Average: 900.4 FPS
SD: 9.8 FPS
Min: 883 FPS
Max: 916 FPS
Spread: 33 FPS
Shot/sec: 0.1
True MV: 900 FPS
Group Size (in): 0.00
Sent from my iPhone
It may be the deleted shots skewing the numbers but this looks a bit strange...
you have a 1% stddev and 3% spread but the numbers are all over the place within the string.
Is there an explanation for this?
Are others seeing this with their SSG's?
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I certainly wouldnt say its all over the place but the 5 deleted shots would smooth it out a lot. My new light kit will be here friday so I will be able to get strings again without drop outs.
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They are tight 1% stddev and 3% spread - but a "classic" string does not tend to jump up and down the whole spread within the group.
This almost looks like a regulated string with a wider than normal (for regulated) spread...
I thought regulated spreads tended to have a 1% spread or so...
So the SSG is SIMULATING a regulator????
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Description: war valve and SSG.25
Notes 1:
Notes 2:
Distance to Chrono(FT): 1.00
Ballistic Coefficient: 1.000
Bullet Weight(gr): 25.40
Temp: N/A °F
BP: N/A inHg
# FPS FT-LBS PF
27 880 43.68 22.35
26 883 43.98 22.43
25 889 44.58 22.58
24 892 44.88 22.66
23 897 45.39 22.78
22 900 45.69 22.86
21 905 46.20 22.99
20 909 46.61 23.09
19 908 46.51 23.06
18 912 46.92 23.16
17 914 47.12 23.22
16 919 47.64 23.34
15 924 48.16 23.47
14 921 47.85 23.39
13 920 47.74 23.37
12 925 48.27 23.50
11 926 48.37 23.52
10 914 47.12 23.22
9 913 47.02 23.19
8 911 46.82 23.14
7 886 44.28 22.50
6 897 45.39 22.78
5 893 44.98 22.68
4 888 44.48 22.56
3 895 45.19 22.73
2 889 44.58 22.58
1 899 45.59 22.83
Average: 904.0 FPS
SD: 14.0 FPS
Min: 880 FPS
Max: 926 FPS
Spread: 46 FPS
Shot/sec: 0.1
True MV: 904 FPS
Group Size (in): 0.00
Sent from my iPhone
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Last string before crono light problem reared its ugly head. Its more the product of the valve being pushed to far or over dwelled. I need to open the seat area of the stock valve to mellow out the curve and dwell the valve less.
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so that was probably an artifact of the chrono light issue.
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Part missing numbers and over dwell of stock valve. I only opened up the transfer port. Seat needs opened up.
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Guess I'm confused. Is the hammer spring still used or is the hammer spring on the ssg? Wondering before I order a 10lb hammer spring.
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It uses its own spring not a marauder type spring. And its all internal no rod comes out the back
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Ready for the Marauder Rifle platforms now.
What I don't completely understand is why you faced off the back of the end cap. If you have a good mill set-up the set-screw hole could be counterbored and tapped just as easily. (Conceal it on the bottom if practical.) If one needs a bigger opening or the ability to put the adjustment screw in from the back end, the end cap could be bored on a lathe just as easily as facing. Plus, it would have a better finished look to it as you wouldn't have as much of a fresh machined surface thus preserving more of the original anondized aluminum.
I like the fact that nothing protrudes beyond the end cap. It means that the thing can be put into an Armada that has enclosed stock.
If these are pictures of the final product and not experimental things whipped up on the spur of the moment, you should consider getting better tooling and working on surface finish. As a machinist, I'd be ashamed of anything that went to a customer looking like this. For experimental stuff, however, it looks just fine.
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I milled off the back so you can change springs without taking gun apart!!! Nice right! I would have them anodized but with such small numbers it would be real expensive. Thats the prototype ive been playing with the customer version will be much nicer. Ill make up a new one tomorrow. They will come with 2 springs for low to mid and mid to high power tunes.
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What are the differences between the MRod and PRod versions? dia only?
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oldpro,
Thanks for alleviating my finish concerns. However, if you were to bore out the back end, couldn't one replace springs anyway. You just need clearance for a socket wrench (perhaps a deep socket) and a screw driver. You might consider providing tools to make adjustments or swap springs.
I think something like a deep socket with a t-handle or spanner holes or slots, and a screw driver would allow one to do any assembly or repairs.
The reason I am saying this is those that have guns, more often than not, want to see new things as pristine as possible. The more your products look that way will go a lot toward sales. Also, tools that come with the thing are also seen as an asset.
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spring tensions and length etc. Much the same in how they work.
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Ill try that tomorrow It sounds like a doable idea. Infact sounds like a real good idea.
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Good.
BTW, that is the thing I tend to be good at---finding the mistakes or improvements that others overlook.
Now finding my own mistakes on the other hand . . . .
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Nope wont work. You cant hold rod and turn spring preload nut no matter how you try i knew there was a reason i did it my way LOL. Ill look for another way though. where theres a will theres a way right.
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Mill six flats on the screw instead of the screwdriver slot.
And, add a thread relief so that the nut will disengage the threads before it hits the nut/screw driver.
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The problem is the nut and spring barely fit threw the hole and ive used the smallest spring with enough coils and tension that will work going threw said hole. I can make a long tension adjuster that fits all the way down thats the only way it could work but it may be a viable option, Tomorrows another day.
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already try to make SSG on my PCP
and the result was so amazing
absolutly zero hammer bounce
i want to add some video but still cant add an external link...
*ttps://www.youtube.com/watch?v=zUoySVHh4sM
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Long tensioner wont work either it wont allow you to adjust the rod gap. I guess im back to where I was already but im ok with that. I could build a full blown unit with externall adjusting knurled knob and preload knob but then we would have to double the price at least and I want this to cost under $100 max. I think its fine the way it is the more I look at it, its easy to adjust and easy to make spring changes and will be well under $100.
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oldpro,
Bore the back end of the end cap out larger so that you can remove the gap adjusting screw. Once that is removed, then you should be able to access the nut, and then internally through the nut driver the screw.
In the worst case, you might need to use a larger diameter gap adjusting screw to allow clearance for the socket wrench.
But, another weird idea occurred to me just now. What about making the gap adjusting screw have a six sided recess that holds the nut. Then, you just wind in the spring adjustment screw until it clears the threads. Loosen the gap adjustment retaining screw. Then remove the gap screw along with the nut and spring (hold parts vertically).
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Can you "round" off the flat a touch and cold blue it? (does cold blue work on aluminum?)
That way it just looks shorter....
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the gap adjuster is also the guide for the rod. none of those ideas will work. I wish they would. I would have to completely remake it and fab all the parts in shop the price would go threw the roof.
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Heres pics of SSG on gun and if I simply put a black decal on flat then it will blend well. And I wont have to raise price or change how very easy it is to adjust and and do spring changes,
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oldpro,
What I am calling the gap adjusting screw is the one in the end cap i.e. 1/2--20 that is retained by the diagonal screw.
Simple three sided mill cuts on that screw would be enough to retain the primary adjustment screw (the one on the spring guide) enough to hold it in place against the Nyloc nut while one turns the screw in or out. No need to remove it for regular adjustments.
If one wants to replace the spring, then they first wind the adjustment spring in until it clears the threads. Next they back out the retaining screw. And finally wind out the gap adjustment screw.
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oldpro,
What I am calling the gap adjusting screw is the one in the end cap i.e. 1/2--20 that is retained by the diagonal screw.
Simple three sided mill cuts on that screw would be enough to retain the primary adjustment screw (the one on the spring guide) enough to hold it in place against the Nyloc nut while one turns the screw in or out. No need to remove it for regular adjustments.
If one wants to replace the spring, then they first wind the adjustment spring in until it clears the threads. Next they back out the retaining screw. And finally wind out the gap adjustment screw.
MAKE ONE and share it .... Pictures of actual working parts are KING !
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I understand what your saying but it doesnt work like you think, I will have to take it apart and lay it out so you can see what I mean. It doesnt work like Bobs design in function but does as a unit.
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So, it is not as simple as a fixed rod going through the hammer where the hammer strikes the rod---the spring being compressed by the hammer while the adjustment nut is retained by the gap adjustment screw in the end cap? For, that is what it looks like in the photos.
If it is more complicated than that, then my attention is peaked. ;D
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No thats it but I dont understand how your idea is going to make it adjustable still. Thats why I said that. Post a drawing or cad file or make one because I do not understand what your saying I guess. Im not trying to dismiss your idea I just dont see it in my head please post a drawing etc. and I will have a look.
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A GREEN Wasp sticker!
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Upon looking at realistic dimensions a deep socket will not be required.
This is a cross sectional view with an end view of what I think the end cap should look like with the phantom lines showing what the end cap was originally.
(http://www.ar15.com/media/viewFile.html?i=84781)
With the gap adjustment screw removed, one should get a socket wrench on to the adjustment nut with the clearance provided with the counter-bore. The gun may have to be cocked. Then the screw can be rotated in to clear the threads. That should relieve the spring for removal.
On the second idea, imagine if the gap adjustment screw had provisions to hold the nut in place, i.e. flats. One could, conceivably, make tension adjustments just by turning the screw. There would be no need to remove the gap screw. Also, with this one could wind the screw in until it was clear of the nut. Upon removing the gap screw, then the spring would be free along with the adjusting nut.
ETA: The retaining flats would be at the right hand side of the magenta gap adjusting screw.
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How is this better? I still dont see the advantage? This will make moving that nylock nut very difficult and I still have raw aluminum sides that are unfinished.
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I guess you now see the original material that you retain with a counter-bore rather than facing it all off.
ETA: This was being posted before your edit. However, I think it still applies.
The original anodized material is going to look a lot better than "bright" machined aluminum. I also suggest blackening the bright aluminum with either Birchwood Casey's Aluminum Black or black paint.
I agree that the added expense of having the parts anodized (especially re-anodized) is not worth it. Plus, if you are buying parts from Crosman, the re-anodizing process will remove material making the parts smaller.
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I guess you could put a plug over the end with a small vent hole, I can try it out if it is a hassle I can just face it off. Ill try it.
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One thing I am not sure is being addressed by the "flats on the gap adjusting screw to hold the preload adjusting nut".... The preload adjusting nut, which also acts as a stop to prevent the spring from moving aft when you cock the gun.... moves FORWARD by the amount of the gap PLUS the amount the valve opens.... Any flats would have to be long enough to prevent the nut from rotating even a fraction and hanging up, which could conceivably hold the valve open.... Just something to think about and allow for if you haven't already....
Bob
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What you are saving is the visual surface that would be removed by facing rather than counterboring.
It may not seem to be much from a manufacturing standpoint, but from the customer viewpoint it can make a big difference.
The disadvantage from an assembler's view is that you now require a socket with a handle that does not cover up the hole down the center. This is where specialized tools become an advantage.
However, there is the nicety of have the ability to work on stuff with no tools at all. Any tools that are needed are also a part of the design. But those kinds of thing require thinking from the first drawing board, not when you are trying to improve on an existing design.
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There are no flats on mine. The visual surface is flat and could easily be covered with a black vinyl sticker.
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Bob,
You are right, in that the flats need to be at least as long as the height of the nut flats. Beyond that, when you adjust the spring tension, you should also be adjusting the gap to maintain it at about the same amount. As, I would think, that that is the primary advantage with this design.
My thoughts were to the niceties for the user, rather than for the maker. But, the user would need to be aware of any pitfalls like what you described.
oldpro,
The flats would be on the inside of the gap adjusting screw to keep the nut from rotating while one turns the screw. It would be three cuts with a endmill at 120 degrees for each pass. (More passes might be required as the depth of cut may exceed the limits of what the endmill can handle with a single pass.)
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The more I think about it the more I want to keep it just like it is, I can easily adjust it and dont need special tools and spring changes are a breeze and having to reach into a counter bore and try to compress the spring and start a nylock nut would drive anyone crazy. I put a lot of thought into this and Im convinced its the way to go. Some may not like it but I cant please everyone. I do appreciate the ideas I sincerely do.
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http://www.rustoleum.com/product-catalog/consumer-brands/professional/aluminum-primer-spray (http://www.rustoleum.com/product-catalog/consumer-brands/professional/aluminum-primer-spray) Found this etch primer im going to try it out with some matching black paint
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If you're going with Rustoleum, I'd suggest their Epoxy Appliance Paint line. Unfortunately only available in white, black, and silver, but I've had some excellent results with the black. No rattle can I've tried has ever fully hardened with air drying. All remain easy to scratch. But back in the eary 1980's when I raced BMX bikes I discovered that spray enamels could be baked to harden them properly, which did wonders for scratched up brake calipers and levers and pedals and such. Just prep the surface, cleaning with solvent, then a few light coats per the instructions, then bake at about 200F for half an hour, then up to 350F for another 10 to 15 minutes, watching carefully to make sure things don't get smokey. I got such durable results that I've used the technique on a number of other things since.
More recently when painting a few airgun parts I've made I've found the Rustoleum epoxy paint to be even tougher. Amazing stuff really. I smooth everything, wipe down with rubbing alcohol, heat with a hot air gun until about coffee hot, then do one very light coat and wait a minute. Another bit of heat from the air gun then another light coat. Too much and this paint sags badly, but hey, that same property means it flows out very evenly. Then after about 10 minutes to get really sticky and get rid of some of the solvent in the paint I bake, starting at about 200F to 225F, then moving it up to 350F for the last 10 minutes. Let it cool for at least half an hour before handling as it's still hardening while cooling. If there's any dust motes stuck in it leaving little bumps I'll smooth with 0000 steel wool, maybe 600grit paper if necessary, then re-spray lightly and re-bake. The result is a slightly plastic-looking finish, but it's a nice rich black tending towards deep brown in strong light. After a few days to fully cure the stuff is amazingly scuff resistant, and if you've done your surface prep well there should be no tendency to chip. I'm sure some of the enamels will work just fine too, but just saying this product is my fave for now.
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Thank You Gerard ill try that.
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I have been following this since the first post the end of December on a couple sites and it is fascinating. I made one like Bob's original design but I can't get power back with my current springs. Does anyone have a design for a disco .22 that has been tested and is using a specific spring?
I want to get 800-850 fps with jsb 15.89 and would love to be able to order what I need to finish this.
I am hoping that ideas and information continue to flow without people keeping it to themselves because they hope to produce them and profit from it.
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McMaster 24CP .047x5/16x2.5
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Thanks Oldpro. I've talked to people that are excited to make and test their own SSG, either because they love to tinker or can't afford to buy one...and other that just want a drop in solution because they don't have the tools or skill or time.
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That sounds about right mooseslayer.
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Oldpro,
The as-built drawings are the only ones that really matter. ;)
Nice job.
Lloyd
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OldPro, Did you shave the back of the end cap so the original spring tension screw can exit out the back? Is that screw now the 'gap setting' screw?
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Yes and Yes
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Sign me up for one. My un-modded SynRod 25 is just sitting here waiting for one. I would try to fabricate one if I had the tools.
Thanks everyone for the R&D that has gone into this. I have been watching and learning a ton... knee curves, etc.
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Thanks OldPro...that was brilliant! :)
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You have to machine off the spring adjuster guide section and leave only the threaded portion or you wont have enough room for the spring and rod.
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I see they finally "woke up" over on the Yellow and are now talking about the SSG.... Steve in NC has developed his own version for the MRod, looks very similar to the one Travis came up with (although it may have the guide fixed to the hammer).... In his words "the race to bring one to market is on".... *LOL*.... It seems there is some surprise (once again) that I released the idea rather than try and market it.... They just don't seem to get it that ideas like this should be shared.... but are glad when they are.... Not so sure Daystate will be very happy about Steve calling it a "Sling Shot Debounce Device" though, since they use that name for their Slingshot Hammer....
Bob
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Shall we call it Bob's SSG then?
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Many are already.... just don't call me too late for dinner.... *LOL*.... I never like to claim to have invented anything, because it often turns out that it was done decades ago, and I fully expected that.... So far, although some comparisons have been made, nobody has come along with something predating the SSG that uses a preloaded spring and gap to eliminate hammer bounce.... so maybe, just maybe it really is "mine"....
Bob
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Mines being listed as THe Sterne SSG. credit where credit is due and Steves a little late I have them in stock LOL
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Way to go, Travis !!!
Bob
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Mines being listed as THe Sterne SSG. credit where credit is due and Steves a little late I have them in stock LOL
I didn't see them on the webpage. How much are you selling them for?
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Ill have pics ,prices etc. up today sometime, price will be $95 as a drop in unit ready to fly with two springs and instructions plus my personal line for help tuning etc. I will give $20 credit back if you send back your stock parts. (hammer, spring guide, rear cap). You can call now and order if you cant wait till pics and payment info is up.
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Has anyone heard of an SSG being tested on a Bulldog? Could one be fitted onto a Bulldog?
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Ive tuned a dozen or more bull dogs and they have very light hammers and very heavy springs and get almost no hammer bounce plus with limited shot count it all spells not worth the effort or NWTE as we say here at WAR.
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Mines being listed as THe Sterne SSG. credit where credit is due and Steves a little late I have them in stock LOL
Well done! Glad to see you folks can make this happen. I will bet heavily there are no null results where this device for some reason fails to perform...or makes the cocking stroke crunchy, or...heh-heh-heh
Now do please don't let it get in the way of prepping my Wasp Major...:)
cheers,
Douglas
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Bob is this the one you seen on the Yellow? Do you see all the flaws and problems I do!!!! http://www.network54.com/Forum/79574/message/1454028263/DIY+Marauder+Rifle+%28both+generations%29+FreeFlight+Hammer+Debounce+Kit+-+%2430.45+shipped (http://www.network54.com/Forum/79574/message/1454028263/DIY+Marauder+Rifle+%28both+generations%29+FreeFlight+Hammer+Debounce+Kit+-+%2430.45+shipped)
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Yeah, I see a few things I'm not keen on.... undersized guide allowing the spring to kink.... the nylon part may be able to get out of line with the top end of the guide.... no brake shown for the gap adjusting sleeve.... I assume all you get are the 5 numbered parts and a drawing of how to assemble it with your hammer and spring....
Bob
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Darn Capitalists !! ..... teach a man to fish and you never ever get asked to go fishing again.
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And you have to take gun apart to make spring changes. Spring is too big in bore and riding on hammer wall etc etc. You get what you pay fore. I never post anything on the yellow because the whole site is so hard to follow so I just dont. Id like to show people who think there getting a Rstern SSG how its suppose to be done. THE WRIGHT WAY. Someone post this thread there before people waste their $30
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Another issue is that by using the stock MRod spring, the gun will end up being harder to cock.... so that advantage of a properly designed and set up SSG will have disappeared.... I just hope that in the rush to make a buck it doesn't give the concept a bad reputation.... That could easily happen if problems arise, not saying that they will.... Interestingly, this is the first time I have come up with a marketable idea, published it in the public realm, and had it commercialized, without being asked permission first, like Travis did.... All those interested in my Bob's Boattails, the Millennium Pumper, and a few other things I came up with, have at least asked if I objected to them being produced for sale.... They all, of course, received immediate permission without compensation.... because that was always my intention.... but they did ask.... My only requirement has always been only recognition for the concept or design, as the case may be....
Bob
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Seems inevitable that in any such explosion of interest in a new mod there will be successes and failures and everything in between, largely among experimenters (myself included) but of course among commercial efforts as well. The one Steve in NC is marketing so cheaply looks like a first or second attempt, a bit cobbled together and too fussy, subject to further experimentation. The massive gap between guide rod and spring does seem a bit absurd... why not just use a bigger rod, or use a filler piece like some delrin which would double as a lower friction guide? But people will buy what appeals to them, make their mistakes. There will always be those who insist on buying the cheapest possible version of anything. It's their money. I don't think it'll have much of an effect on the SSG in terms of impact on hobbyists generally. It's a heck of an innovation and this mega-thread among others will no doubt perpetuate the properly constructed versions widely, with echoes carrying on for years around many international forums.
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People would be far better off making there own then putting that contraption in their gun, there is enough info here to do so. Shameful really.
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Isn't competition great! :) Looks to have a few areas that can be easily improved. I'm sure we will see many of these initial designs evolve over the next year. Everyone benefits. :)
Bob made his remarkable work "open source", just like all the technical knowledge he has shared here over the years. IMHO, those making them for profit should be "paying it forward" to keep that spirit alive. Donations to GTA is the first thing that popped in my head. ie make sure that others ideas can be shared in the future. Just my thoughts.
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Couldnt agree more. You have too give too receive. My problem with his model isnt the competition its the fact people are going to buy it and have problems and not live up to what Bob had intended then it will get a bad rap and make it hard for people like myself who work hard at doing it right to make a few dollars. Then the people who Im building them for(people who want a drop in device thats trouble free, or the guy who simply doesnt have time to source parts and experiment) wont get to take advantage of a fantastic device.
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It will take much more than one bad implementation to kill this idea. ;) Maybe it is a good thing he didn't use Bob's name on it.
IMO: The "real" crime will be when some mfg start using it. Very unlikely that there will be any "pay it forward" from them. :(
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I offered to pay Bob he turned me down, Bob is a good man thats for sure and thats why I asked him before I even attempted to build one. I may use it in the Flex if it pans out but im not sure yet if it would help it already has a similar set up on board. Fuzzy if he sells enough of them it will put a black eye on the SSG I still have to explain to people to this day our NBH isnt the same thing as the AOA device.
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I offered to pay Bob he turned me down, Bob is a good man thats for sure and thats why I asked him before I even attempted to build one. I may use it in the Flex if it pans out but im not sure yet if it would help it already has a similar set up on board. Fuzzy if he sells enough of them it will put a black eye on the SSG I still have to explain to people to this day our NBH isnt the same thing as the AOA device.
Yep, Bob is a real altruist within the airgun community with out a doubt.
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I have to be somewhat
glad flattered, in that Steve has used my concept for his design. However, he has made a couple of modifications by using a "Chicago Nut" type of striker instead of a 1/4--28 threaded rod. His design allows for adjustment without changing the hammer starting point on cocking, thus giving the full cocking distance to compress the spring.
However, I agree with Bob and Old Pro, that there needs to be a better fitting spring guide. This may be something that he omitted in his drawing but is incorporated in the final product. That remains to be seen.
On another note, I found that a 25-20 cartridge case fits the .25 Armada OEM spring quite well. I found that the .177 Gen 1 Marauder spring is too light on full travel. I have pre-compressed it more with some spacers, but that requires more of a gap to allow it to cock (without modifying the end cap to allow for a shorter screw).
I'm working on a system to use the larger wire .25 Armada spring. The .25--20 case seems to be a good guide for this. I'll see how it works before posting the details.
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David have you actually ever built and tested one because if this is your design you should completely rethink it. Im not trying to be mean but it has so many flaws. I made 10 different models then 5 different renditions of final model. Nothing beats actual builds and crono time and that goes with any devise or experiment.
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Travis, just because one iteration of a concept could be improved is no reason to throw out that version of the SSG.... My summary of David's concept can be seen summarized in Reply # 356 on page 18.... although his post about it is even further back....
Bob
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Its the implementation of YOUR design not the design thats the problem. Im not saying throw it out but make it right before you take credit for it and SELL it to the public. Did either men ask you for a simple ok? I doubt it. Bob I finally get to disagree with you haha!
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I seriously doubt that Steve asked David's blessing either.... David has been contributing to this thread for quite a while (Reply #266, page 14), and I have no problem with his input, in fact my latest version is based on his concept but with a loose guide instead of it fastened into the hammer.... Your design is quite similar to the one that bstaley proposed, so they are all related....
Bob
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After looking back threw the pics and thread David (I like Irons)I owe you and apology it was steves attempt at your design that got me flustered I am sorry It read in your post like you were partners with Steve and the design hes selling! It just bugs me when I see people turn out stuff like this to the public when I work my butt off trying to get it right. Again David sorry. dangit Bob I guess I didnt get to disagree with you aaarrrgggghhhh...Humbled
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Easy to get emotional when you are close to something.... I do it all the time.... I find that after the first few hundred helpings of humble pie, you actually acquire a taste for it.... *LOL*.... No harm, no foul, as far as I'm concerned....
Bob
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Yep I read the post wrong and thats on me. I had it in my head he was partners with Steve but its now obvious Steve just used his idea and poorly. :-[
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Well ... as designs get hashed out, tried & tossed for another in the on going search for the ideal SSG design ... The original idea which keeps all the spring / stop rod parts independent of the hammer has the most consistent hammer strike of all IMO. No secondary vibrations from the hammer spring, No cant or bind issues when done correctly. Outside of the stop rod protruding out when cocked is has no faults that I have seen.
4 personal PCP's done with the same style ( Shared early in thread ) having all operate flawless with very tight velocity spread.
Cool to see the innovation, but don't find myself changing out whats already done 8) K.I.S.S. works
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So, did anyone make a parts list for the marauder yet? thanks
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Fuzzy if he sells enough of them it will put a black eye on the SSG I still have to explain to people to this day our NBH isnt the same thing as the AOA device.
Travis, understand, but given you are a seller of a similar device it can be perceived by people who don't know you, that you could be worried more about the impact to your sales, then the purity to Bob's design. It is easy to take it personal, but recommend just letting it go. Speaking of the NBH, I suspect your SSG will be a NBH killer. Lower cost, easier to adjust, and probably better longevity. There maybe a niche still for the NBH in certain applications, though. The better mousetrap replaces the old one.
As with any device and implementation, there will be drawbacks and benefits to each. While a more thought out design, such as yours, will be easier to adjust, have more flexibility, more consistent shots, etc, there is no proof at this point that his implementation does not work. It certainly appears that he trying to "jump the gun" ;) to be one of the 1st sellers, but he is also constrained by his designated price point. While he has posted pricing, also mentions still in testing. If it is a dud, people will report it as such. Just like as reports will come in on your implementation, indicating how easy it is to adjust, etc. The marketplace will always sort it out. Just like LDC's and other devices for our guns, there will be all sorts of price ranges and tradeoffs associated with each.
FWIW: the fact that he did not ask Bob's permission, has a more direct impact on my non-purchase decision, than the design limitations. ;)
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Well ... as designs get hashed out, tried & tossed for another in the on going search for the ideal SSG design ... The original idea which keeps all the spring / stop rod parts independent of the hammer has the most consistent hammer strike of all IMO. No secondary vibrations from the hammer spring, No cant or bind issues when done correctly. Outside of the stop rod protruding out when cocked is has no faults that I have seen.
4 personal PCP's done with the same style ( Shared early in thread ) having all operate flawless with very tight velocity spread.
Cool to see the innovation, but don't find myself changing out whats already done 8) K.I.S.S. works
There is one potential huge drawback of that one, I have done some accuracy testing with it, and because the stop happens before the valve is struck, it's the equivalent to kicking the gun just before you shoot. Not good for accuracy at all. In my testing, shooting around 300 rounds now, the results are not good. Efficiency is great, as pr. expectations, but the resulting jolt to the chassis is throwing of the accuracy in a really profound, and unacceptable way.
I've solved this by moving everything to the hammer. I will post a picture as soon as Photobucket is back online.
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So, did anyone make a parts list for the marauder yet? thanks
+1
I'll probably just by one from WAR.
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Travis, do you have plans to offer an SSG for the 22xx platform?
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Well ... as designs get hashed out, tried & tossed for another in the on going search for the ideal SSG design ... The original idea which keeps all the spring / stop rod parts independent of the hammer has the most consistent hammer strike of all IMO. No secondary vibrations from the hammer spring, No cant or bind issues when done correctly. Outside of the stop rod protruding out when cocked is has no faults that I have seen.
4 personal PCP's done with the same style ( Shared early in thread ) having all operate flawless with very tight velocity spread.
Cool to see the innovation, but don't find myself changing out whats already done 8) K.I.S.S. works
There is one potential huge drawback of that one, I have done some accuracy testing with it, and because the stop happens before the valve is struck, it's the equivalent to kicking the gun just before you shoot. Not good for accuracy at all. In my testing, shooting around 300 rounds now, the results are not good. Efficiency is great, as pr. expectations, but the resulting jolt to the chassis is throwing of the accuracy in a really profound, and unacceptable way.
I've solved this by moving everything to the hammer. I will post a picture as soon as Photobucket is back online.
They ALL stop before hammer impacts poppet stem ! As i see designs the ONLY version that does as your describing requires stop rod to be integral with hammer having the sliding rear collar. That design is super critical on allowing MUCH clearance on rear because when hammer cants being cocked and held by sear, stop rod go's sideways too :P
By keeping the stop rod mass at a minimum and incorporate a stop bumper, vibration or "Bump" of the stoppage of the stop guide parts independent of hammer becomes nil. * Big & heavy bolt used as a stop rod ... would agree ;)
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First to say, thanks to rsterne for what he shared such a simple and great invention.
I have a Marauder (but it's regulated) and I made a basic version of SSG for like $2. Yeah, it protrudes out from the back of the gun but it did the job done. For $2!
All you need is:
1. Short screw which will replace striker screw and thus extend the stroke of the hammer by at least 0.5" and
2. I think 6x80mm bolt (metric size, imperial is something like 0.25" diameter and 3" long) and nut for that bolt, maybe some o ring that will remove some metal to metal noise.
I was using all original Marauder parts, just the striker screw is replaced. Pictures is just bellow in attachment (not the final version, it will be shortened and painted.)
I do not understand why anyone would want to pay $95 :o for the same thing but just "nicer packaged"? :-\
EDIT: I also have Crosman 2240 and just have to drill the end cap, If someone want I can post the pictures and specs.
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Because mines NOT the same thing, My version doesnt have that finger pincher rod coming out the back and to make it all internal you have to mill/lathe parts and put set screws in, tap holes refinish parts etc. very time consuming. I had that design and it works great until you rip the flesh off the top of your hand like I did and that $95 will sound awfully cheap lol
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There is one potential huge drawback of that one, I have done some accuracy testing with it, and because the stop happens before the valve is struck, it's the equivalent to kicking the gun just before you shoot. Not good for accuracy at all. In my testing, shooting around 300 rounds now, the results are not good. Efficiency is great, as pr. expectations, but the resulting jolt to the chassis is throwing of the accuracy in a really profound, and unacceptable way.
I've solved this by moving everything to the hammer. I will post a picture as soon as Photobucket is back online.
The phrase "there's no free lunch" ALWAYS come to mind for me when someone comes up with something "new", "revolutionary", "beyond belief", etc.
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Do you have to remove the end cap to adjust the spring preoload? Seems like on pincher design, you would.
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Scott, I think the version I am currently using has the best potential overall.... The spring guide is separate from the hammer, free floating, and only has to pick up the mass of the small collar before hitting the valve to add to the hammer strike, therefore wasting none of the spring energy.... It acts like I_like_Irons version, with the guide attached to the hammer, but without the alignment issues.... I do agree, though, that the original version, with a light guide to minimize energy waste, and the disturbance to the gun just before hammer strike, has simplicity going for it, and does appear to have the lowest ES....
It will be interesting to revisit this thread in a year and see which versions have survived for the DIY guys (which is why I developed it).... and which direction the commercial versions take and which survive and their price point....
Steve, on the original "pincher" design as you call it (*LOL*).... you can adjust both preload and gap without disassembly, with just a screwdriver slot in the end of the guide, if you use a Nyloc stop nut....
TomG, the very first SSG made is on my .30 cal Grizzly, which has an 80 gr. hammer with nearly a 1" stroke, and the SSG guide assembly that comes to a crashing halt weighs nearly 20 grams (20% of the total 100 gr. weight).... The gun is extremely accurate, and doesn't throw "fliers", nor do I notice any disturbance of the gun when fired.... The gun only weighs a bit over 7 lbs. all up....
Bob
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I believe Tomg may be on to something. Accuracy trumps efficiency to me and most of the results seem biased towards efficiency. I tried the original design in a .25 Mrod using a 10# spring and accuracy went south badly. Tried a 6# spring and found if adjusted stop length to just starting to hear hammer bounce my accuracy returned to normal but efficiency suffered . Seems the more hammer gap dialed in the groups opened up past 40 yards or so and at 70 yards became 4 inches or larger for 5 shots. Speculating the 10# spring was whacking the end cap hard enough to effect the shot while still in the barrel?
With 6# spring if it walk the tightrope between hammer bounce & stop nut contact I seem to regain some acceptable accuracy with increased efficiency.
Not trying to rain on anyone's parade, just giving my observation
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The original version works AWESOME and costs only $10 to build at most! It will greatly improve your gun for the least mount of money BUT As a retailer I cannot put a product into the market place that can potentially hurt someone thats what took me down the road I went down and why my SSG isnt $30. Your not just getting a spring and a guide your getting all the parts pictured above machined and pre set up for and easy drop in. For the do it yourselfers The original design is simple works well and you can easily remove plus its dirt cheap. I think that sums it up for me.
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For sure, if I was selling them, I would NOT want a design that could pinch you.... Murphy's Law will get you every time.... "If it CAN happen, it WILL happen"....
Bob
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EDIT: I also have Crosman 2240 and just have to drill the end cap, If someone want I can post the pictures and specs.
Yes post what you have come up with for the 2240. Thanks.
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"TomG, the very first SSG made is on my .30 cal Grizzly, which has an 80 gr. hammer with nearly a 1" stroke, and the SSG guide assembly that comes to a crashing halt weighs nearly 20 grams (20% of the total 100 gr. weight).... The gun is extremely accurate, and doesn't throw "fliers", nor do I notice any disturbance of the gun when fired.... The gun only weighs a bit over 7 lbs. all up...."
Bob, I am not arguing your findings, or anyone else's.
However the fact is that the spring stop happens right before the valve is hit. So what it is hitting is of concern in my book.
It might be that on that particular gun the hit is so consistent and the propagation so predictable that it does not affect the accuracy. As you well know, harmonics are always present, but if the harmonics act the same way every time, the accuracy stays the same.
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... and in most conventional PCP airguns the valve is hit by the relatively massively heavy striker/hammer BEFORE the pellet starts to move down the barrel. I doubt there is more than a 0.001 second difference between the 'impact' of the SSG'd spring stop and the valve being hit SO much harder by the hammer. Both are, in most PCPs, inline with the bore, zero geometrical offset with the bore meaning zero tangential momentum imparted to the barrel, which means the gun is just being encouraged to react in the same direction the pellet is travelling anyway. I'm no physicist, but in what I've seen with the SSG installation in my 2240 carbine, the pellet moving relatively slowly down the 18" barrel compared to the kinds of power most guys are talking about in this thread, there has been no change in the tiny groups I get with the gun. No POI shift either, comparing to before the SSG's installation. Of course it'd take someone with the right kind of sensor array to measure differences in behaviour... perhaps a laser pointed at a mirror mounted to the side of the muzzle, the reflected beam hitting a graph on a wall across a workshop and tests done before and after SSG installation to determine amplitude and orientation of any detectable changes in bright red dot motion. I'm not going to bother setting that up as I don't see any accuracy changes in my situation so there's no point. Don't notice any difference in the firing behaviour of with my 2260 either, but it's not scoped yet so can't attest to accuracy changes.
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Happy to read we're all acting civil here as we debate the PRO / CONS of each design shared 8)
Obviously I'm one of the few here that competitively shoot where BOTH accuracy & efficiency are required.
Certainly the VERY LOW mass configuration I came up with ( Hammer / Stop rod Etc ... ) was purpose built to aid Tune / design attributes already in place. .... So said design for others may be entirely wrong & I get that.
So really no argument of whats best really exists here ;)
Now ...
Back to talking about other variations, indeed see the version that has the STOP GUIDE as a "cartridge" being a free floating devise independent of hammer while also free of rear cap to likely be the best of all compromises in designs shared to date.
So question after a few statements becomes this ???
We understand we're throwing the hammer at poppet stem independent of hammer spring energy ;D
We understand doing so that hammer bounce between poppet and end of stop rod kills hammer bounce ;D
We understand as hammer is cocked and held, cant and alignment issues need to be addressed to keep it all bind free ;D
And ... with a stem of stop rod out the back fingers or hand injury is a possibility :P
** Question becomes one of secondary vibrations independent of the hammer moving from being at rest ( Cocked then released ) striking poppet ( Acceleration ) then the sudden (Deceleration) of hammer as it strikes poppet. This is a two way bump that is 100% physics only mitigated with lower weight / mass.
So if we look JUST AT THE SSG DEVISE ( Hammer spring, Stop rod, Collars & nuts etc ... )
What is the influence it contributes to the shot cycle ???
I see a spring that stays with hammer have coils oscillating wildly just as the shots happening !
I see a floated SSG device independent of hammer and rear cap to be a SECOND loose part very similar to hammer rattling between poppet and SSG rod & SSG rod also rattles loosely between hammer and rear cap.
I see the original design as presented having ONLY the bare hammer as the loose part, having all the SSG components under tension and not contributing to vibrations AFTER the shot cycle has been initiated.
* Or at least view it as the lessor contributor of vibrations created upsetting accuracy.
Really don't know ... but is a subject worthy of further discussion IMO.
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I personally didnt see any changes with POI with original version or My version. I would suggest if that your having issues you need more preload on spring and a closer rod clearance, I run mine at around 20 thou with a 12lb spring under tension.
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Gerard, the hit of the SSG and a hammer hitting the valve stem are two very different hits. One is hitting the rear-cap/tube with an absolute stop, no give. The hammer hit the valve stem which gives and moves fwd a little bit, then goes back. I have not measured how fast the hammer moves fwd, but I am willing to bet it is by a huge factor slower than the pellet is leaving the barrel. Whereas harmonics move through metal much faster than both pellet or hammer.
Let's compare apples to apples.
I am sure as more data is coming in, we'll get a result pool that will help build some empirical data.
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I'm didn't find any accuracy issues using an SSG on my .25 Mrod (before the gun died), on my brother's gun, or on my .177 Mrod. My design is the basic design except I use one nylon lock nut to set my gap distance.
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First to say, thanks to rsterne for what he shared such a simple and great invention
EDIT: I also have Crosman 2240 and just have to drill the end cap, If someone want I can post the pictures and specs.
I am a 2240 kind of guy since selling my Marauders so I'm very much interested in your pictures.
Carl
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TomG.... are you using an O-ring to stop the rear nut?.... Perhaps just that slight cushion is the difference.... In terms of the timing, that is all easily calculated, and of course depends on the gap between the hammer and valve stem at the point the guide stops.... However, since the total time the valve is open (round trip) on a typical PCP is only about 1 mSec (0.001 sec.) and the total time the pellet is in the barrel is about 2 mSec.... and the time the hammer takes to cross the gap only a very small fraction of a millisecond.... there is no question that with the speed of sound in steel a disturbance to the gun from the guide collision COULD move the gun while the pellet is in the barrel.... Whether or not that is measurable, when you compare the mass and velocity of the guide to the mass of the gun, is another matter.... My gut feel is that just the introduction of that O-ring to (drastically) reduce the deceleration rate of the guide may be enough to eliminate any disturbing effect by it.... but these are the things that will show up, and be conquered, in time....
Bob
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I have not used a o ring. And you might be right Bob, the margins are so small in terms of timing, that that cushion is the difference thats needed.
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I have not used a o ring. And you might be right Bob, the margins are so small in terms of timing, that that cushion is the difference thats needed.
No O-ring having stop rod smack rear cap crisply ... You INDEED create a shock vibration / motion to the shot cycle !!
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The original version works AWESOME and costs only $10 to build at most! It will greatly improve your gun for the least mount of money BUT As a retailer I cannot put a product into the market place that can potentially hurt someone thats what took me down the road I went down and why my SSG isnt $30. Your not just getting a spring and a guide your getting all the parts pictured above machined and pre set up for and easy drop in. For the do it yourselfers The original design is simple works well and you can easily remove plus its dirt cheap. I think that sums it up for me.
Does that other "$30" device have a possibility of pinching? or hurting in some other different way?
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I don't think we should be dragging this thread off track debating Commercial over DIY versions.... Let's stay with what works, doesn't work, and why.... and let the marketplace decide if there is, or isn't, a market for the SSG commercially.... Some guys can roll their own, some can't and want to purchase, it's as simple as that.... Maybe someday a manufacturer will start installing them OEM.... and then we can comment on how well they work (or don't).... and then start modding them.... *LOL*....
Bob
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Im with you 100% Bob plus its just plain frustrating trying to explain something new to most people who never seen touched or tested one. Lots of ways to do it and im sure there will be more to come.
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The .22 Marauder I have the SSG in is more accurate than when I started. This one is an 8 gram affair, with a smoooshy o-ring for a bumper between the depth stop and the spring preload nuts. With the preload and spring k I am running it *NEEDS* to be a 90D one, perhaps even a polyurethane one. Fortunately there is an o-ring store down the street from work...:)
The hammer interface has a rounded end, cut to the old OE spring diameter and the striker set screw flush with the hole in the hammer. Cock binding does not seem to present me any issue.
The next implementation will be done floating and use smaller OD springs. The endcap is cut out to 9/16-20 threads so I can run the jam nuts through it, and still have enough engagement of the washer/collar. Stick-out should be minimal, and if I make the depth nut long enough nothing will stick out the back past it.
The .224 will get the floating one, maybe with the .42 springs, maybe with .36 OD...probably going to try the .420 so I can get an apples-apples test when running the same pre-load.
If the results are not better, I will put it back to the way it is...:) High preload is a good thing. With the pellet-shooting .25 I want to do a direct compare to efficiency/shot count v. the Wicked NBH.
cheers,
Douglas
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Bob, on the last diagram on post 356, one does not need to make a socket for the collar( in the depth nut). Lock up the jam nuts and chuck the screw in a lathe and take a bit off their corners. The nuts will then act as the rear guide. This coupled with a depth adjuster long enough to contain the stroke will render the device 'safe' from thumbs stuck where they might otherwise get into harm's way. For 10-32's this is likely going to be OTO .400-.405 diameter...that will leave me to use a Z drill of .413. and cut the collar at something less than 9/16-20 minor diameter.
Or...if we can be sure the depth nut is well within the end cap, the collar can be cut to its minor/tap drill dia and leave the nuts a bit more clearance in the depth nut. It is certainly useful to run 3" of spring as this app can yield a bit more length for it to hide in, at least with the Gen1 end caps.
cheers,
Douglas
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Yes post what you have come up with for the 2240. Thanks.
I am a 2240 kind of guy since selling my Marauders so I'm very much interested in your pictures.
Carl
First to say, my 2240 have a little shortened hammer spring to get the most usable shot string from a single CO2 cartridge.
Now, here is what you need to make SSG for Crosman 2240. In my local store all the parts from the picture was about $0.25! :D
1. One bolt, approximately 2" long, thick exactly enough to go through the OEM spring of 2240,
2. Two nuts that matches the size of the bolt, or one nut with plastic lock (if you want to using only one nut, then you have to made thin slot for screwdriver on the bolt for tuning),
3. Two washers and two o-rings that matches the size of the bolt (not necessarily required).
(http://s20.postimg.org/4ukt3ra4d/2240_SSG_1.jpg)
Then, you have to measure the bolt diameter and find the drill bit that's just a little bit bigger than that. My bolt was 0.189" (4.8mm metric) and I was used 0.2" drill bit to drill the end cap.
You need to drill from the inside because it will be perfectly centered (it is tapered inside, at least in my case). After you have drilled it, you may have to sand the hole.
(http://s20.postimg.org/3tkkemt4t/2240_SSG_2.jpg)
Also, if the head of the bolt is bigger than a hole in the back of the hammer, you have to process the head until it can freely go in the hammer.
And the last, you need to assemble your SSG device for 2240 but that's easy part.
I don't need to use washers on this, but they would be required if you want to increase power. O rings are used to reduce impact.
Length of the bolt remains the same because you want to have free floated hammer, you just have to put washers inside the end cap and in that way you will get more pretension on the spring, thus more power. ;)
(http://s20.postimg.org/eufpjnldp/2240_SSG_3.jpg)
My string is the same as I tuned it earlier, but with much less noise and without burrrrrrppppp...
AVG speed was something like 375fps with JSB Exact Heavy 18.13gr (5.6-5.7fpe) but I don't really want to measure a whole string. (it's that long) 8)
That's it, enjoy your 2240 with SSG! ;)
PS: Bigger pictures are in the attachment!
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Thanks 88, that looks perfect for the Crosman co2 pistols. Don't really need to worry about pinching like you do on the Disco and Gen 1 Mrod. Going to the hardware store today for bolt and nuts.
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thelast88 thanks so much for the great pictures and your insider's information. Now I'm off to my spares boxes to find the pieces I need to put one of these together.
Carl
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thelast88, +1 thanks for the pics. And super duper thanks for the tip on drilling the cap from the back to keep it centered!
Blue
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Working on the lower power end, but it's been educational.
Test rifles: (.177 left / .22 right):
(http://i157.photobucket.com/albums/t50/ribbonstone/HiPaC/57f2cb70-38dc-48a1-92b7-925ee7de27d5.jpg) (http://s157.photobucket.com/user/ribbonstone/media/HiPaC/57f2cb70-38dc-48a1-92b7-925ee7de27d5.jpg.html)
Simple SSG:
(http://i157.photobucket.com/albums/t50/ribbonstone/HiPaC/2e82b5a2-6318-4d40-96f1-f883871e9713.jpg) (http://s157.photobucket.com/user/ribbonstone/media/HiPaC/2e82b5a2-6318-4d40-96f1-f883871e9713.jpg.html)
(http://i157.photobucket.com/albums/t50/ribbonstone/HiPaC/12c7bd26-5d44-4f49-b10a-7ca2e97efc41.jpg) (http://s157.photobucket.com/user/ribbonstone/media/HiPaC/12c7bd26-5d44-4f49-b10a-7ca2e97efc41.jpg.html)
Looking for the most shots for the least air use, pretty much ignoring energy.
Tried for a more exact efficiency calculation, taking my time to get accurate readings of the fill pressures and limiting the test to the sweetest of the sweet spot (trying to only test in the top of the curve, avoiding the up and down slope of the graphs).
Been adjusting in small steps, just getting velocity readings, looking for the best air use and ignoring power (for the time being). No doubt about it, lower power is more efficient with these two.
Ended up that really low power would need some more mods (smaller transfer ports would be my guess). Past a certain level, the velocity became more erratic with occasional wildly slow or wildly fast shots cropping up. That “certain level” seemed to be about 7 foot pounds for the .177 and about 10 foot pounds for the .22.
Didn’t notice the erratic velocity swings at higher energy levels, but efficiency quickly decreased.
So for the efficiency test, stayed in the low energy area and just tuned for the best shot count/energy ratio I could find.
The “CHEAT” for high efficacy numbers is to stay in the best-of-the-best pressure range (the sweetest of the sweet spot). The low speed shots at the up slope and down slope of a graph tend to pull the average velocity down.
So I stuck to the 30 shots either gun can give in the best middle range.
Filled each to 1900psi.
Shot 30 shots on target getting velocity readings.
Checked remaining pressure after the 30 shots.
.177 test:
(http://i157.photobucket.com/albums/t50/ribbonstone/HiPaC/7be6bd45-577d-46b8-9836-dff04133c125.jpg) (http://s157.photobucket.com/user/ribbonstone/media/HiPaC/7be6bd45-577d-46b8-9836-dff04133c125.jpg.html)
.177/2260 ended up at 1400psi (so 1900psi to 1400psi of air used from a 72cc volume). The 8.4gr JSB’s in the .177 had a high of 687fps and a low of 670 fps in those 30 shots (spread of 18fps over 30 shots...about 2 1/2%). That’s only 8.6 foot pounds, but a good string of 30 shots for a non-regulated little rifle.
.22 test:
(http://i157.photobucket.com/albums/t50/ribbonstone/HiPaC/a9959348-3936-4efb-a885-4181be0ab2f0.jpg) (http://s157.photobucket.com/user/ribbonstone/media/HiPaC/a9959348-3936-4efb-a885-4181be0ab2f0.jpg.html)
.22/2260 ended up at 1300psi (so 1900psi to 1300psi of air from a 76cc volume. This was a prototype HiPac unit that was a little bit longer than what became standard). The 15.9gr. had a high of 578 and a low of 563 in those 30 shots (a spread of 15fps over 30 shots...about 2 1/2%).
Works out to about 1.7 FPE/cuin for the .177 and 1.8 FPE/cuin for the .22.
(BTW: Rather than look at the accuracy as a .177 vs .22 thing, look at it as an LW barrel (the .177) vs a Crosman barrel (.22) thing.)
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Going to pull mine out of the 2240 sometime this weekend and pop it into a .177 cal 22xx ish pcp (custom tube and internals). Current tune is 22 shots from (fps) 700 to 725 and back to 700 w/10.3gr JSB on a 2000psi fill.
Already pretty quiet and no perceptible bounce...curious to see what happens. :D
(http://i245.photobucket.com/albums/gg76/gippeto_album/177pcp_zps56fb568e.jpg) (http://s245.photobucket.com/user/gippeto_album/media/177pcp_zps56fb568e.jpg.html)
Al
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Work in progress.
Remind me of 2 things:
1. I really need to pressure wash the patio.
2. This old .177/2240 HiPac conversion needs a little up-keep/refinish.
(http://i157.photobucket.com/albums/t50/ribbonstone/air%20pistol/4aad0925-012b-48b8-aa15-0cac7ce6bd61.jpg) (http://s157.photobucket.com/user/ribbonstone/media/air%20pistol/4aad0925-012b-48b8-aa15-0cac7ce6bd61.jpg.html)
Just started work with the SSG, but it’s showing promise.
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I am already seeing the set up gap decreasing some as the buffer o-ring gets crushed from the static pressure against it while action is not cocked ... So may i suggest this 8)
THIS IS NOT picking on any ones application ... but one to flag you guys on something personally felt needing addressed ;)
Those doing the conventional stop rod out the back ... BUFFER O-ring/s should really be captive to some degree on there O.D.
As an o-ring gets crushed between flat surfaces it GROWS IN DIAMETER as it becomes thinner from the crush.
By containing o-rings O.D. in a cup, thimble or counter bore you stop its outward expansion and keep the height more stabilized. Crush can still happen, it just does so inward and rings profile changes to a semi square rather than a pancake :P
Talking this ... (http://www.gatewaytoairguns.org/GTA/index.php?action=dlattach;topic=102095.0;attach=148912;image)
In the case of a double stack o-ring they will climb over one another and WILL NOT maintain there height so critical to maintain the gap needed. Suggested cup/thimble only needs to be @ 2/3 rds o-ring cross section to support it.
* This outside diameter can also be a simple counter bore in the end cap where o-ring comes to rest.
Something like this ...
(http://i1320.photobucket.com/albums/u532/scott_schneider1/DSCF9925_zps49iwpz28.jpg)
Anywho ... just suggestion on some finer tuning the parts of the system to get better long term consistency from your SSG set up ;)
Scott
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WOW guys lots of fine pics to see this morning! Outstanding work BRAVO!!
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Those doing the conventional stop rod out the back ... BUFFER O-ring/s should really be captive to some degree on there O.D.
As an o-ring gets crushed between flat surfaces it GROWS IN DIAMETER as it becomes thinner from the crush.
By containing o-rings O.D. in a cup, thimble or counter bore you stop its outward expansion and keep the height more stabilized. Crush can still happen, it just does so inward and rings profile changes to a semi square rather than a pancake :P
Scott
An easy way to make the cup for the o-ring is to use a nylock nut and grind the nylock end flat and thinner then remove the nylon insert and place the o-ring in the cup remaining. Of course you loose the locking feature of the nut but using a jam nut solves that.
I am liking this simple SSG on my 2300kt. I am only using it as a hdd and it works well on the pistol.
Brian in AZ.
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Im not seeing many chronograph readings posted come on people lets see some before and afters. Thats where the light will shine.
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Completely agree. I would really like to see those numbers with pressure usage.
I would really like to see Scott run a 1.8 (or greater) efficiency with a regulated .22 cal tuned around 20fpe. With a 3000 psi charge and 1000 psi reg setting.He should see nearly 150 shots on 1 fill under 2% ES.
Now that would make me buy a regulator.
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Completely agree. I would really like to see those numbers with pressure usage.
I would really like to see Scott run a 1.8 (or greater) efficiency with a regulated .22 cal tuned around 20fpe. With a 3000 psi charge and 1000 psi reg setting.He should see nearly 150 shots on 1 fill under 2% ES.
Now that would make me buy a regulator.
Sadly a .22 at 20 ft lbs is going to be not much different than a .177 at the same power.
Granted the larger bore "should be" more efficient, don't see it making that much different when we're already sipping such small amounts of air.
Taking Reg set point down to 1000# uses more air per shot and likely would require valve to be larger yet in port sizes to utilize this lower pressure. While you gain @ 600# more air to use, your using more per shot and not sure results would be any better ... and doubt they would be.
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Scott don't sell it too short yet. You would be the king of kings with that shot count.
I can already do 70 shots at at an average 22 fpe from 2200 psi to 1200 psi with my dual wire spring at 1.8 efficiency. I ran the numbers on Lloyds calculator and at 180cc (marauder with regulator) you should hit 150 shots from 3000 psi to 1000 psi using a regulator set at 1200 psi with a plenum of 1/2 fpe per fpe along with a transfer port sized correctly and valve spring on the heavy side.
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Scott don't sell it too short yet. You would be the king of kings with that shot count.
I can already do 70 shots at at an average 22 fpe from 2200 psi to 1200 psi with my dual wire spring at 1.8 efficiency. I ran the numbers on Lloyds calculator and at 180cc (marauder with regulator) you should hit 150 shots from 3000 psi to 1000 psi using a regulator set at 1200 psi with a plenum of 1/2 fpe per fpe along with a transfer port sized correctly and valve spring on the heavy side.
Not to clutter this thread .... Don't have an M-rod to try this on ... Both my .177 & .22 are already highly tuned and NOT getting fiddled with further.
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That's too bad Scott. There's nothing like having the best of the best.
Most people before Bob shared the SSG was happy with a .9 or 1.1 efficiency. Heck, I tried the short stiff spring last year with efficiency over 1.5 with proven results.
Your the go to guy with the reg set ups and resources for regulators.
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Scott thanks much for the tuning advise/heads up on making the best use of the O-rings. When I am making my endcap pieces for my simple SSGs I will take that into consideration.
Carl
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Those doing the conventional stop rod out the back ... BUFFER O-ring/s should really be captive to some degree on there O.D.
As an o-ring gets crushed between flat surfaces it GROWS IN DIAMETER as it becomes thinner from the crush.
By containing o-rings O.D. in a cup, thimble or counter bore you stop its outward expansion and keep the height more stabilized. Crush can still happen, it just does so inward and rings profile changes to a semi square rather than a pancake :P
In the case of a double stack o-ring they will climb over one another and WILL NOT maintain there height so critical to maintain the gap needed. Suggested cup/thimble only needs to be @ 2/3 rds o-ring cross section to support it.
Anywho ... just suggestion on some finer tuning the parts of the system to get better long term consistency from your SSG set up ;)
Scott
Pictures and some of the text removed to reduce the size of the post.
Scott, I know what are you talking, but it's just me experimenting, and, I really don't have any problem with two o rings stacked.
The spring are relatively low power and the o rings are tight on the rod, it didn't climb one over another in 100+ shots.
I will probably remove one of them a leave one alone, then shorten the rod for the width of that o ring and that's it.
Anyway, thanks for suggestion.
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Well did another SSG devise today on the TM-1000 FT gun. This one done having end of stop rod travel down into hammer body when cocked ( removing the kinetic striker & spring using its bore ), floating washer to be the stop shelf, spring support while other end of rod into a fixed base at tension adjuster cap.
NOTHING comes out the rear upon cocking with gun looking and acting 100% stock. And yes, it works ;D
That makes all the personal PCP rifles able to be SSG converted done. Dang what a great devise !!
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;D Ok so now somebody needs to start making some of the better designs to sell to those of us with no machine shop access and I would love to get one of the invisible designs for my .25 Marauder that is beginning to be a project rifle.
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Taking Reg set point down to 1000# uses more air per shot and likely would require valve to be larger yet in port sizes to utilize this lower pressure. While you gain @ 600# more air to use, your using more per shot and not sure results would be any better ... and doubt they would be.
Hi Scott, I will admit that I have never actually counted shot strings, but I am curious, is there a rule of thumb to go by when it comes to pressure vs efficiency and shot count? I am running a regulated .177 2400kt with a 24" barrel. The goal was to be able to push 10.34gr JSB heavies at 900fps, while on the knee of the curve. Originally, I was running at 1400psi, as suggested by rsterne, but then I lowered it to 1200psi and was excited that I was still able to get 900fps. Then I lowered it again to 1050psi (1100 with the bottle filled, and 1050 when just above set point), and am just barely able to achieve 900fps with these pellets. Granted, I am using more spring preload to achieve these results, but my thought was that since the air is at a lower pressure, it would be escaping at a lower rate, cancelling out the longer/wider dwell. Again, I have never actually counted shot strings. I thought this automatically equaled higher shot count, but your post contradicts this. When I shoot at 885fps, I am somewhere on the knee of the curve with 1000psi...
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Efficiency per shot on PCPs tends to go up with pressure, for a given FPE.... In a regulated PCP, however, the "headroom", or the difference between your fill pressure and setpoint pressure goes down, reducing the overall amount of air you have available.... Finding the best balance between the two will give you the most shots at a given FPE.... As you reduce the pressure (like aPpYe is doing), you will eventually get to the point that you cannot get the FPE you want, or you will be operating up on the plateau of the curve where the efficiency is terrible.... and even though you have more headroom (air) available, your shot count will drop.... This has nothing to do with SSGs, of course....
Bob
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Whoops! I apologize for that! Somehow I got the idea I was quoting from my 2400kt thread. In no way do I want to hijack this thread! Again, sorry about that Bob. I will continue discussion in my own thread.
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I too agree that this topic is about the SSG.
Maybe a new post needs to be started on using the SSG or short stiff spring for efficiency. Apparently most or all of you only experienced <1.5 efficiency and with that being said, new ways of tuning are about to come from it.
Even theories of lift and dwell at lower pressures may change for super high efficiencies that none of us have experienced.
I am still trying to bounce my head around how Lloyds efficiency calculator says that a 100psi drop from 2000psi or 3000psi or 1000psi has the same volume of air used. the only thing that changes is the pressure.
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Lloyd is 100% correct.... The amount of air used (molecules, or volume at NTP) is the volume of the reservoir times the change in pressure.... What you may be having trouble with, is that if you compress a given amount of air to 3000 psi, it takes up only half the space it would at 1500 psi.... so the energy it took you to compress that air is contained in half the volume at the higher pressure.... It follows, therefore, that 1 cc of air at 3000 psi has twice the energy of 1 cc of air at 1500 psi.... However, it has the same amount of energy as 2 cc of air at 1500 psi.... If you expand that 1 cc of air at 3000 psi.... or the 2 cc of air at 1500 psi.... back to 1 atmosphere.... both will occupy the same volume (207 cc).... and both will release the same amount of energy.... In both cases, you would get a 100 psi drop in pressure if you released the air from a 30 cc reservoir.... (29 cc / 30 cc) x 3000 = 2900 psi.... (28 cc / 30 cc) x 1500 = 1400 psi.... (100 psi / 14.5) = 6.9 bar x 30cc = 207 cc....
Actually, once you go above about 3500 psi, and certainly by the time you get to 4500 psi, there is LESS air in that 100 psi change of pressure, due to the Van Der Waals correction, as air no longer acts like an ideal gas as predicted by Boyle's Law.... Conversely, higher pressure air can accelerate a pellet more efficiently, which is why PCPs operating at higher pressure tend to be more efficient.... But again, back to SSGs....
Bob
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Yes I do believe lloyds calculator (and yours) is correct. Just hard to wrap the head around it. That's why I mentioned maybe a new post instead of here.
I am not sure the attachment is going to work. Winrar expired on the dumb PC :D
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Well did another SSG devise today on the TM-1000 FT gun. This one done having end of stop rod travel down into hammer body when cocked ( removing the kinetic striker & spring using its bore ), floating washer to be the stop shelf, spring support while other end of rod into a fixed base at tension adjuster cap.
NOTHING comes out the rear upon cocking with gun looking and acting 100% stock. And yes, it works ;D
That makes all the personal PCP rifles able to be SSG converted done. Dang what a great devise !!
This sounds really sweet! I think I understand your SSG configuration in the TM1000: does the tension cap adjust preload with the rod adjusting extended length? What caliber? Is your setup otherwise stock or do you have other springs and different weight hammer?
How much did your shot count or efficiency improve?
I have a 20fpe .177 TM1000 19" barrel with the stock dual hammer springs, stock hammer, inertia weight, etc., reg set at 120bar. If I were to try your config what spring should I use? Thanks!
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For Bob and any who may have found an interest in my Excalibre hammer mods from 10 years ago; viz in particular the experiments with free travel hammer and short strong home made springs.
This morning I got the old rifle out and stripped it down. It has mostly been used for rabbit extermination these last years as it is my only repeater.
I installed one of the old hammer units ( see the pics Bob posted for me back on page 23 ) which has a very short spring, so there is a lot of ballistic hammer free travel, and just one buffer "O" ring.
Without any other adjustments I shot a short string of 11 shots with JSB 15.9 gr pellets; then a long string of 49 shots, one plus 6 magazines, with Barracuda 21 gr pellets.
The start pressure in the 203 cc reservoir was 170 bar.
The short string to check things were functioning properly:
15.9 gr JSB Exacts.
11 shots from 790 to 820 fps. 15.9 gr JSB .22s.
2465 to 2305 psi / 170 to 159 bar.
806.27 av fps
22.9 av fpe
1.84 fpe/cuin
8.9 bar-cc/fpe.
15 psi/shot.
Obviously biased by being a short string in the near side of the climb to velocity plateau.
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The long string:
21 gr H&N Baracudas,
49 shots from 705.2 to 734.2 to 709.9 fps . That fastest shot was 5.4 fps faster than the next highest.
2465 to 1595 psi / 170 to 110 bar.
719.8 fps av.
24.2 fpe av.
1.60 fpe/cui.
10.3 bar-cc/fpe
18 psi/shot.
The last loctited transfer-port adjustment I recall as being out 4 turns on the interference screw. I know that that needs to be optimized for best results with this hammer unit so may go back to playing with it again.
Hope some find this of some interest.
Best regards, Harry.
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Very nice string, Harry, and excellent efficiency.... the first part shows how the HP end of the string is much more efficient, too....
Bob
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Well did another SSG devise today on the TM-1000 FT gun. This one done having end of stop rod travel down into hammer body when cocked ( removing the kinetic striker & spring using its bore ), floating washer to be the stop shelf, spring support while other end of rod into a fixed base at tension adjuster cap.
NOTHING comes out the rear upon cocking with gun looking and acting 100% stock. And yes, it works ;D
That makes all the personal PCP rifles able to be SSG converted done. Dang what a great devise !!
This sounds really sweet! I think I understand your SSG configuration in the TM1000: does the tension cap adjust preload with the rod adjusting extended length? What caliber? Is your setup otherwise stock or do you have other springs and different weight hammer?
How much did your shot count or efficiency improve?
I have a 20fpe .177 TM1000 19" barrel with the stock dual hammer springs, stock hammer, inertia weight, etc., reg set at 120bar. If I were to try your config what spring should I use? Thanks!
No picture .... so use your imagination 8)
But VERY similar to this drawing with proportions quite different in regards to spring/rod & spring depth within hammer. ;)
(http://i378.photobucket.com/albums/oo221/rsterne/Parts%20for%20Sale/SSG%20Loose%20Guide%20Stationary_zpszp4xodm4.jpg)
* Tho Do Not Agree on No energy being transmitted to hammer & will elaborate that below.
8-32 cap screw with head lathe turned to have clearance within the hammers 8mm kinetic striker bore.
Then made a Peek washer @ .100" thick with clearance hole in middle for the screw above, having an O.D. to be slightly loose within hammer spring bore. ( It rests on the shelf bottom of spring bore with the deep striker bore beneath it )
At the spring tension cap another peek part being a threaded Hat that screw anchors onto, has 2 shoulders to hold primary spring and secondary spring similar to OEM. The O.D. is that of end cap counter bore.
* Screw is assembled threw washer, then both springs screwed into end hat. Spring tension gets adjusted initially by varying spring rate of primary spring and length of inner spring to fine tune the tension within @ known OAL specs of the assembled cartridge.
So what you have is a floating spring cartridge affair that drops into the OEM hammer and gets covered by the tension cap that IS NOW USED to set the gap. Tension is slightly changing OAL of spring cartridge/ changing spring rate & length. Then end cap again sets the gap.
Now as action is cocked the head of screw is allowed to move down the removed striker bore and washer setting on the shoulder of spring bore is now compressed against the spring stack. Rod is attached to end hat so the assembly stays stationary as hammer is cocked.
Upon firing the hammer is driven forward in typical manor until head of screw contacts washer and the OAL of the SSG spring cartridge is stopped dead !
Hammer is now free floating just before it contact valve poppet in typical SSG fashion ;) ;)
Reason for using a Peek Washer and Hat was too minimize weight of the spring cartridge, because in this configuration as the head of stop rod impacts the washer stopping spring expansion it sends the spring cartridge assembly forward from the strike :P Kinetics 101 ... Lol
Being rear hat is also floating against the rear cap the entire spring cartridge is allowed to move forward or back.
Because we are creating potential for secondary impact or vibration choose to keep the mass and weight of SSG devise at absolute minimums ;)
Have done this now TWICE, first being with the OEM hammer where it worked but experience told me Dwell was still to much from excess hammer weight just not required.
So ... made a second hammer from Aluminum having a thin anti-wear nylon sleeve on the O.D. and a steel strike pip out front.
Also made it to have @ .300" greater stroke. Adjusted bores within so SSG would fit without a rod or spring change from OEM hammer.
Weight @ 1/3 that of OEM hammer. Needed a tad more spring energy but not really that much to get power back.
End result became Very Very similar to my LW hammer marauder tunes with the SSG devises ..... Muzzle report a SHARP SNAP !!
Not had time to run a string ... but so far air use is appearing to be SUBSTANTIALLY less now. ES #'s are staying +/- 3 fps as well.
** This done on a .177 cal 19 ft lb action w/21" barrel
Regards,
Scott
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So this replaces the hammer spring I take it? Is it still possible to get 60-70FPE out of a .25 Mrod with this? And if so can someone put up some strings doing so? I need to know before I order one from Travis.
Thanks for the help.
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So this replaces the hammer spring I take it? Is it still possible to get 60-70FPE out of a .25 Mrod with this? And if so can someone put up some strings doing so? I need to know before I order one from Travis.
Thanks for the help.
Hi just a note. This increases your shot count / efficiency of the rifle. If your rifle can't get there now it probably will not after this modification. To increase FPE you need energy. This is an air conservation arrangement. Same FPE with less air. That said his Spring in this modification, may produce Higher energy than what you currently have, but that is unknown. Where are you starting?
Drop Travis a line he is good at returning e-mails. Have any information on your current tune at the ready.
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The rifle is on the way. I'm planning a WAR valve with the 17 lb spring so it should be able to hit that power. But, if this replaces the 17lb spring no point in ordering it and the SSG. I'm looking to maybe get 12 shots at 60fpe vs 8 if the SSG will do it.
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The guy to ask is Travis, since it's his valve and his SSG.... I'm betting he has already tried it.... 8 shots at 60 FPE sounds pretty dismal, I can get that with a modded Disco.... You must be way up on the plateau, trying to wring every last fps out of it....
Bob
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Sorry Bob I should have clarified. I do not have the rifle yet. I Would be happy with 8-10 shots at 60-70fpe. That's why I'm contemplating the SSG. Any more is a bonus. It's going to be used for smaller hogs on my Texas trip as well as fox and coyote around home.
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Maybe we could start a few independant threads dedicated to the different "flavors" of the SSG's people are currently building.
This is a great thread and I want to give it a try but I'm not great at getting my brain to translate some of the technical drawings and this thread is a monster to sort back and forth through.
Maybe if we can get a more thorough walk through of steps needed to make them with more pictures or videos it would help me (and others) be able to stop watching on the sidelines and start joining the fun.
I know that the only thing holding me back is not being able to visualize exactly how things look, are made, and work together with more details and step by step instructions for making them at home.
Just a thought, thanks
Blue
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Maybe we could start a few independant threads dedicated to the different "flavors" of the SSG's people are currently building.
This is a great thread and I want to give it a try but I'm not great at getting my brain to translate some of the technical drawings and this thread is a monster to sort back and forth through.
Maybe if we can get a more thorough walk through of steps needed to make them with more pictures or videos it would help me (and others) be able to stop watching on the sidelines and start joining the fun.
I know that the only thing holding me back is not being able to visualize exactly how things look, are made, and work together with more details and step by step instructions for making them at home.
Just a thought, thanks
Blue
I Just want a parts list for a m rod.
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The rifle is on the way. I'm planning a WAR valve with the 17 lb spring so it should be able to hit that power. But, if this replaces the 17lb spring no point in ordering it and the SSG. I'm looking to maybe get 12 shots at 60fpe vs 8 if the SSG will do it.
On my .25 Mrod that could do 80fpe easy I couldn't break past 55fpe with the SSG. This is using a 14# spring. The SSG definately benefits from a strong spring. However it doesn't matter to me anymore. On a mostly stock .25 Mrod I got 32 shots at 40 fpe with a tight spread. I wouldn' trade the SSG for more power. The SSG corrects the Mrod's biggest flaw, inefficient air usage. I'd do a WAR valve and an SSG, accept whatever FPE your gun comes out with that gives you a good shot count, and never look back.
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There isn't a lot of room inside a stock MRod, so I can understand why you could find a limit to the FPE you can hit with an SSG without making the gun too hard to cock.... In order to gain all the advantages of eliminating hammer bounce and reducing cocking effort, without power loss, you will need a longer, softer spring, and the SSG will stick out the back of the gun.... That is not to say you have to use an SSG that will pinch your thumb, you may be able to contain it, but you will need a longer end cap to allow for the longer spring.... My Grizzly, which is the first gun I tried with an SSG, is a .30 cal gun and over 100 FPE, for example....
Bob
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Bob,
How does a longer softer spring help gain power compared to a short stiff one?
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Bob,
How does a longer softer spring help gain power compared to a short stiff one?
A lot of that has to do with getting sufficient pre-load set so bounce can't happen, then have sufficient stroke without incurring coil bind from the heavier wire gauge spring.
Short stiff springs sadly tend to have the lowest stroke potential.
JMO on said Q
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It doesn't, it allows you to get the same power with a lower maximum cocking force by using more preload.... Three examples using 1" hammer travel.... same average force (10 lbs.).... giving same hammer energy....
No preload, 20 lb/in. spring.... maximum 20 lbs.
5 lbs. preload, 10 lb/in. spring.... maximum 15 lbs.
8 lbs preload, 4 lb/in. spring.... maximum 12 lbs.
If you used the exact same wire size and coil spacing, the 10 lb/in. spring would, however, be twice as long to start with as the 20 lb/in. spring.... You would start with it compressed 1/2", and it would be compressed 1.5" when cocked.... Then it would have to have enough room for all the coils (twice as many) on top of that.... so it needs more space behind the hammer....
Bob
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There isn't a lot of room inside a stock MRod, so I can understand why you could find a limit to the FPE you can hit with an SSG without making the gun too hard to cock.... In order to gain all the advantages of eliminating hammer bounce and reducing cocking effort, without power loss, you will need a longer, softer spring, and the SSG will stick out the back of the gun.... That is not to say you have to use an SSG that will pinch your thumb, you may be able to contain it, but you will need a longer end cap to allow for the longer spring.... My Grizzly, which is the first gun I tried with an SSG, is a .30 cal gun and over 100 FPE, for example....
Bob
I may also be using too heavy of a bolt or have too much drag in the SSG's guide. As it stands I can't get enough "umph" to the valve stem without closing the gap too much. When the gap is optimal, I hit a FPE wall that I can only raise by going to a heavier spring. It doesn't bother me though. I'm satisfied with the SSG as it is.
Now on the .177 its a totally different ball game. I can run the gun as powerful as otherwise possible with the factory spring on the SSG. It takes very little power from the hammer to open the valve up to the desired power.
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What bullfrog and Bob says is one of the reasons why I am sticking with the short stiff spring for now on the marauder platform.
You just can't get the spring power from the SSG before it bottoms out (coil bind) with a reasonable design that doesn't stick far out of the gun. It works great for lower power, but a short stiff spring does the same (atleast for me).
I am not saying the SSG isn't good for the marauder platform. It has a specific job that is limited for power and power range. Now, if you go nearly full bore porting (which the marauder can not do) the SSG like Bob mentions in his grizzly at 100 fpe sounds good but isn't really apples to apples.
I made this video a year ago or so. Looks silly now :D Listen to shot signature and look at the power levels. This was with a nearly stock gen 2 marauder .22cal. Since then, I have opened everything up to as far possible. The power levels at 3000psi can now be made at 2000psi and the gun maxes out to 56 fpe with 25.39 grain. Sure good example of what porting can do. Most importantly, each shot was extremely efficient.
https://www.youtube.com/watch?v=0e4a3BP0X14 (https://www.youtube.com/watch?v=0e4a3BP0X14)
I think it was canniborrowsomeammo is running my short stiff spring in his 25 cal marauder with war valve. I think he hits in the high 90's FPE I just don't know what he can turn it down.
I look at it this way. Short stiff spring, cheap and simple with capabilities of 1.84 efficiency with extreme power ranges vs SSG elaborate/novel/expensive with the same efficiencies and with limited power capabilities.
It may sound like I am against the SSG but I am not. It has it place on the playground. There's a lot of people reading this thread and trying out the design along with selling them now. Its important (to me) that people know what they are building or buying and what it's capable of.
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I am still trying to get my disco .22 tuned with the available .040" spring I have and am ordering more springs. I couldn't get past 720fps with 15.89 JSB. I tried combining springs but would get coil bind. I needed to lengthen my endcap so I could use a longer SSG and spring. Then yesterday I got the bright idea to weld a 3/8 nut to my end cap and then i could use a longer spring. It worked and I am up over 800fps with a quick test.
I also noticed throughout this process, that if I dial it in so no gap it gets so much louder and I was over 910fps...basically like not having the SSG. Create that bit of gap and instantly much quieter, but I lose a lot of power.
I think I am on the right track. I made a 4" guide and threaded it for a long way and it sticks out and looks terrible but once I find the tune and power and shoot a string to confirm more shots and efficiency I will cut and clean it up, possibly make a shroud that will cover everything and prevent a pinched finger. Eventually I will probably move to the design that has less sticking out the back if possible.
Ordered .312 OD springs in .037, .041, .047 and .055 in 10" lengths for about $5 apiece so something should work.
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Just to clarify, my Grizzly is only 75% porting, and over 100 FPE in .30 cal.... The only reason I mentioned it is to point out that the SSG can be used in higher FPE applications, it is NOT limited to low power.... In fact, the first gun I converted in this thread to the SSG, basically a Disco with a 2260 air tube, is now turning out 57 FPE with JSB King Heavies.... When tuned with the 25.4 gr. Kings, it went from 5 shots to 7 with a narrower ES, at the very same 50 FPE, running on only 1880 psi.... That is NOT a low power output.... If the MRod isn't suited to maximum power with an SSG, you can hardly fault the SSG, can you?....
Bob
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Bob you right. No fault of the SSG.
The thing is, what you are showing is extreme modified guns using the SSG. Most or everything I have read that people are using the SSG for is for stock to semi stock guns.
Put an SSG in a stock marauder 22 or 25 and you will not achieve the power levels you used to get. You will need to de-tune to a normal FPE to even cock the gun before coil bind or make a 1.5 inch extension out of the back of the HS adjuster cap.
This doesn't flaw the SSG either. I have plans for it's use too during my experiments with running an extremely low pressure regulated gun for max shot count at a normal plinking hunting gun.
Run a war valve with an SSG and a stock length barrel in a 25 and you will not be able to tune over 60 fpe (using it with negative pre-load) without coil bind, way too excessive cocking, or an extension out the back.
Calculated out, that would be 25 shots at 60 fpe with a 1.58 efficiency from 3000 psi to 1800 psi. The spring force needed to achieve this with a stock hammer is approximately 15 lbs per inch compressed on a SSG guide to allow for .02" negative preload. The guide would need to stick out of the back of the gun a minimum of 1" to allow the spring to be long enough to not go bind before full cock.
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Shorty you didnt see my strings? They were all done with stock M-rods and I was able to shoot into the high 800s with out any spring bind you just have to mod the parts to allow for a longer spring to be used and it all fits inside the stock mrod. heres a bone stock mrod .25 and its easy tocock and the whole SSG is internal. I should have started this string 10 shots earlier but I was testing changes from spring to spring at a 2800psi fill.
Created: 01/18/16 06:14 PM
Description:
Notes 1: stock .25 cal marauder
Notes 2:
Distance to Chrono(FT): 1.50
Ballistic Coefficient: 1.000
Bullet Weight(gr): 25.40
Temp: N/A °F
BP: N/A inHg
# FPS FT-LBS PF
29 ERROR 3
28 846 40.37 21.49
27 845 40.28 21.46
26 850 40.76 21.59
25 855 41.24 21.72
24 860 41.72 21.84
23 854 41.14 21.69
22 864 42.11 21.95
21 862 41.91 21.89
20 863 42.01 21.92
19 865 42.21 21.97
18 868 42.50 22.05
17 871 42.79 22.12
16 860 41.72 21.84
15 866 42.30 22.00
14 867 42.40 22.02
13 865 42.21 21.97
12 870 42.70 22.10
11 871 42.79 22.12
10 864 42.11 21.95
9 866 42.30 22.00
8 866 42.30 22.00
7 860 41.72 21.84
6 855 41.24 21.72
5 846 40.37 21.49
4 858 41.53 21.79
3 846 40.37 21.49
2 847 40.47 21.51
1 847 40.47 21.51
Average: 859.2 FPS
SD: 8.6 FPS
Min: 845 FPS
Max: 871 FPS
Spread: 26 FPS
Shot/sec: 0.1
True MV: 859 FPS
Group Size (in): 0.00
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It doesn't, it allows you to get the same power with a lower maximum cocking force by using more preload.... Three examples using 1" hammer travel.... same average force (10 lbs.).... giving same hammer energy....
No preload, 20 lb/in. spring.... maximum 20 lbs.
5 lbs. preload, 10 lb/in. spring.... maximum 15 lbs.
8 lbs preload, 4 lb/in. spring.... maximum 12 lbs.
If you used the exact same wire size and coil spacing, the 10 lb/in. spring would, however, be twice as long to start with as the 20 lb/in. spring.... You would start with it compressed 1/2", and it would be compressed 1.5" when cocked.... Then it would have to have enough room for all the coils (twice as many) on top of that.... so it needs more space behind the hammer....
Bob
Thanks Bob!! I understand now!!
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Shorty you didnt see my strings? They were all done with stock M-rods and I was able to shoot into the high 800s with out any spring bind you just have to mod the parts to allow for a longer spring to be used and it all fits inside the stock mrod. heres a bone stock mrod .25 and its easy tocock and the whole SSG is internal. I should have started this string 10 shots earlier but I was testing changes from spring to spring at a 2800psi fill.
Notes 1:
Notes 2:
Distance to Chrono(FT): 1.00
Ballistic Coefficient: 1.000
Bullet Weight(gr): 0.00
Temp: N/A °F
BP: N/A inHg
# FPS FT-LBS PF
24 851 0.00 0.00
23 852 0.00 0.00
22 854 0.00 0.00
21 861 0.00 0.00
20 858 0.00 0.00
19 861 0.00 0.00
18 867 0.00 0.00
17 864 0.00 0.00
16 868 0.00 0.00
15 868 0.00 0.00
14 871 0.00 0.00
13 872 0.00 0.00
12 874 0.00 0.00
11 875 0.00 0.00
10 873 0.00 0.00
9 881 0.00 0.00
8 882 0.00 0.00
7 883 0.00 0.00
6 872 0.00 0.00
5 884 0.00 0.00
4 879 0.00 0.00
3 884 0.00 0.00
2 874 0.00 0.00
1 878 0.00 0.00
Average: 870.2 FPS
SD: 10.1 FPS
Min: 851 FPS
Max: 884 FPS
Spread: 33 FPS
Shot/sec: 0.1
True MV: 870 FPS
Group Size (in): 0.00
Sent from my iPho
Are you going to fabricate and sell the M-Rod SSG ?
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On bottom of page.
http://wickedairrifles.com/store.html (http://wickedairrifles.com/store.html)
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I can shave $10 off price if buyer wants to drill out their own hammer and use it. Also as a service for $50 send in your parts and I will machine and set up yours and include extra spring for tunning like with above. I can set them up fairly close so only small adjustments will be needed.
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On bottom of page.
http://wickedairrifles.com/store.html (http://wickedairrifles.com/store.html)
Thanks just ordered next a nice wood stock ;) ;D
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And another in .22 and all of these are internal SSG not getting anywhere near spring bind or hard to cock.
ated: 01/12/16 06:04 PM
Description:
Notes 1: bone stock marauder .22 with SSG
Notes 2:
Distance to Chrono(FT): 1.00
Ballistic Coefficient: 1.000
Bullet Weight(gr): 14.30
Temp: N/A °F
BP: N/A inHg
# FPS FT-LBS PF
58 881 24.65 12.60
57 889 25.10 12.71
56 889 25.10 12.71
55 895 25.44 12.80
54 882 24.71 12.61
53 886 24.93 12.67
52 889 25.10 12.71
51 883 24.76 12.63
50 881 24.65 12.60
49 890 25.16 12.73
48 896 25.50 12.81
47 894 25.38 12.78
46 895 25.44 12.80
45 891 25.21 12.74
44 904 25.95 12.93
43 892 25.27 12.76
42 904 25.95 12.93
41 895 25.44 12.80
40 905 26.01 12.94
39 894 25.38 12.78
38 899 25.67 12.86
37 892 25.27 12.76
36 911 26.36 13.03
35 908 26.18 12.98
34 911 26.36 13.03
33 909 26.24 13.00
32 891 25.21 12.74
31 897 25.55 12.83
30 907 26.13 12.97
29 900 25.72 12.87
28 912 26.41 13.04
27 914 26.53 13.07
26 898 25.61 12.84
25 895 25.44 12.80
24 891 25.21 12.74
23 898 25.61 12.84
22 911 26.36 13.03
21 913 26.47 13.06
20 895 25.44 12.80
19 900 25.72 12.87
18 891 25.21 12.74
17 911 26.36 13.03
16 901 25.78 12.88
15 907 26.13 12.97
14 903 25.90 12.91
13 887 24.99 12.68
12 918 26.76 13.13
11 906 26.07 12.96
10 899 25.67 12.86
9 899 25.67 12.86
8 896 25.50 12.81
7 900 25.72 12.87
6 894 25.38 12.78
5 893 25.33 12.77
4 896 25.50 12.81
3 882 24.71 12.61
2 888 25.04 12.70
1 ERROR 10
Average: 897.5 FPS
SD: 9.2 FPS
Min: 881 FPS
Max: 918 FPS
Spread: 37 FPS
Shot/sec: 0.1
True MV: 898 FPS
Group Size (in): 0.00
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Travis,
I did see your strings with the SSG. I'll be as honest as possible without trying to insult/disrespect/ or make it appear as if I am selling something. I think you made a great working SSG.
But,
I wish I was able to get one of those short stiff springs in your hands for some testing on the marauder platforms. It has the same efficiency as an SSG system. More of a power range. No modifications to the gun. Still have control over the throw. And will not cost your customers 100 bones. Heck it can take your war valve from 35 FPE up to 85 FPE with just adjusting the HS with efficiencies of 1.3 to 1.8.
Shoot me a PM and I will send you some for yourself to try out. I will even show you how they are made and with what material. All I ask you is to have an honest opinion of them.
-
I understand what your saying shorty BUT Ive already been down that short stiff spring road and the SSG for one cocks WAY easier and is far more adjustable across the spectrum. Your SSG wasnt made correctly or implemented well or you would see that yourself. I have far too much data that tells me the SSG is right now the best thing going. Easy to cock/spring changes easily/Beginners can tune/can be adjusted from-0 to max with ease etc etc. Maybe you should start a short stiff spring thread this doesnt seem to be the place for it in the SSG thread IMHO. Shorty do you have some strings you can post of short stiff spring in 50fpe gun or around there I have never seen and effiecency of 1.8 using any type of spring alone in anything put a very low powered gun or high fill pressure gun with short shot count. Ive posted more strings then everyone combined. This is also not meant to call you out or doubt you but my personal experience says SSG wins hands down.
-
The table was from a long time ago with just TP and exit port matched at .141" using the short stiff spring.
Things are much different now. Remember when I converted this gun to .357 , http://www.gatewaytoairguns.org/GTA/index.php?topic=91575.20 (http://www.gatewaytoairguns.org/GTA/index.php?topic=91575.20)
Efficiency at 80 fpe was 1.37.
If you want me to post the strings I can. I keep them all stored on my PC. Just thought a table is a little more presentable. Lot's of it is old data from last year.
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shorty, I have to admit, those are great results.... I'm impressed.... You don't really have any before and after comparisons, but your results at 25 FPE are comparable to what Harry got with his Excalibre a decade ago.... and are very good for the power levels.... I do notice that as you push the power, the efficiency REALLY drops off, though, which is to be expected because the spring no longer has negative preload.... I've used lots of short stiff springs along the way, and I've never achieved those sorts of numbers, although as I said before the efficiency is definitely better than a conventional preloaded spring.... Perhaps the reason was that I have never really been interested in the lower end of the power range, which is where your numbers are particularly stunning.... I'd noticed how quiet the gun is when you back it off a ways, but never really explored that part of the power range.... What I didn't like was how hard the gun was to cock when you get up onto the knee of the curve, pushing the power like you did in the two right hand columns, where the efficiency is back to normal.... If you've solved all those problems, you are to be congratulated....
Bob
-
They have been solved with 75% matched porting and extra hammer travel.
I was asked to no longer post on the SSG thread.
-
I didnt ask you NOT to post in the SSG thread I said in writing that you should start another thread about the Spring. I think it will have a life of its own if you do.Otherwise well have to clump that in and oring buffers and regulators etc. I have tested all kinds of short stiff springs ,Bob also and they require far to much cocking effort and bind very easily and If you have to match port the valve to get where the SSG is now then when you match port the SSG youll still be behind lets not forget how easy it is to tune and SSG compared to and conventional Spring/ guide arrangement. One only needs two get two things to set full curve. Fill pressure at crack and starting FPS wanted for curve the SSG will balance out the rest. Plus spring changes are all external. If making a simple spring change was all it took all the manufacturers would have done it and Many people, SMART PEOPLE would have done it by now. Your results are good and about what Ive seen doing what your doing maybe a little better but still not as good as the SSG
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Shorty, any chance you're an old FT shooter? Those folks
were all using stiff springs with no preload back in the 80's.
Ron
-
I was curious what I could get for efficiency using the SSG.... so I took my 2260 HPA, which is regulated at 1600 psi, and started dialing back the power and recording the pressure drop for 20 or 30 shots, using 18.1 gr. JSBs.... Here is what I came up with....
(http://i378.photobucket.com/albums/oo221/rsterne/22%20PCP/2260%20HPA%20Efficiency%20SSG_zpsudxlco2f.jpg) (http://s378.photobucket.com/user/rsterne/media/22%20PCP/2260%20HPA%20Efficiency%20SSG_zpsudxlco2f.jpg.html)
This is the first time I have had an efficiency greater than 2.0 FPE/CI.... At just under 12 FPE, I got 2.12 FPE/CI, which is 7.7 barcc/FPE.... That would give me 250 shots per fill on the 13 CI tank.... Adjusted for 23 FPE, the efficiency would be 1.7 FPE/CI and 100 shots per fill.... The way the gun is normally tuned, at 37 FPE, I can actually shoot down to 1400 psi without velocity drop, and I get 60 shots (6 mags.)....
Bob
-
Wow!!! 2.12 FPE/CI!!! That is awesome Bob.
-
... At just under 12 FPE, I got 2.12 FPE/CI, which is 7.7 barcc/FPE....
Bob,
What kinda of ES are you getting at that level? When I de-tuned my gun reg'd at 1500 (and shooting 20fpe)the ES doubled when shooting it that low.
-
I honestly didn't pay any attention.... I shot 30 shots through the Chrony and only wrote down the average.... If you are just plinking at 532 fps, that would imply close range, so does it really matter?.... I guess it would if you were building a gun for 10M competition, but otherwise, even a 10% ES would be insignificant for minute of pop-can.... The 250 shots, on the other hand would be pretty KEWL!....
For that string, I was working with a gap of about 1/4".... If the ES was important, I would use less preload and/or a weaker spring and way less gap....
Bob
-
.. If you are just plinking at 532 fps, that would imply close range, so does it really matter?....
I guess not, sorry I asked. You guys are the best, thanks! Imoutahere
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Nothing wrong with the question, just not something I considered important enough to bother recording.... Didn't mean to be arrogant.... :-[
Bob
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And another in .22 and all of these are internal SSG not getting anywhere near spring bind or hard to cock.
ated: 01/12/16 06:04 PM
Description:
Notes 1: bone stock marauder .22 with SSG
Notes 2:
Distance to Chrono(FT): 1.00
Ballistic Coefficient: 1.000
Bullet Weight(gr): 14.30
Temp: N/A °F
BP: N/A inHg
# FPS FT-LBS PF
58 881 24.65 12.60
57 889 25.10 12.71
56 889 25.10 12.71
55 895 25.44 12.80
54 882 24.71 12.61
53 886 24.93 12.67
52 889 25.10 12.71
51 883 24.76 12.63
50 881 24.65 12.60
49 890 25.16 12.73
48 896 25.50 12.81
47 894 25.38 12.78
46 895 25.44 12.80
45 891 25.21 12.74
44 904 25.95 12.93
43 892 25.27 12.76
42 904 25.95 12.93
41 895 25.44 12.80
40 905 26.01 12.94
39 894 25.38 12.78
38 899 25.67 12.86
37 892 25.27 12.76
36 911 26.36 13.03
35 908 26.18 12.98
34 911 26.36 13.03
33 909 26.24 13.00
32 891 25.21 12.74
31 897 25.55 12.83
30 907 26.13 12.97
29 900 25.72 12.87
28 912 26.41 13.04
27 914 26.53 13.07
26 898 25.61 12.84
25 895 25.44 12.80
24 891 25.21 12.74
23 898 25.61 12.84
22 911 26.36 13.03
21 913 26.47 13.06
20 895 25.44 12.80
19 900 25.72 12.87
18 891 25.21 12.74
17 911 26.36 13.03
16 901 25.78 12.88
15 907 26.13 12.97
14 903 25.90 12.91
13 887 24.99 12.68
12 918 26.76 13.13
11 906 26.07 12.96
10 899 25.67 12.86
9 899 25.67 12.86
8 896 25.50 12.81
7 900 25.72 12.87
6 894 25.38 12.78
5 893 25.33 12.77
4 896 25.50 12.81
3 882 24.71 12.61
2 888 25.04 12.70
1 ERROR 10
Average: 897.5 FPS
SD: 9.2 FPS
Min: 881 FPS
Max: 918 FPS
Spread: 37 FPS
Shot/sec: 0.1
True MV: 898 FPS
Group Size (in): 0.00
. That looks like an all day sucker. Wow
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I wish Travis would post his starting and ending pressures.... Nice loonnngggg string for sure....
Bob
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Bob I should and will from now on but almost ALL the mrod tunes are from 2800 to 1800psi give or take 50psi, its the sweet spot on the Mrod valve in stock format. Ps woke up with one *(&^ of a headache lol.(inside joke)
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Assuming that was the pressure drop (1000 psi = 69 bar) on that string, on a stock 215 cc (13.1 CI) MRod tube, that works out to a total of 905 cc of air.... You had 58 shots averaging 898 fps (25.6 FPE) which is a total of 1485 FPE.... That gives an efficiency of 1.64 FPE/CI.... Crosman, are you listening?.... ::)
Bob
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I have my doubts as to whether Crosman is listening, but as a owner and lover of a exceptionally air hoggish .25 Mrod, I'm listening for sure. That many shots per fill would explode the fun factor of the .25 while reducing the wear on my hand pump and I. The external home brew SSG looks awesome/cheap/gratifying/reversable but WAR all internal is looking too good to resist for me. If I try to set the hook of airgunning on someone I'll likely use my .25 marauder as the bait with its accuracy, repeater action, and authoritative 40FPE smack. The internal SSG wouldn't require any explanation or cautions when passing around to friends and family to start their airgun addiction. Crosman can reimburse me for such promotion later.
Mr Bob, thanks for sharing this nifty mod with the community!
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I sold all my first run of the Sterne SSG(30) and Im building more now. This will be fun to see people using this tec. and posting results. Cant wait to see some strings. Crosman you just keep doing what your doing LOL I need the work ;D
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I sold all my first run of the Sterne SSG(30) and Im building more now. This will be fun to see people using this tec. and posting results. Cant wait to see some strings. Crosman you just keep doing what your doing LOL I need the work ;D
I was going to wait to start the mods on my marauder so now I will just need to get the War valve that much sooner and start my mods sooner and skip the wood stock for a little longer ;D
-
This thread is beyond sticky worthy.......mods?
(http://upsidedownmoon.tripod.com/sitebuildercontent/sitebuilderpictures/22a.jpg)
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OLDPRO any work on a drop in for the disco
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Disco and Prod are in the works
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Thanks Will be waiting with shovel to dig up mason jars!!
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Did a Theoben Rapid MK II in .22 cal today .... reverse floating type again with head of stop rod traveling forward into hammers "removed" kinetic striker bore.
Results were absolutely as expected 8)
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Did a Theoben Rapid MK II in .22 cal today .... reverse floating type again with head of stop rod traveling forward into hammers "removed" kinetic striker bore.
Results were absolutely as expected 8)
Up late? 8)
Thanks for posting your write up about TM SSG.
Found this, looks like an SSG in a pumper in 2006:
http://www.network54.com/Forum/275684/thread/1160273704/A+hammer+for+knock-open+valve. (http://www.network54.com/Forum/275684/thread/1160273704/A+hammer+for+knock-open+valve.)
Edit: But why in a pumper?
-
Looks like a combination of the SSG and NBH.... Nothing new under the sun !!!
Bob
-
With all the interest in the SSG, various other similar ideas have been brought forward over the past weeks.... The first thing mentioned was using a short, stiff spring, with a gap (negative preload) which I first saw done by Lloyd Sikes a few years back.... It turns out that Harry Fuller used that idea a decade ago in his Excalibre.... While there is a similarity with the SSG, in that there is indeed a gap, without the stop on the guide no preload can occur on the spring, which is the key to the operation of the SSG.... Recently, a photo has surfaced of a hammer made by a "Val" also about a decade ago, which looks like this.... (mentioned in post #722 above)....
(http://i378.photobucket.com/albums/oo221/rsterne/Parts%20for%20Sale/Vals%20Hammer_zpsoe1dhiz4.jpg) (http://s378.photobucket.com/user/rsterne/media/Parts%20for%20Sale/Vals%20Hammer_zpsoe1dhiz4.jpg.html)
The spring guide, as you can see, indeed has a stop on it, so that there is no preload on the hammer when it hits the valve stem, allowing it to rebound and force the plastic leaves apart, "arresting oscillating motion of the hammer after striking the valve".... I have read the thread, and there is only one mention of the stop on the guide, I think it likely that all the interest was in the hammer design, and in fact there was a large drawing, immediately above this photo, that didn't even show the spring.... My guess is that a large part of the effectiveness was due to stopping the spring, and it wasn't even recognized at the time, it was simply necessary for the hammer not to stick inside the tube.... Certainly, there does not appear to be any adjustment for either the preload, or the gap (as used in the SSG concept), nor are either mentioned in the thread about Val's Hammer....
http://www.network54.com/Forum/275684/thread/1160273704/last-1160356195/View+Thread (http://www.network54.com/Forum/275684/thread/1160273704/last-1160356195/View+Thread)
My point is this.... There is nothing new under the sun.... Very little has yet to be "invented".... I was very careful not to claim that I "invented" the SSG, because I knew if I did there would be those who would make it their goal in life to disprove that claim.... My development of the SSG was, however, done independently, from concept (emulating a gas ram with a spring) to reality, in my first application in the Grizzly, last year.... I am delighted that the GTA has provided a venue for the explosive growth and interest in the SSG to occur in this thread.... A GTA member recently used the term "Pioneered the SSG" to describe what I did, and I think that is a very accurate description of what I have done (am doing).... He said....
The word pioneered was chosen for a reason, there are so many inventions that don't have any practical purpose or don't actually function as the inventor intended. Pioneered says, the work was done, (and) it was so successful that it allowed other(s) to follow and benefit.
So far, two individuals have asked my permission to use the SSG concept commercially, which I have freely given, on a non-exclusive basis, with the only request that my contribution to it's development be acknowledged, and they have graciously complied.... I wish them the very best in their implementations of the SSG....
Bob
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Another interesting device has just been compared to the SSG.... The transfer bar used in the Crosman Challenger 2009.... It consists of a rod in a separate housing, located between the hammer and the valve.... I think it's only purpose is to move the hammer back relative to the valve, while transferring the strike, but others disagree.... Certainly Crosman never touted it as an anti-bounce device.... It would appear from the drawing on the Crosman website that it is spring-loaded against the valve stem, and the rear of the rod is impacted by the (adjustable) striker on the hammer.... Page 5 on this webpage....
http://www.crosman.com/pdf/manuals/CH2009%20EVP%20&%20PL%201.pdf?source=pepperjam&publisherId=43737&clickId=1540836582 (http://www.crosman.com/pdf/manuals/CH2009%20EVP%20&%20PL%201.pdf?source=pepperjam&publisherId=43737&clickId=1540836582)
The circlip on the shaft would just be to keep the parts together on assembly, it does not touch the spring, that is the other side of the hammer, as on the PRod (which shares the same hammer/striker assembly).... If anyone has a Challenger, perhaps they can look at it and let us know if the hammer at rest sits against the end of the transfer bar, or is there a gap between the back of the transfer bar and the striker?.... That would be the key to whether or not it has any action similar to the SSG.... I know already there is no spring guide, or stop on such a spring guide, in the Challenger, because I have used numerous Challenger hammers, springs, and RVAs myself.... Another thing that would be good to know is how far back the transfer bar can move while compressing the spring on it, before it hits the housing.... It is possible if that distance is very small (eg. 0.020") that would completely debounce the hammer by absorbing the recoil of the valve stem into the transfer block (assuming it is bolted into the gun) instead of transferring the energy back into the hammer.... This would work in a similar way (though differently applied) to the wishbone in the Hatsans that prevents the hammer from being thrown back against the spring....
It may be just one more way to skin a cat (debounce a hammer), or it may just transfer the hammer strike to the valve.... Either way, it has little to do with the way the SSG works....
Bob
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Will measure when I have the rifle apart next.
Do know that it's just as easy to get poor efficiency with a Challenger set to low speeds, although it disguises itself with shot count.
EXAMPLE:
Didn’t run the efficiency calculator until now. Just took a look at +100 “good” shots and 79 “great” shots and thought to myself “good enough”.
(http://i157.photobucket.com/albums/t50/ribbonstone/2009PCP/4212e08d-0087-419f-afcb-42b9c61875db.jpg) (http://s157.photobucket.com/user/ribbonstone/media/2009PCP/4212e08d-0087-419f-afcb-42b9c61875db.jpg.html)
Running the numbers, it comes out to a disappointing 1.1 FPE/cuin.
So whatever that odd system does, it’s not doing it at that setting.
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I have some numbers here for the "old type" external SSG device on non stock Mrod 5.5 cal.
Gun has modified valve, TP and barrel, Huma reg. set at 1800 psi and SSG installed.
Filled to 3200psi and shooting down to 1400psi, AVG speed with Baracudas 21.14gr is 762fps, AVG power is 27.3FPE for a total of 80 shots! 8)
Efficiency is great for the regulated gun, it turns out 1.44FPE/cuin on the calculator. ;D
(http://s20.postimg.org/d6c3pvjlp/10r.png)
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For some time I have been wondering how effective the SSG would be on a CO2 gun like the Crosman 2260.... I had the opportunity to try that out today.... The testing started out with the gun configured exactly as a stock 2260.... Stock valve, hammer and spring, stock transfer and barrel ports, and a 24" barrel, although the gun did have a Crosman steel breech on it.... I loaded a brand new 12 gr. CO2 cartridge, fired the gun twice to pierce the cartridge, and then shot a string using 18.1 gr. JSB Heavy pellets until the velocity dropped to 300 fps, at which point I stopped.... I fired one shot every 30 seconds, and the temperature was 68*F.... I then repeated the testing using a much lightened hammer that was 50% of the weight of a stock one.... In both cases the stock rear cap was in place, so the preload on the 2260 spring was completely stock.... I then fitted an SSG, using the same spring, with as much preload I could use and still cock the gun with no gap between the end of the guide and the hammer.... I adjusted the gap to 0.020", installed a new cartridge, fired two shots to pierce it, and then fired another string.... The results are shown in the graph below....
(http://i378.photobucket.com/albums/oo221/rsterne/1750%20with%20DPH/2260%20Shot%20Count_zps4gkjbbxf.jpg) (http://s378.photobucket.com/user/rsterne/media/1750%20with%20DPH/2260%20Shot%20Count_zps4gkjbbxf.jpg.html)
There are some interesting things to note.... In stock form, even though I was only shooting every 30 seconds to limit cooling, the velocity declined in a near linear fashion for 30 shots, and then dropped rapidly, with a total of 37 shots above 300 fps.... I calculated the FPE of every shot and added them up, getting a total of 341 FPE from a 12 gr. cartridge.... With the lighter hammer, the initial velocity was lower, but within 15 shots it leveled off, staying within a very narrow ES for another 30 shots before dropping, with a total of 53 shots above 300 fps.... The total FPE from that cartridge was 457 FPE, which is pretty good, and a 34% improvement over stock.... With the light hammer and the SSG, the velocity stabilized quite quickly, and I got over 60 shots before it started to decline.... and the initial decline was not as dramatic.... and I got a total of 78 shots above 300 fps.... over twice as many as stock.... The total FPE from a cartridge with the SSG fitted was 627 FPE, breaking my own previous record of 608 FPE with an 18" barreled 1750.... That represents 84% more energy from a 12 gr. than I got stock....
I am extremely pleased with the huge increase in FPE per 12 gr. CO2 obtained by using the SSG.... This was, additionally, the first attempt using an SSG on a CO2 gun for me, and breaking the 600 FPE mark without tuning was pretty impressive.... I look forward to trying some different settings to see if I can get even more energy from a 12 gr. in the future.... but right off the bat, we know it works great on CO2....
Bob
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Bob,
Outstanding documentation on the Co2 tests ... pretty dang conclusive in my eyes the SSG is a must have item in nearly all Precharged or Co2 type actions where one could be fitted.
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Bob,
Outstanding documentation on the Co2 tests ... pretty dang conclusive in my eyes the SSG is a must have item in nearly all Precharged or Co2 type actions where one could be fitted.
Very much agreed ! this is very impressive stuff.
I spoke with Travis today and ordered one for my .22 mrod.
We also spoke of the expected Co2 guns benefits. he did not have a stock 2240 on hand, so I offered to send him mine. Factory stock (with steel breech) 2240 pistol. It will be going out tomorrow for him to use for testing as he see's fit.
He can keep it for as long as he likes.
I will also be sending him one of my Frakengun 22XX based carbines.
They are both converted to HPA, rear Ninja bottled, regged at 1780-1800psi, heavily modified valves, and 18" barrels.
Currently producing the following numbers:
Chrony tested,(using average speed of 5 shots per each pellets tested)
CPHP ------------------------14.3 gr --------1017 FPS --------- 32.85 FPE
Predator Polymag ----------- 16 gr ----------977 FPS -------- 34.13 FPE
JSB Exact Jumbo Heavy ---- 18.13 gr ------ 946 FPS -------- 35.98 FPE
H&N barracuda Match -------21.30 gr -------909 FPS -------- 39.09 FPE
Skenko Newboy Senior ----- 28.6 gr --------815 FPS -------- 42.19 FPE
I do not know what the current shot count is, but I'd guess somewhere around 30-35 within maybe 4% ES (?) but again, that is just a guess.
I think it will be interesting to see the SSG's effects on a pretty well "hot rodded" 2240 valve too.
then next up,...
we'll see if he wants to develop one for the Rainstorm .30 :o
does anyone care to be a co-signer for the loan I'm going to need to take out ? ;) :o ;D
or do we know if Travis does zero interest financing ? ;D ;D ;D
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Im putting a SSG in a .25 cal Flex tomorrow and will as always post results.
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Here it is in the .30 cal Flex first.
Description: Flex .30 SSG HFP
Notes 1:
Notes 2:
Distance to Chrono(FT): 1.00
Ballistic Coefficient: 1.000
Bullet Weight(gr): 45.00
Temp: 67 °F
BP: 30.26 inHg
# FPS FT-LBS PF
20 888 78.81 39.96
19 887 78.63 39.92
18 888 78.81 39.96
17 892 79.52 40.14
16 892 79.52 40.14
15 897 80.41 40.37
14 900 80.95 40.50
13 898 80.59 40.41
12 887 78.63 39.92
11 894 79.87 40.23
10 898 80.59 40.41
9 894 79.87 40.23
8 895 80.05 40.28
7 892 79.52 40.14
6 898 80.59 40.41
5 896 80.23 40.32
4 893 79.69 40.19
3 893 79.69 40.19
2 893 79.69 40.19
1 891 79.34 40.10
Average: 893.3 FPS
SD: 3.9 FPS
Min: 887 FPS
Max: 900 FPS
Spread: 13 FPS
Shot/sec: 0.0
True MV: 893 FPS
Group Size (in): 0.00
Sent from my iPhone
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be interesting seeing a SSG on an as2250xt based gun
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Here it is in the .30 cal Flex first.
Description: Flex .30 SSG HFP
Notes 1:
Notes 2:
Distance to Chrono(FT): 1.00
Ballistic Coefficient: 1.000
Bullet Weight(gr): 45.00
Temp: 67 °F
BP: 30.26 inHg
# FPS FT-LBS PF
20 888 78.81 39.96
19 887 78.63 39.92
18 888 78.81 39.96
17 892 79.52 40.14
16 892 79.52 40.14
15 897 80.41 40.37
14 900 80.95 40.50
13 898 80.59 40.41
12 887 78.63 39.92
11 894 79.87 40.23
10 898 80.59 40.41
9 894 79.87 40.23
8 895 80.05 40.28
7 892 79.52 40.14
6 898 80.59 40.41
5 896 80.23 40.32
4 893 79.69 40.19
3 893 79.69 40.19
2 893 79.69 40.19
1 891 79.34 40.10
Average: 893.3 FPS
SD: 3.9 FPS
Min: 887 FPS
Max: 900 FPS
Spread: 13 FPS
Shot/sec: 0.0
True MV: 893 FPS
Group Size (in): 0.00
Sent from my iPhone
We need a shootout between this and the 80fpe air ranger. :-)
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Can this thread be set as a "Sticky" or whatever ya call it?
There is a wealth of good information in this thread, and I'd hate to see in get buried over time.
Also I do have one question about this subject, and maybe it's already been asked already.
Why not have the Hammer "linked" to the rod in some way?
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A couple of the designs shown in Post #356 on page 18 have the hammer "linked", or in fact solidly attached to the guide rod.... as long as there is a gap between the SSG or hammer and the valve stem when uncocked, and preload in the hammer spring, the device should work in the same manner.... Having the preload and gap adjustable are good features, but not strictly necessary if those adjustments are developed to do the job in the gun in question....
Bob
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I agree a "sticky" would be a good idea.
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Can this thread be set as a "Sticky" or whatever ya call it?
There is a wealth of good information in this thread, and I'd hate to see in get buried over time.
Also I do have one question about this subject, and maybe it's already been asked already.
Why not have the Hammer "linked" to the rod in some way?
Oldpro Mrod SSG appears to be an example. Rod is threaded into the back of the hammer weight. Adds mass to the weight and nothing comes out the back of the gun.
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Can this thread be set as a "Sticky" or whatever ya call it?
There is a wealth of good information in this thread, and I'd hate to see in get buried over time.
Also I do have one question about this subject, and maybe it's already been asked already.
Why not have the Hammer "linked" to the rod in some way?
Oldpro Mrod SSG appears to be an example. Rod is threaded into the back of the hammer weight. Adds mass to the weight and nothing comes out the back of the gun.
Actually the Mrod has a striker that is screwed into the hammer face and it is unscrewed ( that is a first for me ;) ;D ) and the threads drilled out then the striker is passed through the hammer and the spring with lock nut installed to preload the hammer spring and the rear plug is adjusted to allow .004 free travel from the striker to the valve pin with the rifle cocked
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3-4 votes for sticky....mine was a page or two back.
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Did the Challenger investigation. Had to take it apart to find a slow leak anyway.
The transfer rod system is fixed in place by the front action screw (a much beefier screw than the Disco) and by the middle trigger screw (the one that also holds on the bent steel trigger guard).
The transfer rod is spring loaded forward (memory got that one wrong) so that it does rest on the valve stem.
At rest, the striker will contact the transfer rod.
(http://i157.photobucket.com/albums/t50/ribbonstone/2009PCP/3234e0fc-2cbb-4d8b-b26a-bfe77de8af23.jpg) (http://s157.photobucket.com/user/ribbonstone/media/2009PCP/3234e0fc-2cbb-4d8b-b26a-bfe77de8af23.jpg.html)
Fully cocked (which can vary) will give something like .59’ to .65” of striker travel before contacting the transfer rod. Changing the striker’s dwell adjustment will change that distance (shown above, it’s not quite at max dwell).
(http://i157.photobucket.com/albums/t50/ribbonstone/2009PCP/57a2562c-f6b9-47e3-9f9d-7a0dc34000fb.jpg) (http://s157.photobucket.com/user/ribbonstone/media/2009PCP/57a2562c-f6b9-47e3-9f9d-7a0dc34000fb.jpg.html)
BTW: Think this leak was from just the gauge threads into the gauge block. Tightened the gauge ½ turn (which made it read upside down) and the slow bubbling at the gauge thread stopped (or it slowed past my level of concentration to watch for bubbles).
(http://i157.photobucket.com/albums/t50/ribbonstone/2009PCP/0b3b060e-5c9e-47b4-8a55-8ea56e5ad587.jpg) (http://s157.photobucket.com/user/ribbonstone/media/2009PCP/0b3b060e-5c9e-47b4-8a55-8ea56e5ad587.jpg.html)
Being nearly totally part and put back together again, the sight in was ruined. Started off shooting way to the left, but was quickly (3 5-shot targets) brought back on target.
(http://i157.photobucket.com/albums/t50/ribbonstone/2009PCP/7c22cb07-714b-4af1-a778-3c3167d5f535.jpg) (http://s157.photobucket.com/user/ribbonstone/media/2009PCP/7c22cb07-714b-4af1-a778-3c3167d5f535.jpg.html)
Not really sure how that is supposed to act as a SSG…have proved that it can certainly be adjusted to NOT give great efficiency. But I suppose it does do something.
Personally, I just thought the transfer rod assembly was a way to take up the extra length of the Challenger’s air tube to the rear of the valve(tube is longer, but it’s longer from the valve back rather than adding any volume to the valve forward.
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Ive never shot or owned a Challenger but I find them interesting. I think ill have to hunt one down to play with. They are a nice looking gun in my opinion.
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Just an aside:
I absolutely hate the straight pull bolt system's ball-bearing lock as it is constantly (check the Challenger posts) giving problems with bolt jump-back or self-disassembly.
Other than that (and it's a big "that"), have no complaints about the rifle...but that one complaint is enough.
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Thanks, Ribbonstone, as I thought, there is no separation or decoupling between the valve stem, transfer bar, and striker in the Challenger.... so the suggestion that Crosman were using a device similar to the SSG in 2009 is incorrect.... The transfer bar works as a simple extension of the valve stem, and is spring-loaded against it....
Bob
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Never saw any reason for the transfer rod system other than taking up space that needed to be taken up (the extra length to the rear of the valve to allow the log receiver and odd straight pull bolt).
BTW...in today's pricing (using PA as a guide): Crosman Challenger PCP WITH sights = $610 AA 200T with sights (same sights) $525.
Just saying.
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Ive never shot or owned a Challenger but I find them interesting. I think ill have to hunt one down to play with. They are a nice looking gun in my opinion.
I had one. Loved the stock but as Ribbonstone said, the bolt limits the power you can apply. I wouldn't mind having a disco action with the challenger stock and LW barrel, somewhat like Norm_m is doing.
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So on the challenger there are 2 springs pushing against the hammer. Is that right. I just got one of these for my daughter to shoot in 4-H. So far I am impressed with it. 125 shots 521-555 fps. Shot at all pressures and POI didnt seem to change. One hole accurate for the most part.
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Does the front spring pushing towards the rear and the hammer spring pushing towards the front counteract and resist hammer bounce. Just a thought.
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So on the challenger there are 2 springs pushing against the hammer. Is that right. I just got one of these for my daughter to shoot in 4-H. So far I am impressed with it. 125 shots 521-555 fps. Shot at all pressures and POI didnt seem to change. One hole accurate for the most part.
Wow! I think I was "only" getting 70 out of mine, That's with SSG?
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Can this thread be set as a "Sticky" or whatever ya call it?
There is a wealth of good information in this thread, and I'd hate to see in get buried over time.
Also I do have one question about this subject, and maybe it's already been asked already.
Why not have the Hammer "linked" to the rod in some way?
Oldpro Mrod SSG appears to be an example. Rod is threaded into the back of the hammer weight. Adds mass to the weight and nothing comes out the back of the gun.
Actually the Mrod has a striker that is screwed into the hammer face and it is unscrewed ( that is a first for me ;) ;D ) and the threads drilled out then the striker is passed through the hammer and the spring with lock nut installed to preload the hammer spring and the rear plug is adjusted to allow .004 free travel from the striker to the valve pin with the rifle cocked
Thanks - gives me some idea on how he is making the one for the Disco then too.
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The spring on the transfer bar also pushing towards the front, tending to hold the valve open and increase the dwell.... As such, it would tend to increase the ease of the hammer opening the valve when bouncing.... in exactly the same manner as would installing a lighter valve spring....
Bob
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The spring on the transfer bar also pushing towards the front, tending to hold the valve open and increase the dwell....
Do we know whether or not the transfer bar is actually touching the valve stem when the hammer is not pushing against it?
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Yes it is touching the valve stem all the time, it is spring loaded against it.... Since the valve lift in a Challenger would be very small (~0.060"), I would think it even touches it at full open....
Bob
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Yes it is touching the valve stem all the time, it is spring loaded against it.... Since the valve lift in a Challenger would be very small (~0.060"), I would think it even touches it at full open....
Bob
How do we know that the purpose of the spring on transfer rod is to keep pressure forward on the rod (pressured into the valve stem) and not to keep the transfer rod from moving rearward after the shot? I can't tell where the valve stem ends (with valve being inside the tube and not seem) but it kooks at though the possibility exists that in either a cocked or un-cocked state the transfer bar spring could be in a fully relaxed state. In the pics shown above the spring doesn't appear (to me) that there in any tension on it. Otherwise wouldn't the transfer bar "clip" be closer to the outer piece?
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That transfer section won't quite drop in...doesn't align by about 1/8th the screw hole diameter. A little push, and it aligns. So evidently the plunger is contacting the valve stem, likely by less than 1 pound of spring force.
If it was intended to act as a debouncer/shot count extender, then it is a "fail". Of coruse you get a lot of shots at the factory settings, but keeping to the same strict 4% variation, the efficiency hasn't been any different from rifles without that transfer rod.
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Internal Prod SSG https://youtu.be/081UQGwPClI fully functional and will run strings tomorrow.
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I played around with the Hatsan today, and got the SSG working in it.... sort of.... First of all, here are the changes to the gun.... First the stock....
(http://i378.photobucket.com/albums/oo221/rsterne/Hatsan%20AT44-10/Stock%20Mod_zpsqhleehq4.jpg) (http://s378.photobucket.com/user/rsterne/media/Hatsan%20AT44-10/Stock%20Mod_zpsqhleehq4.jpg.html)
You can see the recess ground in the top of the stock to miss the stop nut on the SSG.... This is a mirror image of the one in the rear plug, posted earlier.... Now the rear plug, with the SSG in place.... The gun is uncocked, all you can see is the stop nut and the O-ring, against the back of the plastic rear plug.... The guide rod passes through the existing hole in the middle of the plug....
(http://i378.photobucket.com/albums/oo221/rsterne/Hatsan%20AT44-10/Rear%20Plug%20Mod_zpspaz18fmk.jpg) (http://s378.photobucket.com/user/rsterne/media/Hatsan%20AT44-10/Rear%20Plug%20Mod_zpspaz18fmk.jpg.html)
You will notice that I also had to grind a recess in the bottom of the safety button to miss the stop nut, as well as the rear plug.... I don't have a photo of the SSG out of the gun at the moment, but here is a view of the top of the tube and you can see the SSG inside.... The spring sits in it's original seat in the front of the rear plug....
(http://i378.photobucket.com/albums/oo221/rsterne/Hatsan%20AT44-10/SSG%20Inside%20Tube_zps7ub6a4on.jpg) (http://s378.photobucket.com/user/rsterne/media/Hatsan%20AT44-10/SSG%20Inside%20Tube_zps7ub6a4on.jpg.html)
It consists of two 1.75" x 0.045" wire springs on a 3/16" guide, with a preload of 1.2" (almost 14 lbs !).... The cocking force peaks at nearly 19 lbs., but of course the side lever makes easy work of that.... Lastly, here is a photo of the gun reassembled, this is the cleanest possible installation, you can't even see the SSG....
(http://i378.photobucket.com/albums/oo221/rsterne/Hatsan%20AT44-10/Hatsan%20After_zpspkedgeps.jpg) (http://s378.photobucket.com/user/rsterne/media/Hatsan%20AT44-10/Hatsan%20After_zpspkedgeps.jpg.html)
When I saw how much preload was on the original tube, I was concerned that I could come up with an SSG that would be able to launch the hammer hard enough to create the 72 FPE the gun was shooting before.... because the original spring preload of 9 turns (nearly 9 lbs.) would have been supplying a lot of the valve dwell.... Well, as it turns out, I was right.... I have only done one trial (and might actually give up on this SSG conversion), the results were a 21 shot string from 180 bar down to 120 bar, with 25.4 gr. JSB Kings from 952-979-941 fps.... That averaged 52.9 FPE, for a total of 1110 FPE from 14 CI x 60 bar = 840 CI of air total, which works out to 1.32 FPE/CI.... The closest comparable string I have with the original hammer spring setup, was with 5 turns of preload, from 171 bar to 120 bar, 16 shots averaging 52.8 FPE at an efficiency of 1.18 FPE/CI.... Both strings had a 4% ES and the same FPE, so they are roughly equivalent.... This means I have gained 31% more shots, at a 12% increase in efficiency.... However, there is no way with these springs in the SSG I will even come close to 72 FPE....
I have the setscrew in the hammer set right to the bottom, and adjusted the gap to a bare minimum (~ 0.020").... There is so much preload on the hammer spring that when cocked it is within about 1/16" of coil bind.... so there is nothing more available without using a stiffer spring.... At this point, I don't think it's worth it.... I will ponder it for a day or two, but this gun is probably going to return to normal.... The one thing I did accomplish, which I never managed before, was over 2 magazines with the JSB Kings at over 950 fps, so it's a decent setup.... just not the 72 FPE monster I know this gun can be....
Bob
Bob,
Did you have any pictures of the SSG you did on the AT-44 out of the gun by chance, or any additional pictures that may be useful? I think I will try and give this a go. I picked up some miscellaneous parts at the hardware store to play with today :D I'm still tossing some ideas around in my head on how to maintain some adjust-ability with an SSG in place that doesn't involve removing the stock.
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As usual with my "wonderful" paint diagrams, try not to laugh... I'm sure there are some flaws with this that I'm not seeing. I can see where some energy will be lost since the spring/bolt aren't moving with the hammer when it strikes the valve. Like I mentioned earlier, my goal is to maintain full adjustment without taking the gun apart. This is the best solution I can come up with right now, while keeping full pre-load adjustment. Hopefully, you guys can see what I mean with the diagram. The grub screw for the pre-load adjustment will be drilled out so the 4mm can move freely through it during cocking/firing. I'm thinking I will smooth down and taper the 4mm allen, except for the section near where it is affixed to the cap head screw to prevent excess friction. My balloon is awaiting your needles :-[
(http://i644.photobucket.com/albums/uu168/tiltedmonkey/HAMMER%205.jpg) (http://s644.photobucket.com/user/tiltedmonkey/media/HAMMER%205.jpg.html)
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Is the "4mm" an allen key?.... sliding through the original preload adjusting setscrew?....
Bob
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Yes, it will be a section of an allen key that is attached to the long cap head screw.
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I think it should work OK.... don't see any reason why not....
Bob
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The question I have is on the preload with SSG mod. If I set the preload very high (but still OK to cock) to begin with and then adjust the gap for desired fps, will I still have a declining string like with traditional tuning or is this a mute point with SSG? I ask this because I want to switch between heavy and light pellets occasionally and keep preload set for heavies tuned to max FPS.
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Is there any benefit to using a lightweight hammer with the SSG mod? or best to just use the hammer that would come with WAR's kit?
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Is there any benefit to using a lightweight hammer with the SSG mod? or best to just use the hammer that would come with WAR's kit?
Loaded Q .... generally use of Lighter than OEM weight hammers is a thing we do in REGULATED actions.
This because as valves operating pressure is lowered, energy required to crack it open become lower as well.
If action in question is NON regulated would stay with OEM hammer or case in point the one WAR provides with there SSG kit.
IMO ...
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Bob and others,
After reading this entire thread a couple of times I would like it if you could explain to me, and perhaps others, how you are calculating the efficiency and what exactly better efficiency means.
Be gentle with me as I am somewhat of a 'newbie' on some of this stuff.
Thanks much,
Carl
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Bob and others,
After reading this entire thread a couple of times I would like it if you could explain to me, and perhaps others, how you are calculating the efficiency and what exactly better efficiency means.
Be gentle with me as I am somewhat of a 'newbie' on some of this stuff.
Thanks much,
Carl
http://calc.sikes.us/1/ (http://calc.sikes.us/1/)
More air ya save ... move shots per fill or on a Co2 cart ;)
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Yeah, plugging your gun's numbers into the Sikes calculator - cylinder volume, start and finish pressures, pellet weight, velocity as measured with a chrony then calculated to get an average - will give you efficiency numbers. Basically the PCP equivalent of gas mileage with a vehicle. The higher the number, the further you're going on a tank, or in this case the more shots you're getting per fill.
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Bob and others,
After reading this entire thread a couple of times I would like it if you could explain to me, and perhaps others, how you are calculating the efficiency and what exactly better efficiency means.
Be gentle with me as I am somewhat of a 'newbie' on some of this stuff.
Thanks much,
Carl
http://calc.sikes.us/1/ (http://calc.sikes.us/1/)
More air ya save ... move shots per fill or on a Co2 cart ;)
thanks for that link!
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The question I have is on the preload with SSG mod. If I set the preload very high (but still OK to cock) to begin with and then adjust the gap for desired fps, will I still have a declining string like with traditional tuning or is this a mute point with SSG? I ask this because I want to switch between heavy and light pellets occasionally and keep preload set for heavies tuned to max FPS.
That is a good question. I would think you could do that, but I don't know that you'll have the range of adjustment as you would changing the pre-load of the spring. I'm not sure about that though. Maybe rsterne or motorhead will answer this one.
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The question I have is on the preload with SSG mod. If I set the preload very high (but still OK to cock) to begin with and then adjust the gap for desired fps, will I still have a declining string like with traditional tuning or is this a mute point with SSG? I ask this because I want to switch between heavy and light pellets occasionally and keep preload set for heavies tuned to max FPS.
That is a good question. I would think you could do that, but I don't know that you'll have the range of adjustment as you would changing the pre-load of the spring. I'm not sure about that though. Maybe rsterne or motorhead will answer this one.
Descending velocity ... pure & simply your over driving the hammer with too much spring energy.
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I think it should work OK.... don't see any reason why not....
Bob
Now I just need to source a 5-6 inch socket cap head screw in the 10-24,10-32 range. I know I can order some, but that doesn't give me instant gratification :( I'll see if I can find some locally, like Fastenal or somewhere like that. I was thinking of securing the section of 4mm allen key to the screw by drilling holes in the head and using a couple of small grub screws. If you guys have a better idea on accomplishing that, or accomplishing what I'm trying to do as shown in my diagram, I'm all ears. Suggestions from smarter people than I are always appreciated!
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The question I have is on the preload with SSG mod. If I set the preload very high (but still OK to cock) to begin with and then adjust the gap for desired fps, will I still have a declining string like with traditional tuning or is this a mute point with SSG? I ask this because I want to switch between heavy and light pellets occasionally and keep preload set for heavies tuned to max FPS.
That is a good question. I would think you could do that, but I don't know that you'll have the range of adjustment as you would changing the pre-load of the spring. I'm not sure about that though. Maybe rsterne or motorhead will answer this one.
Descending velocity ... pure & simply your over driving the hammer with too much spring energy.
So it's the same as traditional tuning because of the declining pressure behind the poppet as you shoot I take it. I think I get it now. Thanks!
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I think it should work OK.... don't see any reason why not....
Bob
Now I just need to source a 5-6 inch socket cap head screw in the 10-24,10-32 range. I know I can order some, but that doesn't give me instant gratification :( I'll see if I can find some locally, like Fastenal or somewhere like that. I was thinking of securing the section of 4mm allen key to the screw by drilling holes in the head and using a couple of small grub screws. If you guys have a better idea on accomplishing that, or accomplishing what I'm trying to do as shown in my diagram, I'm all ears. Suggestions from smarter people than I are always appreciated!
If an M5 cap screw will fit (its a bit larger than a #10) it already has a 4mm socket. What I'd do is just glue the thing in place with either a good epoxy like J B Weld, or even Loctite retaining compound.
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I'm getting close! I was able to locate some 6" 10-24 cap head screws, and got the section of an allen key fitted and secured. I also got the pre-load adjustment screw drilled out(thank you cobalt drill bits). I had to do all this with vice grips, a drill, and a dremel. I think it should hold up just fine though. I ground down the allen key's base, and then cut a slot in the head of the screw. It is secured with a 4-32 set screw which I secured with red locktite, and ground that down flush. As you can see with the pictures below, it all fits in the set screw perfectly, so that should allow me the movement I need. Hopefully, the end result will be a full pre-load adjustment, and gap adjustment without taking anything apart. Now I have to machine the the stock, trigger block holder, and safety for clearance. By machine, I mean dremel :(
(http://i644.photobucket.com/albums/uu168/tiltedmonkey/0226162206.jpg) (http://s644.photobucket.com/user/tiltedmonkey/media/0226162206.jpg.html)
(http://i644.photobucket.com/albums/uu168/tiltedmonkey/0226162208.jpg) (http://s644.photobucket.com/user/tiltedmonkey/media/0226162208.jpg.html)
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Well, for my particular gun, I found most of what Bob said to be completely true. It works okay in the AT-44, but just not worth it if you want any real power. The way the gun is made just doesn't allow the SSG to really shine. Don't get me wrong, I was able to get an efficient tune shooting at 25fpe, and more so at 20fpe. I think I got 60 shots at 25fpe before coming off the reg with a few more usable ones after it came off the reg. I didn't finish the 20fpe string, since I was just wasting pellets and will never use the tune. For a .177 AT-44 you could get a ton of shots I'm sure!
My issue came when I tried to get it up to the 35fpe range, and then my increases in efficiency were minimal at best. With the springs I have on hand, there is no way the gun was going to make it up to the 50+fpe range. Keep in mind, my gun is was already tuned very well in the 30fpe range with an efficiency of 1.37, so in my case, the SSG isn't the best option for where I like my gun shooting. Like I said earlier, I think it would work very well for a .177. I could easily see it getting 80+ shots in the 18-20fpe range! I got to see that the SSG does indeed work, but it was basically a lot of time used for results equal to what I already had. I did manage to maintain pre-load and gap adjustment without taking the gun apart, but it was much more tedious to do so, and I removed it and put it back to the way it was.
If I had more springs to play with, and more patience/time, I could probably get it shooting a little better in my gun, but I'm just going to chalk this one up to a learning experience :)
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You should try it on a 70+ FPE AT-44 in .25 cal.... pretty much a waste of time, unfortunately.... The SSG just isn't compatible with the Hatsan design at those power levels....
Bob
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At least you have lots of parts and tools to play with Bob,lol! My dog is very happy that I'm done trying to make that work now. She got severely neglected over the last two days, because I'm the only person she has to hang out with... At least, I can say I gave it a try. Now if I had a .177, I'd be all over it then.
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http://calc.sikes.us/1/ (http://calc.sikes.us/1/)
Motorhead !
Thank you for the link, great.
wll
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With relevance to short springs, lack of pre-load, lightweight hammers, ballistic hammer phase, and repetitive hammer strikes - with and without relevant (air wasting) hammer bounce.
I hope you find this video of interest.
I made it in 2012 to show how a free flight hammer, driven by a spring tuned without pre-load, can largely defeat repetitive valve opening and hence the air waste from hammer bounce. Frame speed 1000 frames /sec.
The rifle is a standard FX Elite (equivalent single shot FX Royale 500) .25 tuned to shoot at approx 45 fpe for 90 shots.
Please be patient with the 4 hammer strikes at approx (seconds) 04, 35, 1:02, 1:38
The first strike opens the valve for the shot; the other three "bounces" don't seem to have enough energy to produce further significant valve openings.
http://vidmg.photobucket.com/albums/v392/Kyogle/FXElitehammerstrikesvalvebounceVeryslow.mp4 (http://vidmg.photobucket.com/albums/v392/Kyogle/FXElitehammerstrikesvalvebounceVeryslow.mp4)
Approx hammer to valve stem gap.
http://img.photobucket.com/albums/v392/Kyogle/FX%20Elite%20hammer%20not%20touching%20valve%20stem%20free%20flight_zpsbhxlpgq5.jpg (http://img.photobucket.com/albums/v392/Kyogle/FX%20Elite%20hammer%20not%20touching%20valve%20stem%20free%20flight_zpsbhxlpgq5.jpg)
Kind regards, Harry.
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I tried holding my mouse pointer level with the end of the valve stem, and the occlusion of the hole by the hammer appears to pass that point just slightly on the 2nd strike, but not on the subsequent ones.... so I would agree it is not likely wasting much air.... Great video, BTW.... Is the Royale regulated or not.... any idea what the pressure drop was for the 90 shots?....
Bob
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The FX Elite is regulated.
I am remiss in not yet finding the shot string so only have the bare summary figures from previous posts.
There were not many Elites released, less than 40 I read. So there are not many shooters who have actually reported data. Scott DeCapio of Colorado reported this shot string from 3400/240 fill from his FX Elite.
Quote Scott:
" I also ran a string over the chrony. 25.4g JSB's from a 3400psi fill:
1-10: 881,886,888,886,886,885,885,880,880,880
11-20: 882,881,881,880,879,881,878,881,878,884
21-30: 884,881,877,876,885,888,887,881,880,883
31-40: 883,881,881,881,880,876,882,885,882,883
41-50: 885,882,882,881,877,879,882,884,881,879
51-60: 880,886,891,885,881,888,882,884,890,889
61-70: 889,891,894,894,890,897,897,897,891,895
71-80: 893,906,898,899,900,897,902,904,899,906
81-90: 898,901,894,899,902,901,902,899,904,901
91-100: 899,897,902,904,903,901,902,904,905,906
101-110:903,903,906,901,897,899,899,899,899,893
111-120:896,894,889,886,886,883,883,880,877,877
That's 120 shots
HIGH: 906 LOW: 876 EXTREME SPREAD: 30fps
Average: ~885fps for about 44.5fpe ... " End quote
Unfortunately he didn't mention end pressure either (which is not uncommon).
But I can't think that it could have been much under say 120 bar 1740 psi given that his 120th shot's velocity was 877 fps/ 43.38 fpe.
That would give 1.52 fpe/cuin or 10.8 bar-cc/fpe at 44.5 fpe av.
Unfortunately Scott's house was washed away in a big flood high up in Colorado and I guess he lost all his fine rifles.
One day I will repeat my data. It is quite some time since I just ran shot strings (pellet waste at the price here). So will have to wait 'til I am doing some target work with that rifle in .25 cal. Presently it has the .22 ST barrel - I may run a string with it..
As I wrote, I hoped that video may have found some interest; I don't remember others showing anything similar. ... Best regards, Harry.
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I’m sending a special THANK YOU to Bob Sterne for pioneering the DIY SSG. I also want to thank Travis (OldPro) for his work on this too.
Bob, I don’t know which I’m most impressed with, your pioneering or your comments back on page 32 of this thread where said you wanted to put this idea out to the airgunning community to see how it will be developed over the next couple of years.
This is my idea I came up with. My version of the DIY SSG allows me to keep the factory look and to adjust the gap and spring tension separately without taking the gun apart in any way.
(http://i284.photobucket.com/albums/ll14/dkwachob/Forum%20Photos%20Do%20not%20delete/SSG%20Parts%2003%202-28-16_zpsmj553n6q.jpg~original)
The results have been positive as you can see my progress here reading from right to left. The far right spreadsheet (H&N 01) is where I started with a Bstaley O-Ring buffer mod, but wanted to shoot the 21.14gn at 850 fps. The DIY SSG accomplished this for me as you can see in my latest test (H&N 04). I'm getting more shots with a higher FPS and still within a 4% ES.
(http://i284.photobucket.com/albums/ll14/dkwachob/Forum%20Photos%20Do%20not%20delete/SSG%203%20Test%203%202-28-16_zpst9ybxuav.jpg~original)
Thanks again!
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I’m sending a special THANK YOU to Bob Sterne for pioneering the DIY SSG. I also want to thank Travis (OldPro) for his work on this too.
Bob, I don’t know which I’m most impressed with, your pioneering or your comments back on page 32 of this thread where said you wanted to put this idea out to the airgunning community to see how it will be developed over the next couple of years.
This is my idea I came up with. My version of the DIY SSG allows me to keep the factory look and to adjust the gap and spring tension separately without taking the gun apart in any way.
(http://i284.photobucket.com/albums/ll14/dkwachob/Forum%20Photos%20Do%20not%20delete/SSG%20Parts%2003%202-28-16_zpsmj553n6q.jpg)
The results have been positive as you can see my progress here reading from right to left. The far right spreadsheet (H&N 01) is where I started with a Bstaley O-Ring buffer mod, but wanted to shoot the 21.14gn at 850 fps. The DIY SSG accomplished this for me as you can see in my latest test (H&N 04). I'm getting more shots with a higher FPS and still within a 4% ES.
(http://i284.photobucket.com/albums/ll14/dkwachob/Forum%20Photos%20Do%20not%20delete/SSG%203%20Test%203%202-28-16_zpst9ybxuav.jpg)
Thanks again!
Keith
I like your DIY SSG but the order you have the pieces laid out does not seem to be the way it is assembled if I am understanding the concept of the contained SSG. Also the extra hole you drilled and added a screw in the end cap is that to prevent the adjustment nut from turning inside the end cap to set spring tension.
Could you please line the parts up in the correct order of assy or loosely assemble it so we all can see just how you have it put together in its working condition. Is the 1/4 x 20 SS bolt not supposed to go thru the stroke adjuster hole you drilled out in the hammer with the o ring on it before inserting in the hole in the hammer and then the drilled nut, then plastic washer, spring, steel washer, nylock nut and then that assy inserted into the end cap with extra screw loosely snugged on nylock nut to prevent it from turning when adjusting the spring tension but still allow it to move in or out to set free play for hammer.
If that is not the correct sequence of parts please clarify as to what is or if the way they are laid out in the picture is the correct sequence of assembly.
Thanks Mike
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Mike, just pull the bolt and O-ring out of the spring and insert it through the hammer. The rest of the image is in order. I was just trying to keep the image within this forum limits and my cameras range.
" extra screw loosely snugged on nylock nut to prevent it from turning when adjusting the spring tension but still allow it to move in or out to set free play for hammer." Yes that's correct. It sticks through the inside of the end cap about 1/32" which is enough to do the job without interfering with the movement of the nut.
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Keith
Thanks that what I was thinking but just wanted to clarify it since I am going to make a DIY one of my own and like your design a lot.
Mike
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Keith
Thanks that what I was thinking but just wanted to clarify it since I am going to make a DIY one of my own and like your design a lot.
Mike
Mike, drill the set screw hole on top of the end cap as it's being inserted in the air tube. I messed up in not doing that, but it still works fine for me. Also, use something instead of the O-ring on the bolt as I don't know how long it will last. I recommend a thin felt washer or a very thin slice of leather. Just keep it very thin so as not to mess up the gap adjustment over time. Doing this really cuts down on the shot noise a lot, but is also optional. Good luck!
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Keith
Ok I did not look close enough but I see you did drill the set screw hole in the bottom side of the end cap but as long as you Loctite that screw it really would not matter since it is not being adjusted often at all but is just to prevent the nut from turning.
I believe if you use a 90 duro or urethane o ring it will last quite well, but time will tell with it.
Mike
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Oldpro, any update on the Prod? Has anyone made an "internal" clean version for a 22xx? I have two 2260's, I'd like to mess around with. Well, I should say one is a 2400kt, but same thing. I tapped my end cap on my 2400kt the other day to make a diy power adjuster. I noticed from a quick preliminary string, I didn't gain a whole lot of velocity, maybe 20-30 fps, but the report cleaned up. I'm wondering if all the extra preload on the factory spring helped debounce the hammer maybe? Need to run several full strings to find out I reckon.
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"Clean" is subject to interpretation...as would be "internal". ;)
Might be a little biased, but I think this qualifies as both...
http://www.gatewaytoairguns.org/GTA/index.php?topic=102095.msg974811#msg974811 (http://www.gatewaytoairguns.org/GTA/index.php?topic=102095.msg974811#msg974811)
And for a "sorta" QB...
(http://i245.photobucket.com/albums/gg76/gippeto_album/20160313_172230_zpsknvjnifb.jpg) (http://s245.photobucket.com/user/gippeto_album/media/20160313_172230_zpsknvjnifb.jpg.html)
Al
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Very nice, as usual, Al....
Bob
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+1 on that Al. I like it and I would say it qualifies on both requirements of " clean and internal " IMO
Mike
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So it appears that the primary focus most users have for the SSG is more shots at max power and inside a given ES. Also the guns with SSGs appear to be primarily .22 or .25.
I'm trying to set up my 177 marauder for Hunter Field Target. My ideal setup would be a heavy pellet like CPH (10.5g), about 890-900 peak fps with an ES of no more than 20fps. Need 70-80 shots with a nice gradual curve.
Is an SSG appropriate for this tune? or should I look toward a regulator and light weight hammer?
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An SSG device will benefit any caliber as it essentially remove any bounce, it also decreases ES numbers in most guns, since the ssg at its core relies on a "free floating" but tension hammer.
In your application I would consider a Regulator and an SSG. The combination is an absolute dream.
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Paul you can reach your goal with a regulator and SSG and a stock hammer. ;)
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So it appears that the primary focus most users have for the SSG is more shots at max power and inside a given ES. Also the guns with SSGs appear to be primarily .22 or .25.
I'm trying to set up my 177 marauder for Hunter Field Target. My ideal setup would be a heavy pellet like CPH (10.5g), about 890-900 peak fps with an ES of no more than 20fps. Need 70-80 shots with a nice gradual curve.
Is an SSG appropriate for this tune? or should I look toward a regulator and light weight hammer?
Personal .177 M-rod ( set-up for FT work )
LW hammer
Regulated ( Milo74 )
External SSG devise ( own design )
AA 10.3 pellet at @ 910 fps
95 shots under regulation having an ES of 10 fps.
YES VERY DOABLE 8)
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This has gotten out of hand for me…just getting too specialized and the feeling my efforts could be better spend in other areas.
A simple version did improve efficiency to about 1.65 FPE/cuin. But I couldn’t get the .177 test rifle up past 11 foot pounds.
Going back to the non-ssg version only manages 1.35 FPE/cuin but also manages 14.6 foot pounds.
All In all, even as a pump filler, decided to go with the simpler (non _SSG) version and live with the less efficnety version.
Why?
It’s really easier to cycle/cock.
The illustrated/posted version have gotten kind of complicated/specialized.
Couldn’t get it up to “hunting speed” without a really drastic increase in cocking effort.
22 shots at 14.6foot pounds is more useful to me.
Why it worked so well in the .22 version (am keeping the SSg in place on that one) and less than thrilling with the .177 version, I really do not know.
But for the time being, the .22’s SSG stays, the .177’s SSG goes.
(http://i157.photobucket.com/albums/t50/ribbonstone/HiPaC/57f2cb70-38dc-48a1-92b7-925ee7de27d5.jpg) (http://s157.photobucket.com/user/ribbonstone/media/HiPaC/57f2cb70-38dc-48a1-92b7-925ee7de27d5.jpg.html)
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So it appears that the primary focus most users have for the SSG is more shots at max power and inside a given ES. Also the guns with SSGs appear to be primarily .22 or .25.
I'm trying to set up my 177 marauder for Hunter Field Target. My ideal setup would be a heavy pellet like CPH (10.5g), about 890-900 peak fps with an ES of no more than 20fps. Need 70-80 shots with a nice gradual curve.
Is an SSG appropriate for this tune? or should I look toward a regulator and light weight hammer?
Paul,
Check the hole size of the T-port. Even though the Marauder valve has the T-port throttling screw, too large of a T-port will not help you achieve you goal. With the couple of .177 Marauders I have seen, the T-port is large enough for a .22, which is too large for a .177.
A good T-port size for the 18-20 fpe range is .090" Check it with a 3/32" (.093") drill bit. If the shank of the bit wiggles around in the hole, the hole is too big, and your air efficiency, and the flatness of your shot string will suffer.
Lloyd
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Triggerthreat, do you happen to have a picture assembled. I am a little confused with the washer and the .22 o ring. Also with the adjustment hole drilled out and using the lock nut to prevent backing out, how hard is it to adjust under tension with the locknut . No risk of breaking the small flat head or splitting the slot you cut?
I’m sending a special THANK YOU to Bob Sterne for pioneering the DIY SSG. I also want to thank Travis (OldPro) for his work on this too.
Bob, I don’t know which I’m most impressed with, your pioneering or your comments back on page 32 of this thread where said you wanted to put this idea out to the airgunning community to see how it will be developed over the next couple of years.
This is my idea I came up with. My version of the DIY SSG allows me to keep the factory look and to adjust the gap and spring tension separately without taking the gun apart in any way.
(http://i284.photobucket.com/albums/ll14/dkwachob/Forum%20Photos%20Do%20not%20delete/SSG%20Parts%2003%202-28-16_zpsmj553n6q.jpg)
The results have been positive as you can see my progress here reading from right to left. The far right spreadsheet (H&N 01) is where I started with a Bstaley O-Ring buffer mod, but wanted to shoot the 21.14gn at 850 fps. The DIY SSG accomplished this for me as you can see in my latest test (H&N 04). I'm getting more shots with a higher FPS and still within a 4% ES.
(http://i284.photobucket.com/albums/ll14/dkwachob/Forum%20Photos%20Do%20not%20delete/SSG%203%20Test%203%202-28-16_zpst9ybxuav.jpg)
Thanks again!
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Anyone that has done Bob's "original" SSG on a Marauder, did you remove the stroke screw in the hammer? If you did, what did you replace it with?
Cut it off ... Or use a 1/4-28 thread Grub screw with the cup point ground flat for striking poppet stem. Loc-tite in flush with hammer face.
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So it appears that the primary focus most users have for the SSG is more shots at max power and inside a given ES. Also the guns with SSGs appear to be primarily .22 or .25.
I'm trying to set up my 177 marauder for Hunter Field Target. My ideal setup would be a heavy pellet like CPH (10.5g), about 890-900 peak fps with an ES of no more than 20fps. Need 70-80 shots with a nice gradual curve.
Is an SSG appropriate for this tune? or should I look toward a regulator and light weight hammer?
Personal .177 M-rod ( set-up for FT work )
LW hammer
Regulated ( Milo74 )
External SSG devise ( own design )
AA 10.3 pellet at @ 910 fps
95 shots under regulation having an ES of 10 fps.
YES VERY DOABLE 8)
[/quote
Almost there Scott 85 shots so far 930s, and I feel estatic with that almost afraid to keep screwing with things lol!! Who would have thought when the mrod first came out we would be getting shot counts like these. David
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My .177 just has an NBH (and probably a little residual WAR fairy dust), no SSG, and tuned to 880fps (17.5fpe), I'm getting 67 consistent shots within 3%. The last three to round out 70 are still close enough for most shooting.
Still...when the room is quiet and the voices in my head are in conference...I think how nice the gun would shoot if I sent it to Motorhead for the full-bore regulated Motorhead magic touch...
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Triggerthreat, do you happen to have a picture assembled. I am a little confused with the washer and the .22 o ring. Also with the adjustment hole drilled out and using the lock nut to prevent backing out, how hard is it to adjust under tension with the locknut . No risk of breaking the small flat head or splitting the slot you cut? "
I have not had any issues with the slot breaking, but never adjusted with the gun cocked. The new way to adjust (see below) is so simple, fast and easy it takes a lot less shots to adjust to your liking. The gun retains the factory look and you don't have to remove anything to make an adjustment to either setting.
This is my latest version, it completely separates the gap adjustment from the spring adjustment. You can now adjust one without interfering with the other. The old version added a set screw in the end cap. Now the set screw and the Loc-nut are no longer needed.
(http://i284.photobucket.com/albums/ll14/dkwachob/Forum%20Photos%20Do%20not%20delete/DIY%20SSG%2006_zps5ze0b9xl.jpg~original)
I installed an O-ring inside the hammer to lock down the spring. The other end of the spring gets wedged inside the nylon spacers' cone shape. With one end of the spring locked down, the only thing that turns is the spring adjustment when turning the end of the bolt. I have to thank Marauder .22 for his input on this.
(http://i284.photobucket.com/albums/ll14/dkwachob/Forum%20Photos%20Do%20not%20delete/DIY%20SSG%2001_zpsdteupxwc.jpg~original)
I also added a sleeve in the hammer for more surface contact with the bolt to help prevent hammer tilt and improve cocking.
(http://i284.photobucket.com/albums/ll14/dkwachob/Forum%20Photos%20Do%20not%20delete/DIY%20SSG%2004_zps4czzya8l.jpg~original)
The spring is still adjusted with a screwdriver through the gap adjuster set screw.
(http://i284.photobucket.com/albums/ll14/dkwachob/Forum%20Photos%20Do%20not%20delete/DIY%20SSG%2002_zpslk7zjzhu.jpg~original)
The nut on the end of the bolt is securely fastened near the end of the bolt (end of bolt touches gap adjuster). This nut helps center the bolt and prevents the spring adjuster from ever touching the gap adjuster. The nut is optional, but don't let the spring go back too far. The nut will give you a zero reference for the spring adjuster.
(Not pictured) I have drilled out the bolt and installed a nylon bolt in the head to reduce the report. I also installed a leather washer between the bolt and hammer and depinged the air chamber and am enjoying a really quiet report now. No pictures of this yet because I have a new spring coming and have not settled on a final configuration.
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LOL, thanks Triggertreat. I just came back from Ace hardware buying all the nuts and bolts from the picture you had posted earlier. I was going to tackle it this weekend but now the new pictures kind of threw me off again. Where did you get the sleeve and it looks like you drill out the hammer again to fit the sleeve? I guess I will wait for the finished product before doing anything.
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LOL, thanks Triggertreat. I just came back from Ace hardware buying all the nuts and bolts from the picture you had posted earlier. I was going to tackle it this weekend but now the new pictures kind of threw me off again. Where did you get the sleeve and it looks like you drill out the hammer again to fit the sleeve? I guess I will wait for the finished product before doing anything.
LoL, I would go the new route. The 3/8"x3/8" spacer is much easier to do than drilling and taping the end cap. You just tap the spacer for 1/4-20 (no drilling required) then grind half of one end down to a cone shape and leave the surface rough and install the O-ring (1/2 x 5/16 x 3/32). I got the spacer and O-ring at ACE. This method also separates the adjustments too. The old mod works too, but does not separate them.
The sleeve is optional and is one I fabricated from shelving support hardware laying around. It had a 1/4-20 thread I drilled out and the head was much bigger too. You can use any sleeve. I'm still testing it to see if it's beneficial or can I do without it.
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I have now replaced the ACE Hardware spring with a 12.5lb spring I ordered off of Ebay from Tim Hill. This 12.5lb spring is so much better. The cocking issues I was having are gone and it's now very easy to cock.
This is my first attempt at tuning with the 12.5 spring. I broke my trigger and was not able to finish the tune. I want to lower the peak a little to improve the ES spread. It has a nice bell curve, but feel I can do better. I'm waiting on an ordered trigger from Crosman to complete.
This image is a comparison of the ACE spring (H&N 08 blue line) compared to the 12.5 spring (H&N 09). The improved average FPS and low air usage for the same 40 shots is probably the differences between gap settings, but I don't know that for sure. All I did was replace the spring.
(https://image.ibb.co/hiJDPa/SSG_09_12_5lb_02_zps6gehrvkp.jpg)
Here is the tune analyzed for 4% ES:
(https://image.ibb.co/hpqhHv/SSG_09_12_5lb_04_zps5rabrupk.jpg)
Here is the tune analyzed for 30 shots with a little tighter ES and includes the detailed numbers:
(https://image.ibb.co/fKaMAF/SSG_09_12_5lb_01_zpsayvmcdce.jpg)
This is with 21.14gn H&N Match pellets. I plan to lower the peak to around 860 fps to tighten the ES for 40 shots when the new trigger arrives.
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Hey Keith,
I like your shot string analyzer. Where did ya get it?
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;D Ok shot my first string over the chrony 786 to 789fps from 3000 psi fill I have not opened the air restrictor all the way it is still at the factory setting with the screw backed all the way open what can i expect to see for velocity increase the SSG rom WAR is set to his recommended pre set. also installed the WAR NBH so I am seeing 46 FPE as is but I would like to get closer to 900 FPS is that realistic or not? Also like the accuracy from these JSB Match Diablo 33.95 Heavy pellets
Right now I am looking for some advice from the Mavens ;) ;)
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Finalized my internal DIY SSG build. I find this one to be the best setup and really works well. For more details, look me up on the MarauderAirRifle.com forum under 22 cal Internal DIY SSG/FFH thread (22synrodn).
(https://image.ibb.co/hYrVfF/Final_SSG_01.jpg)
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Finalized my internal DIY SSG build. I find this one to be the best setup and really works well. For more details, look me up on the MarauderAirRifle.com forum under 22 cal Internal DIY SSG/FFH thread (22synrodn).
(http://i284.photobucket.com/albums/ll14/dkwachob/Forum%20Photos%20Do%20not%20delete/Final%20SSG%2001_zps6iqwsxaq.jpg)
Keith
How long is the 1/4-20 SS bolt you are using in the SSG. Why did you cut a groove in the nylon washer that fit inside hammer and is it a radial groove for the spring or actually slots to prevent spring from rotating in nylon bushing for adjusting.
I like the idea and execution of design.
Mike
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Finalized my internal DIY SSG build. I find this one to be the best setup and really works well. For more details, look me up on the MarauderAirRifle.com forum under 22 cal Internal DIY SSG/FFH thread (22synrodn).
(https://image.ibb.co/hYrVfF/Final_SSG_01.jpg)
Keith
How long is the 1/4-20 SS bolt you are using in the SSG. Why did you cut a groove in the nylon washer that fit inside hammer and is it a radial groove for the spring or actually slots to prevent spring from rotating in nylon bushing for adjusting.
I like the idea and execution of design.
Mike
Thanks Mike. The bolt is 2.5" long. The grooves were cut in the nylon spacer with the edge of a file so the spring would grip it when adjusting the spring tension. This eliminates the o-ring needed in the previous design and also the steel sleeve. I did bend the end of the spring out a little to ensure it grips good. Works really well. Make the grooves prior to inserting into the hammer because the spacer is a tight fit. Make sure the hole in the spacer has a close tolerance to the bolt. I used a used 1/4" drill bit and checked before inserting it. I used the head of the bolt with a nut on the end to protect it when hammering it in.
(https://image.ibb.co/fPV97v/Final_SSG_02.jpg)
(https://image.ibb.co/ifvdZa/Final_SSG_03.jpg)
I threaded in a nylon bolt into the head of the bolt to reduce the noise of the metal bolt hitting the valve stem. I've shot close to 300 rounds with it and it's holding up very well with no signs of damage.
(https://image.ibb.co/dUuSSv/Final_SSG_04.jpg)
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Keith
I like a lot and of all the different versions I have seen in this thread I like yours the best for the Mrods and I shoot field target with my 177 mrod amnd this is the perfect mod to lower my 20 fps spread and increase my shot count as well.
I think I can get under 10 fps spread and over 50 shots per fill easy since I have it set now at 20 fps spread and 45 shots per fill from 3000 psi down to 2200 psi .
Got a big match in June and will have it installed and tuned by then for sure.
Thanks Mike
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If you can get sub-10fps across a flat 50-shot string, that would be a great option to the expense of a regulator. My NBH Mrod .177 is shooting 17fpe, 67 shots within 3% (about 25fps).
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Keith
I like a lot and of all the different versions I have seen in this thread I like yours the best for the Mrods and I shoot field target with my 177 mrod amnd this is the perfect mod to lower my 20 fps spread and increase my shot count as well.
I think I can get under 10 fps spread and over 50 shots per fill easy since I have it set now at 20 fps spread and 45 shots per fill from 3000 psi down to 2200 psi .
Got a big match in June and will have it installed and tuned by then for sure.
Thanks Mike
Thanks Mike! Sorry to have put you and others through all the different versions, but I wanted to test all the ideas I had in my head some I never posted about. The ACE spring, although it worked, was causing me grief and I did not want any o-rings to worry about. This version should hold up for a very long time.
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If you can get sub-10fps across a flat 50-shot string, that would be a great option to the expense of a regulator. My NBH Mrod .177 is shooting 17fpe, 67 shots within 3% (about 25fps).
Sub-10fps could be possible, but I want make any claims. I tune for hunting and the higher fps you go the less likely you'll get sub-10 fps, but still should be very decent. With a low powered tune you just may be able to if everything in the gun is slick and consistent.
I just finished putting triple oil on my deck (shooting platform) and once it is ready for traffic and I get a break, I'll be able to do a proper tune and will post on how well it does. Preliminary test looks real good. My goal is 30-40 shots with a 850 fps average and as low an ES as it will give me. Stay tuned...
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If you can get sub-10fps across a flat 50-shot string, that would be a great option to the expense of a regulator. My NBH Mrod .177 is shooting 17fpe, 67 shots within 3% (about 25fps).
Mark
Right now I am shooting JSB 10.34s at 880 to 900 fps/18.5 fpe for 45 shots with every once in a while if the wind is calm I can get another 5 to hit the same POI. I think the SSG will allow me to tighten the spread up at least 10 fps and likely go over the 50 shots I am after and if I get close to the 67 you are getting even better.
Our monthly matches are 48 shots so wanting to shoot a match without having to fill and we have a sanctioned match in June that will be 60 shots per day so if I can get that on one fill as well would be a big plus indeed.
Does sound promising.
Mike
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If you can get sub-10fps across a flat 50-shot string, that would be a great option to the expense of a regulator. My NBH Mrod .177 is shooting 17fpe, 67 shots within 3% (about 25fps).
Sub-10fps could be possible, but I want make any claims. I tune for hunting and the higher fps you go the less likely you'll get sub-10 fps, but still should be very decent. With a low powered tune you just may be able to if everything in the gun is slick and consistent.
I just finished putting triple oil on my deck (shooting platform) and once it is ready for traffic and I get a break, I'll be able to do a proper tune and will post on how well it does. Preliminary test looks real good. My goal is 30-40 shots with a 850 fps average and as low an ES as it will give me. Stay tuned...
Keith
I have my 22 and 25 for hunting so my 177 is for field target work so I am after average of 890 fps with as close to that for a 60 shot string at minimum and more if better using JSB 10.34s. I am tuned for 880 to 900 fps now with it for 45 good shots and 50 on good days so I think the SSG will give me that extra ten plus shots as well as tighten up the spread.
Got the parts list ready to go shopping tomorrow so will soon see how it does.
Mike
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Keith
I like a lot and of all the different versions I have seen in this thread I like yours the best for the Mrods and I shoot field target with my 177 mrod amnd this is the perfect mod to lower my 20 fps spread and increase my shot count as well.
I think I can get under 10 fps spread and over 50 shots per fill easy since I have it set now at 20 fps spread and 45 shots per fill from 3000 psi down to 2200 psi .
Got a big match in June and will have it installed and tuned by then for sure.
Thanks Mike
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If you can get sub-10fps across a flat 50-shot string, that would be a great option to the expense of a regulator. My NBH Mrod .177 is shooting 17fpe, 67 shots within 3% (about 25fps).
Sub-10fps could be possible, but I want make any claims. I tune for hunting and the higher fps you go the less likely you'll get sub-10 fps, but still should be very decent. With a low powered tune you just may be able to if everything in the gun is slick and consistent.
I just finished putting triple oil on my deck (shooting platform) and once it is ready for traffic and I get a break, I'll be able to do a proper tune and will post on how well it does. Preliminary test looks real good. My goal is 30-40 shots with a 850 fps average and as low an ES as it will give me. Stay tuned...
Keith
I have my 22 and 25 for hunting so my 177 is for field target work so I am after average of 890 fps with as close to that for a 60 shot string at minimum and more if better using JSB 10.34s. I am tuned for 880 to 900 fps now with it for 45 good shots and 50 on good days so I think the SSG will give me that extra ten plus shots as well as tighten up the spread.
Got the parts list ready to go shopping tomorrow so will soon see how it does.
Mike
Mike, that's some impressive numbers for a guy like me. I only shoot the H&N Barracuda Match 21.14gn pellets. I would run out of air way before I hit those numbers and shot count Lol. If your gun is shooting efficiently the SSG wont do to much, but if not the SSG will expose the inefficiency. Good luck and would love to see a post of your before and after results. You should hear a reduction in the report with the SSG if your wasting air now.
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Trigger fixed and new tune done. I lowered the peak down to 860 fps as mentioned previously. I was able to gain more shots within 4% ES. This is the comparison from the last string H&N 09:
(https://image.ibb.co/dyYS0F/SSG_Final_10_06_zpslscesrzk.jpg)
This is an analysis with 40 shots. I like the 2.32% ES for 40 shots with a 2900 psi fill better:
(https://image.ibb.co/fqz6ua/SSG_Final_10_02_zpsh1zujxlt.jpg)
(https://image.ibb.co/dphn0F/SSG_Final_10_03_zpsz2cn8zgx.jpg)
And here is the string analyzed for 4%:
(https://image.ibb.co/gDZvnv/SSG_Final_10_01_zpsxeh0l9sc.jpg)
No sub-10, but works for me. This was the first tune with the new and finalized SSG build which includes a new hammer and parts. I'm hopeful that after a break in period it may even get better.
Just to be clear, this is the DIY SSG build that was used for these strings:
(https://image.ibb.co/hYrVfF/Final_SSG_01.jpg)
(https://image.ibb.co/ifvdZa/Final_SSG_03.jpg)
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Keith
That 20 fps spread in test 10 is nothing to complain about and 40 shots is doing real good in 22 caliber as you have to remember you are using at least 1/3 more air per shot than my 177 is so I think you have it doing very well and would be more than happy with those numbers. You may want play with the air screw adjustment to see if you can tighten the spread up a bit closer and still stay in the velocity range your at and should gain a few more shots as well since you will be using a bit les air per shot.
It only takes an 1/8 of a turn on the air screw to make a big difference and wide open is five turns out from fully seated lightly so you have a range of five turns from fully closed to fully open to play with. My 177 is at 1 7/8 turn out from fully seated and five turns in on hammer spring preload with the stroke adjustment at fully CCW or maximum hammer travel.
Mike
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Thanks Mike, I do have the VMS at full open (6 turns out). I also have the TP drilled out to 0.141. If I put the stock TP back in that might do the trick as well, but will try to close the VMS down some without lowering the peak.
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Keith
The nice thing is you can always go back to where you have it now so it does not hurt to adjust and see what you get. You say you drilled out the TP port to .141" and that's the same size as a 25 caliber TP port and if so did you open the port in the valve itself to the same size and the barrel as well. If not then you are just creating a expansion chamber of sorts in the TP port as it still get choked at the barrel.
The 177s and 22 share the same TP sizes as well as valves and barrel ports so the bigger TP port could be creating some turbulence and issues in air flow. I don't think it would be enough to make much difference though and you should see a difference with the VMS adjustments.
Mike
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Keith
The nice thing is you can always go back to where you have it now so it does not hurt to adjust and see what you get. You say you drilled out the TP port to .141" and that's the same size as a 25 caliber TP port and if so did you open the port in the valve itself to the same size and the barrel as well. If not then you are just creating a expansion chamber of sorts in the TP port as it still get choked at the barrel.
The 177s and 22 share the same TP sizes as well as valves and barrel ports so the bigger TP port could be creating some turbulence and issues in air flow. I don't think it would be enough to make much difference though and you should see a difference with the VMS adjustments.
Mike
No I only drilled the sleeve. The valve and barrel remain stock. I was thinking the sleeve was causing some restriction itself based on some forum reading. I ordered a spare sleeve to drill so I still have the stock sleeve. I've thought about the turbulence issue but wasn't sure. Thanks for the input.
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Keith
I would play with the VMS first since it an easy adjustment and especially if you clearance the stock to facilitate access without having to remove the action from the stock. I have done my two 177s and 25 that way so its just adjust and shoot with action still in the stock.
Just use a sharpie and mark where the VMS hole is in relation to the action in the stock and then use a round file or dremel sanding drum to make a groove to gain access or if you prefer you can drill a hole at an angle to intersect with the VMS screw. It makes adjustments a snap and if that does not tighten the spread up some then try the stock TP port.
Mike
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Keith
I would play with the VMS first since it an easy adjustment and especially if you clearance the stock to facilitate access without having to remove the action from the stock. I have done my two 177s and 25 that way so its just adjust and shoot with action still in the stock.
Just use a sharpie and mark where the VMS hole is in relation to the action in the stock and then use a round file or dremel sanding drum to make a groove to gain access or if you prefer you can drill a hole at an angle to intersect with the VMS screw. It makes adjustments a snap and if that does not tighten the spread up some then try the stock TP port.
Mike
Just to be clear, I'm going to fill back to my peak fps then start turning the VMS in until the fps starts to drop. Then I'll back off to my existing peak fps. I'll essentially keep my same tune but increase the shot count. This is what I believe you're saying.
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Hey Keith,
A lot of guys are looking at this for their 177s and 22s to smooth out for FT. I'm more at a point similar to yours, higher power hunting.
Do you feel the work and parts are warranted for a 25? Enough benefit to make it worth while?
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Hey Keith,
A lot of guys are looking at this for their 177s and 22s to smooth out for FT. I'm more at a point similar to yours, higher power hunting.
Do you feel the work and parts are warranted for a 25? Enough benefit to make it worth while?
IMHO, yes. It's cheap and easy. You may have to adjust the spring rating for the 25s to a 14lb, but testing for your desired tune will determine this.
The main benefit of the SSG is preventing wasted air per shot and lowering the ES over traditional tuning. Since your not wasting as much air per shot, the shot noise is reduced too. The biggest con is increased cocking effort, but if all is smooth, it's not by much and very doable.
With the 21.1gn, I used to only get 25 shots at an average of 828 fps with the Bstaley BHB O-ring mod and now I've almost doubled the shot count with an average of 850 fps. I'm working on lowering my current ES of 2.32% for 40 shots as I was getting 1.92% with the O-rings. I have a new hammer that I have not polished yet and have not closed off the VMS yet so my ES should improve in the future along with shot count. The report has been reduced too.
When drilling the hammer, I recommend to start drilling from the inside slowly so you can file smooth the exterior hammer easier than trying to file the inside of the hammer. The hole must not have any burrs to grab the bolt or cocking and ES will suffer. Don't try to use the bit to smooth out the hole. You want the hole to have a close tolerance to the bolt. The same goes for the nylon sleeve. They both should slide freely on the bolt though.
Make sure you check the bolt at the store on a flat steel shelf. I've found some that were off a little and not completely round or were slightly bent. I sand the bolt with 320 grit to make sure the surface is baby smooth.
The best results come from a hammer that slides very smooth within the air tube and slides on the bolt very smooth as well. Make sure the bolt, spring, hammer and air tube are extremely clean and no lube is present. You may benefit from some dry lube but I have not tried that. If the air tube is not slick, you could benefit from sanding it with 320 grit using a large wood dowel or using a 1" ball hone with 320 grit or finer.
The SSG benefits will vary depending on how well your tune is now. A poorly tuned gun will benefit the most and a well tuned gun will benefit the least. All should see an increase in shot count to some degree.
I like the ease of tuning and SSG over the traditional method. It's simple and saves on pellets. To tune an SSG, set a gap around .020-.035". To set the gap, remove the trigger assembly so you can insert a pre-measured object thru the trigger slot. Fill to the middle of your desired psi. Start aiming for your peak fps using the spring tension. Refill back to your mid-point psi after several shots to maintain mid-point psi until you achieve your peak fps. Fill to desired max psi and run a string.
You can adjust the gap to fine tune the fps but don't close off the gap, more is better. Too much gap will cause you to have to increase spring tension and cause unnecessary cocking effort.
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Keith
I would play with the VMS first since it an easy adjustment and especially if you clearance the stock to facilitate access without having to remove the action from the stock. I have done my two 177s and 25 that way so its just adjust and shoot with action still in the stock.
Just use a sharpie and mark where the VMS hole is in relation to the action in the stock and then use a round file or dremel sanding drum to make a groove to gain access or if you prefer you can drill a hole at an angle to intersect with the VMS screw. It makes adjustments a snap and if that does not tighten the spread up some then try the stock TP port.
Mike
Just to be clear, I'm going to fill back to my peak fps then start turning the VMS in until the fps starts to drop. Then I'll back off to my existing peak fps. I'll essentially keep my same tune but increase the shot count. This is what I believe you're saying.
Keith
Yes you are correct in the way you would adjust the VMS by filling to your peak fps then slowly start to close off the VMS till you see a fps drop and once you see that then open the VMS back to the point where you had no fps drop and that will be the point of lowest air usage giving the highest shot count at your desired fps.
So same tune only gain a few more shots from same fill pressure since less air will be used per shot.
Mike
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Ok Mike, I closed down the VMS to the peak and got better results. I also went back to the stock TP sleeve and replaced the bent 1/4-20 bolt too.
The .22 synrod gun is completely stock except for the internal DIY SSG with 12.5lb spring. I did drill out the air stripper holes bigger and removed the lawyer spring, but its stock everywhere else.
Here are the results:
50 shots at 4%
(https://image.ibb.co/cyu0LF/SSG_11_02_zpsadutuopa.jpg)
40 shots at 1.65%
(https://image.ibb.co/bKcWSv/SSG_11_01_zpsvb1dcz6h.jpg)(https://image.ibb.co/iTiufF/SSG_11_03_zpssjqklmxz.jpg)
I'm happy with the smooth, consistent string with a much lower ES and SD compared to the previous H&N 10 40 shot string I posted earlier.
As far as the sub-10 challenge, here is the string analyzed for sub-10:
(https://image.ibb.co/kpj0LF/SSG_11_Sub_10_01_zpsh10njxmj.jpg)
(https://image.ibb.co/djfqLF/SSG_11_Sub_10_02_zpsdrqihxsd.jpg)
The internal DIY SSG I built and posted at the bottom of page 41 is what I used for this test. No changes were made to it. It's clearly worth the less than $15 in parts if you ask me. I'm just going to enjoy it for a good while. If I get bored, I'll get a HF barrel from Jim for something new to try.
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Posted my disco SSG setup in the Disco thread here...
http://www.gatewaytoairguns.org/GTA/index.php?topic=104863.new#new (http://www.gatewaytoairguns.org/GTA/index.php?topic=104863.new#new)
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Keith
I would say you have it tuned about as close as you will get and increased total usable shot count of 50 with still a respectable 4% ES and kept the same 40 shots at an even better 1.65 ES after closing off the VMS and reinstalling the stock TP port so you see a bigger port is not always the best for consistency and shot count.
If all out power is the goal then yes bigger is better but at the cost of efficiency and shot count so its always a compromise in what the end goals is we are after.
Glad you have it where you are happy so now its time to enjoy shooting it and learn its holds at different distances.
Mike
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Question for Bob Sterne and other experts
And finally Is better regulated 1CC / FPE + SSG or only SSG? :-\
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1cc / FPE is what I recommend for the plenum size in a regulated PCP, and it has nothing to do with whether or not you use an SSG.... Plenum volume is important to prevent the pressure from dropping too much during the shot, because the regulator cannot top up the pressure fast enough to keep a constant (or even near constant) pressure in the valve.... If you are putting a regulator inside the reservoir on a previously unregulated PCP, you may find that 1/2cc / FPE may be better, so that you don't lose as much of the HPA storage volume upstream of the regulator.... You will have to increase the regulator setpoint by about 10% to make up for the smaller volume in the plenum, but the overall shot count may be better with the smaller plenum....
Bob
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New F.A.M.E mod by 22synrodn/triggertreat:
In my view, the biggest problem with the mechanics of the Marauder and other similar guns is hammer drag. I’ve been trying to find a better way to limit this drag in my DIY SSG and have found a simple, DIY way to do this and have decided to share my idea with others.
I introduce to you the F.A.M.E mod which stands for Friction Assist Marauder Enhancement.
My idea lifts the rear of the hammer up and off the air tube which drastically reduces the friction/drag between the two. I find my strings are more uniform and the cocking effort much easier and smoother. Also dirt and dust does not affect the hammer nearly as much or as often. My ES and SD numbers have dropped a considerable amount as well.
You can hone the air tube and polish the hammer but still can’t eliminate as much drag as this mod can. The washer sliding on the top of the air tube has far less friction than the hammer to air tube friction. The 1/4" tubing keeps the hammer centered and off the sides of the metal slot further reducing drag.
Here is a comparison of two very similar tunes with and without the mod and shows how much more uniform the mod makes the string:
(https://image.ibb.co/dALT2v/FAME_Mod_6_10_16_07_zpsrzsbcegp.jpg)
Here is a top view of the F.A.M.E mod installed in my Internal DIY SSG setup. I’ve been using this mod on and off for quite some time now and the differences are very evident to me. So much so that I don’t want to tune without it. The nylon spacer on the end of the bolt is not part of the F.A.M.E mod but is another mod I added to the DIY SSG to reduce rebound noise from the bolt hitting the gap adjuster.
(https://image.ibb.co/dEyWNv/FAME_Mod_6_10_16_01_zpsjh0eyywt.jpg)
Here is more details and the parts needed to do the mod:
(https://image.ibb.co/gW3bpa/FAME_Mod_6_10_16_02_zpsrpc3knbw.jpg)
Here is the mod to the breech needed to clear space for the washer to slide. You only need to remove just enough of the slot to allow for the thickness and width of the washer used.
(https://image.ibb.co/dxwqFF/FAME_Mod_6_10_16_09_zpscvxpflxf.jpg)
If you’re just curious is to how much drag reduction this will give you, you can do a quick test by installing the 1/4” tubing and washer to the hammer lug, tuning it correctly and running your hammer back and forth to feel the difference it makes before trimming the breech. I think you will be pleasantly surprised at the difference as I was when testing it for the first time.
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New F.A.M.E mod by 22synrodn/triggertreat:
In my view, the biggest problem with the mechanics of the Marauder and other similar guns is hammer drag. I’ve been trying to find a better way to limit this drag in my DIY SSG and have found a simple, DIY way to do this and have decided to share my idea with others.
I introduce to you the F.A.M.E mod which stands for Friction Assist Marauder Enhancement.
My idea lifts the rear of the hammer up and off the air tube which drastically reduces the friction/drag between the two. I find my strings are more uniform and the cocking effort much easier and smoother. Also dirt and dust does not affect the hammer nearly as much or as often. My ES and SD numbers have dropped a considerable amount as well.
You can hone the air tube and polish the hammer but still can’t eliminate as much drag as this mod can. The washer sliding on the top of the air tube has far less friction than the hammer to air tube friction. The 1/4" tubing keeps the hammer centered and off the sides of the metal slot further reducing drag.
Here is a comparison of two very similar tunes with and without the mod and shows how much more uniform the mod makes the string:
(http://i284.photobucket.com/albums/ll14/dkwachob/Forum%20Photos%20Do%20not%20delete/FAME%20Mod%206-10-16%2007_zpsrzsbcegp.jpg)
Here is a top view of the F.A.M.E mod installed in my Internal DIY SSG setup. I’ve been using this mod on and off for quite some time now and the differences are very evident to me. So much so that I don’t want to tune without it. The nylon spacer on the end of the bolt is not part of the F.A.M.E mod but is another mod I added to the DIY SSG to reduce rebound noise from the bolt hitting the gap adjuster.
(http://i284.photobucket.com/albums/ll14/dkwachob/Forum%20Photos%20Do%20not%20delete/FAME%20Mod%206-10-16%2001_zpsjh0eyywt.jpg)
Here is more details and the parts needed to do the mod:
(http://i284.photobucket.com/albums/ll14/dkwachob/Forum%20Photos%20Do%20not%20delete/FAME%20Mod%206-10-16%2002_zpsrpc3knbw.jpg)
Here is the mod to the breech needed to clear space for the washer to slide. Although it works just fine, I butchered mine and look forward to a redo when my new breech arrives in a few days. You only need to remove just enough of the slot to allow for the thickness and width of the washer used.
(http://i284.photobucket.com/albums/ll14/dkwachob/Forum%20Photos%20Do%20not%20delete/FAME%20Mod%206-10-16%2008_zpseozxxkea.jpg)
If you’re just curious is to how much drag reduction this will give you, you can do a quick test by installing the 1/4” tubing and washer to the hammer lug, tuning it correctly and running your hammer back and forth to feel the difference it makes before trimming the breech. I think you will be pleasantly surprised at the difference as I was when testing it for the first time.
Interesting idea.
I had that very problem...(rear bottom of hammer galling aginst the main tube in my .25).
I ended up after lots of work on the tube and OEM hammer, just making a LW hammer. Glad I did....(getting a nice shot count and low ES).
That seems like it would be a great way to combat the problem, nice work.
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Interesting mod.... Certainly answers the question about what is causing the zig-zag pattern in shot strings.... it's friction, changing the hammer velocity a whisker....
Bob
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Yes Mike (PBguns), you want have any issues with galling with this mod as it eliminates that issue. Your comments also brings up something else I did not mention about this mod which is, for those power hungry shooters, you can increase the spring rating and still keep a decent and smooth cocking effort.
Bob (rsterne), it does smooth out the string with not having the varying resistance on the hammer slide. I really enjoy tuning with it and can't wait to tune my new Jim Gaska HF barrel with it and the DIY SSG combo. Pushing pellets through the HF barrel, I can tell it's going to be awesome, but really wanted your barrel after reading about it. I didn't know how to order it. Thanks again for pioneering the SSG! I don't see myself shooting the Marauder without it and the F.A.M.E. mod currently.
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Breech modification needed for new F.A.M.E mod.
(https://image.ibb.co/dxwqFF/FAME_Mod_6_10_16_09_zpscvxpflxf.jpg)
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I think this is a marvelous idea... The only change I can think of is to swap out the steel washer for a brass or even bronze washer.... The lubricity (is that a word???) of brass or bronze is far better then steel which should smooth it out even more and being the brass is softer only the washer should wear instead of both the washer and tube causing problems further on down the line....
I don't have time to test it out right now but you can bet I will very soon!!! Honestly you should make a separate post for this as it deserves its own thread
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I think this is a marvelous idea... The only change I can think of is to swap out the steel washer for a brass or even bronze washer.... The lubricity (is that a word???) of brass or bronze is far better then steel which should smooth it out even more and being the brass is softer only the washer should wear instead of both the washer and tube causing problems further on down the line....
I don't have time to test it out right now but you can bet I will very soon!!! Honestly you should make a separate post for this as it deserves its own thread
Thanks it does work well. I had someone else recommending those two metals instead on another forum. Might just have to try those out. The steel has worked well and slides really smooth and I haven't seen any wear after 1000 shots, but the slicker the better.
Maybe I should create another separate post for this one because it will work on other guns like the Prod or discovery I'm sure. I just put it here to go along with the DIY SSG I created. Thanks again and let me know what you think if you try it.
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I'm wondering if the "Old school buttons" sold by Jim Maccari, applied to the hammer, would do the trick without modifying the receiver. I have some I bought years ago when trying to get a Tech Force springer to shoot well. Maybe I'll dig them out and give it a try.
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I'm wondering if the "Old school buttons" sold by Jim Maccari, applied to the hammer, would do the trick without modifying the receiver. I have some I bought years ago when trying to get a Tech Force springer to shoot well. Maybe I'll dig them out and give it a try.
Not a bad idea if you could get the correct fit. I've played around with grilling foil with Teflon and thin plastic too, but just briefly. It's a tight fit. The F.A.M.E. mod is really working well. Here's my latest hunting tune with it and the DIY SSG:
(https://image.ibb.co/gv5bSv/4th_SSG_F_A_M_E_HF_Barrel_Test_01_zpswrbikzkz.jpg)
(https://image.ibb.co/hdfAnv/4th_SSG_F_A_M_E_HF_Barrel_Test_02_zpsvrn0kfan.jpg)
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Here is Steve in NC's excuse on the Yellow for changing the name of his SSG to an FFH.... He is reinterpreting what transpired....
http://www.network54.com/Forum/79537/message/1468510266/A+quick+comment+on+the+terms+%26quot%3BSSG%26quot%3B+and+%26quot%3BFFH.%26quot%3B++In+late+January+of+this+year... (http://www.network54.com/Forum/79537/message/1468510266/A+quick+comment+on+the+terms+%26quot%3BSSG%26quot%3B+and+%26quot%3BFFH.%26quot%3B++In+late+January+of+this+year...)
In actual fact, I contacted him regarding the SSG only to request that since he was making a commercial version, and did so without first having the courtesy to ask my permission (which would have been freely given), that he at least continue to acknowledge my pioneering of the idea.... He originally recognized that, but once it went commercial, he no longer even mentioned me.... Never did I ask him not to use the term SSG, I only asked him to continue to acknowledge where he got the concept.... He had already changed the name of his product to the FFH before I ever contacted him.... I would assume so that he could justify ignoring my development of the concept....
There is no question where he got the idea, he freely admitted it.... He has recently begun to mention me again, I have no idea way, perhaps he is getting flack (or feeling guilty) for not recognizing my contribution in developing the SSG.... However, it is unacceptable to try to rewrite history to suit himself, IMO.... I could care less what he calls his commercial version.... but IMO, just changing the name doesn't erase where he got the idea from.... BTW, I never asked for a dime.... and I never implied in any way that I had a copyright over the idea, or the name SSG, or even that I invented it.... All I asked for was recognition for developing the idea into a useful method for increasing the efficiency of PCPs.... I guess this may be his way of doing that, while trying to explain away the name change to FFH.... ::)
Bob
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Imagine that....not the first time.
GREAT job and contribution Bob.
Too bad some folks can't give the proper respect or credit for other's contributions!!!!
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Wow guys he's always had ba$$s for that sort of thing, Bob keep up the GREAT stuff that you put out for us.
Bob The other one
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Yup Bob,
So much for the Honor system :P ...... or Steve's honoring the Chinese system.
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Guys, I don't want to turn this into bashing Steve, or a love-fest for me.... :-[
I simply want to set the record straight about what transpired between Steve and I, and not let him rewrite it to suit himself.... Let's drop this, OK?.... It is what it is....
Bob
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(I see Bob posted a caution just before I entered the below post... but I don't think I'm bashing Steve really, just saying improvement in communication would be useful all around. So I'll leave it as I wrote it.)
Seems to me quite a few folks in forums have very thin skins when it comes to discussing their innovations and contributions. Just last night I was searching for a short length of .30" barrel towards an eventual bigbore PCP pistol I'm considering building... and ran across a six page discussion on CAF where 'Whitewolf' goes pretty much apepoo on Bob for not intuiting a big pile of stuff about his posts. Like rsterne is some sort of psychic. It gets weird sometimes, as people (especially those with weak communications skills) become defensive and even aggressive about being understood but don't bother to communicate clearly. Steve in NC is much of the time a perfectly civil fellow, generous even. But I've witnessed him behaving very badly in several contexts looking back through several years of forum posts, especially when he seems to feel the need to defend his originality or authorship around airgun innovation. In this particular case, one could easily get the impression if only reading his posts and ads on the Yellow that the 'FFH' was entirely his own idea. This lame half-excuse fiction he's dreamed up is just digging the hole deeper. To what end? There is nothing to be gained by separating himself from rsterne's work. Oldpro makes that obvious, as he gives glcredit where it's due and is selling SSG setups just fine. The difference seems mostly to come down to insecurity. A confident workman doesn't hesitate to share credit for good work.
On a different subject, my most recent SSG work netted a huge efficiency increase for a 2260 carbine with an 18" barrel. The thing was shooting alright on HPA with an SSG, getting 1.56fpe/ci for 25 shots averaging 17.5fpe. But I wanted it quieter, for nearby shots on squirrels, and it didn't have to be quite that powerful for the 10 to 15 metres most of my shots are. So I dumbed it down to just 600fps with 18.13gr JSB and played with the SSG more. Finally found that by further shortening my guide rod and the delrin spring tension adjuster both by 3/4" (about 3.5" guide rod remaining) while retaining the same 4" or so of 1mm spring (compressed to 2.5" on the guide rod), the big increase in preload enabled moving the rod back a bit for 14.5fpe and a dramatic reduction in air waste.
The report now is extremely quiet. Shooting with no pellet becomes a lot louder, so the pellet is soaking up most of the energy of this shorter, sharper impact on the valve. A single O-ring (bstaley style) helps reduce dwell, further limiting air waste. Efficiency over 25 shots at 14.5fpe, from a fill to just 1,200psi, is now 1.89fpe/ci. I love it. Pumping up to 1,200psi is a breeze, and at such low pressure my valve reinforcement is vast overkill compared to filling to 1,800psi. Man I love the quieter report. Going to have to tackle my 13.4" barrelled QB78D SSG again sometime and see if I can't bring the efficiency up there as well.
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Hey Bob, ................ Sorry for "The Pile" :P
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Bob you ARE the man... as for every thing else I will keep my mouth shut.... its better that way......
Also without going back and re reading all 43 pages..(did it once dont wanna again..) who's idea was the through hammer concept for a fully internal setup??? I would also like to give them credit as that's more or less the version I have scaled for the disco setups that's in the works.....
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Michael, the major variants are in Post # 355 on Page 18.... along with a comparison of their characteristics/losses....
Bob
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Michael, the major variants are in Post # 355 on Page 18.... along with a comparison of their characteristics/losses....
Bob
yes sir! I have all 6 dloaded on my drive for fast reference!! I was curious who's idea was the through hammer version of the SSG itself and didnt notice credit was given at each pic!!! awesome and thanks!!! bstaley it is!!
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New F.A.M.E mod by 22synrodn/triggertreat:
...
Here is more details and the parts needed to do the mod:
(http://i284.photobucket.com/albums/ll14/dkwachob/Forum%20Photos%20Do%20not%20delete/FAME%20Mod%206-10-16%2002_zpsrpc3knbw.jpg)
I am kinda thinking this should be in it's own thread, but here is where it was mentioned ...
Anyway, I my guess is that this will not work right off the bat for a (F.A.D.E.?) discovery. Well, at least not my gun. My gun is a 2400kt that has had a lot of discovery parts installed. The hammer is what came with the gun, which I would assume is of the standard 22xx variety. The lug for the hammer does not thread into it as far as I remember. It simply drops in and is held in place by virtue of the size of the lug below the slot it rides in.
I would need a threaded lug and hammer for this to work, right?
I will be taking my gun apart sometime in the coming week or so (as soon as parts are all here!) and can check for sure...
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I don't think you will be able to tap the hole in the hammer, the Disco hammers appear to be case hardened.... You will likely just break the tap....
Bob
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New F.A.M.E mod by 22synrodn/triggertreat:
...
Here is more details and the parts needed to do the mod:
(https://image.ibb.co/gW3bpa/FAME_Mod_6_10_16_02_zpsrpc3knbw.jpg)
I am kinda thinking this should be in it's own thread, but here is where it was mentioned ...
Anyway, I my guess is that this will not work right off the bat for a (F.A.D.E.?) discovery. Well, at least not my gun. My gun is a 2400kt that has had a lot of discovery parts installed. The hammer is what came with the gun, which I would assume is of the standard 22xx variety. The lug for the hammer does not thread into it as far as I remember. It simply drops in and is held in place by virtue of the size of the lug below the slot it rides in.
I would need a threaded lug and hammer for this to work, right?
I will be taking my gun apart sometime in the coming week or so (as soon as parts are all here!) and can check for sure...
Here is the link to the F.A.M.E. Mod thread: http://www.gatewaytoairguns.org/GTA/index.php?topic=110568.msg1055893#msg1055893 (http://www.gatewaytoairguns.org/GTA/index.php?topic=110568.msg1055893#msg1055893)
Here is the link to the DIY SSG thread: http://www.gatewaytoairguns.org/GTA/index.php?topic=110660.msg1058568#msg1058568 (http://www.gatewaytoairguns.org/GTA/index.php?topic=110660.msg1058568#msg1058568)
Both of these mods together are an awesome combo in my .22 cal synrod and I believe they will make other platforms awesome as well. In my current tune I'm getting 60 shots @ 3.99% with 29.62 FPE average on a 2950 fill. 40 shots at 2.01% with 30.01 FPE average on a 2750 fill. No regulator or valve mod done.
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Okay, I posted my reply in the F.A.M.E. thread... As for the DIY ssg, I have been using the gen1 mod since I found out about it and it made a huge difference for me. I will look at your diy gen2 version though. So far, I have been happy with my gen1 though. I am using a grip frame and it doesn't get in the way for this gun.
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Drawing up a QB SSG before making chips in the shop. I know the plunger is too long. I need to measure the striker throw on my QB but it getting late :-\
There is a ton of room on the back of a QB main tube if you set it up cock on open.
The pics show a cocked stock set above my proposed SSG setup made from a 7/16-20 cap head screw drilled out for the head of a long 8-32 cap head screw and a few custom turned bits.
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Just saw this video in the link below
https://m.youtube.com/watch?v=BSjgKT7hPH8
Is it really possible to hit that efficiency number?. It's 2.36 FPE/CI man
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I don't get that, I get just under 1.9 FPE/CI (which is still excellent).... I used 2600 - 1975 = 625 psi / 14.5 = 43 bar x 13 CI = 560 std. CI.... I took an average of 922 fps (a guess), which is 48 FPE x 22 shots = 1056 FPE total.... 1056 / 560 = 1.88 FPE/CI.... It doesn't state in the Video if the reservoir is stock or if there is an extender.... if so then the volume is larger (and the efficiency less) of course....
Bob
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+Ahsan khan Yes, I do have an extended tank,
It appears he does.
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Ahhhhhhhh.... didn't read the comments.... So the efficiency is lower in proportion to the stock volume divided by what his reservoir volume is....
Bob
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Sometimes the comments are the best part haha.
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Thanks for the rectification! it was a typo while entering the data in online calculator. And thanks for drawing my attention towards tube extension.
It was dumb hasty question indeed.
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Standardized weaponry is not always the best solution. Different applications sometimes require different types of weapons. And this brings me to my point.... AIRGUNS.... One in particular in which I had the opportunity to test (after I purchased it) at first, seemed to be very innovated. But in truth, The "MAC" was and is a disaster. It is privately designed and manufactured by two guys whose name is David & Paul with a startup company named "Inovairtech" I purchased their MACR model (which allows you to load 4 MAC cartridges in a magazine) and one in the chamber for a total of five rounds. The MAC cartridges are about the same size of a .50 BMG shell that you can compress with air to 4500 psi and then push a pellet into the top part of the MAC cartridge. The MACR receiver resembles a M-16 and as the whole rifle looks like a .50 sniper rifle with a fake muzzle brake. The first problem I encounter was that they had manufactured the magazine too small and would not properly fit the designated four rounds and would jam the receiver. The second problem was that after you were successful in loading a round, 75% of the time it jammed the trigger for some reason (there is no built-in safety switch) and would have to eject the round and chamber the next round to make it fire. This would be bad if the shot was critical. (you had no way of knowing you had a jammed trigger until it was too late). But if you worked on the rifle yourself, it would void your warranty with inovairtech. The MAC cartridges are notoriously air leakers! I had one MAC cartridge already loaded in the magazine (along with three others) when it exploded and sent the pellet flying and hitting my shoe ( I had steel toes on). Their whole MAC concept is dangerous and I HIGHLY DO NOT RECOMMEND THIER PRODUCTS TO ANYBODY! I spent serious money on many returns for repair/readjustments postal fees and accomplished nothing. The owners even promised several updated replacement items for my troubles that they never made good on. My advice.... STAY FAR, FAR AWAY! This is a seriously dangerous product item and there are many other good to excellent models out there. Inovairtech is just not one of them!
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There's one guy on the forum that's been working with his trying to get it working good, he's also a problems but nothing like what you had happen, I'm sure that he'll see this thread and no doubt he'll chime in for sure.
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Please, let's not drag this thread off track, it's about the SSG....
Bob
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Here is my stab at it on the B50. I used a cap screw the same thread as the safety bolt but I turned the shank down to 3.6mm so it could slide from thread to head, it was a 2-1/2" M5x8
I didn't want to damage anything so I was able to make a sleeve from shim stock to protect the threads in the end cap where the safety attaches and slip it in the threaded part of the cap after I installed the screw, so far it hasn't moved but its long enough for me to flair the ends if I have to .
(http://i1054.photobucket.com/albums/s483/Garth58/IMG_0094_zps2uq7owei.jpg)
(http://i1054.photobucket.com/albums/s483/Garth58/IMG_0093_zpszljpes4s.jpg)
(http://i1054.photobucket.com/albums/s483/Garth58/IMG_0092_zpshbecmefe.jpg)
(http://i1054.photobucket.com/albums/s483/Garth58/IMG_0091_zpsptayql2e.jpg)
I used the original BAM spring
(http://i1054.photobucket.com/albums/s483/Garth58/IMG_0097_zpsbjmmnpsx.jpg)
My new hammer
(http://i1054.photobucket.com/albums/s483/Garth58/IMG_0090_zpsbo9txm9d.jpg)
I haven't tested for efficiency yet but I finally got it to shoot, it took a bit of reading here to sift through everybody's stories but I like how I can control the power so easily.
I hope it stays where its set without adding set screws.
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Looks good, make sure the rear SSG cavity is vented.... the B-50/51s can pull a vacuum behind the hammer on firing which REALLY hurts the power and consistency of the hammer strike, even moreso with an SSG where the hammer is coasting the last part.... Venting it makes a huge difference.... (thanks Motorhead!)....
Bob
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Thank Bob ...
What a B50 cap looks like vented ...
(http://i1320.photobucket.com/albums/u532/scott_schneider1/DSCF9756_zpsxzce1kwb.jpg)
Hole is drilled on a slight angle to intersect the floor of spring cavity having placed a small pocket in the roof of the spring cavity. In this way the spring or any shims in place do not obstruct air coming in as hammer falls from the cocked position.
* Position of drilled hole found best ( As viewed from rear of action ) at @ 7 to 8 O'clock being along side trigger housing yet Under the stock getting covered up.
There is wood inletting clearance at that position within the stock and venting is hidden and free of garbage getting into the hole.
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I have a different setup and I'm thinking of drilling holes in the tube just before the end cap starts beside the trigger housing.
I have made a sleeve spring guide bushing to help in the spring pocket where I drilled out for a previous MC spring.
(http://i1054.photobucket.com/albums/s483/Garth58/IMG_0100%20-%20Copy_zpsap2tuizz.jpg)
Has anyone ever made a new end cap? I would but indexing the breech screw holes has me worried.
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A new end cap could be done if one had a Lathe & mill.
Because the 2 rear receiver hold down screws are off center creating a radius surface a drill will walk on, Spot facing 2 flats om new cap would be best. Then with new cap in rear of tube held with the side grup screws, transfer drilling threw the threaded holes in tube & then tapping the threads using the receivers threading as a guide would be necessary.
Enough here ... this is an SSG thread !!!
Take this B50 tech into it's own thread please ;D
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I have a lathe but I don't even have a drill press at the moment, not a lot of material there to try to time the theads for the new holes
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Looks good.
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This my version of an internal SSG for the Disco, copy of the one I made for the Marauder, ( TSSG ).
Adjustable for spring preload and separate adjustment for the gap with the modified rear adjuster. Works as a SSG should, I also used fine threads so adjustments are not so touchy.
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Intrigued by the SSG and really like the zero force on valve at rest.
Made a long throw hammer with a variation of the marauder setup for a B51 in 177cal.
Will shoot it more and gather some performance info. Currently doing around 720 with 7.3gr JSBs.
Very consistent and accurate so far.
Thanks Bob for your innovating and sharing.
Cheers
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Which kind of system ( SSG, FFH, TSS ) can improve my QB78D/.177/1500-1000PSI/5-shot PCP ?
In first step I had bean thinking to add adjusting M4 screw only but after read-through this thread I am thinking to add also SSG or FFH or TSS system in one step .
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FFH is a commercial name for the SSG idea pioneered here on the GTA.... There are at least a half-dozen ways to make an SSG.... but not all of them are suitable for a QB.... The photo you show of two springs on a guide is not my understanding of a TSS, I believe they are two, concentric, counterwound springs, operating in parallel, not series as in your photo.... and without the stop on the spring guide.... but that idea may indeed work fine.... Anything you can do to prevent hammer bounce may increase your shot count.... from 5 to maybe 6, or even 7, it depends on how efficient the gun is now....
Bob
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Indeed the device shown in the photo at the bottom is my SSG, internally adjustable only, from my QB78D. I've opted to keep cock-on-close and so access to adjustment is strictly via disassembly, reassembly and testing. Works very well though. Just took more than 15 trial and error adjustments with various springs and lengths and rod lengths before nailing the power/efficiency. That picture isn't the final version - I got some new springs and use a single spring now instead of stacking two. This is the 'final' version (on the same vinyl stool):
(http://www.luthier.ca/other/forum/QB78/QB78D_SSG_20fpe.JPG)
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Bob and Gerard,
Your answers are absolutely short and absolutely understand In another word excellent.
If I understand right If I add only adjusting screw - my picture n.1 - I have to take of "cockin pin" to reach outside adjustment ?
Or what about to add bevel hole on QB78D rear cap and use long screwdriver from outside . Or add the long pin at rear of the guide which will be going trough bevel hole in rear cap.
Disassembling gun for each adjustment is not acceptable for me at all.
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Not sure I could adjust mine from outside. In fact no, it would be too difficult to access. My spring guide is secured by a pair of 10-32 nuts tightened against each other. I need two wrenches to loosen then adjust and re-lock them. The second nut is important to prevent gradually loosening and changing the depth of the probe. You would need to change your QB78 to cock-on-open, more like a Crosman 22xx for example, then drill the end cap and install your SSG to one side of the fixing bolt. I don't find that very practical, if that's even how it is done. A trapped, or internal SSG is fine for me. Just takes more time to get it set up correctly.
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What disadvantage do you see by changing it to the cock-on-close ?
sorry
What disadvantage do you see by changing it to the cock-on-open ?
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Perhaps you mis-worded this question? I left it as stock, the factory method, which is cock-on-close. The drawing you attached shows a simple way (incomplete, perhaps?) of converting to cock-on-open. I suppose the most obvious reason is that without a safety (I remove safeties from my airguns as they are not entirely reliable, and I prefer to use my brain as a safety as it is more reliable than these flimsy mechanisms) it is easier/safer to de-cock the gun by simply opening the bolt. The spring pushes the bolt back, and the hammer spring is no longer in tension, so the gun is safe. A simple, effective action.
With the 22xx style of cock-on-open, the gun is ALWAYS ready to fire until I pull the trigger. The only way to de-cock one of these guns is to pull back the bolt, pull the trigger while holding the bolt back, then slowly release the bolt until the hammer spring is not in compression. This is far too easily fumbled. In fact, I had a 'negligent discharge' of my Brocock Atomic which is also cock-on-open for just this reason, firing a pellet into the kitchen floor tile between my feet and my wife's feet. She had called me from my workshop because a squirrel was on the porch, in the herb planters, making a mess. I grabbed the Atomic carbine (a conversion, scoped) and went to the kitchen window to see if there was a safe shot but the squirrel had gone. I went back towards the workshop, but as I held back the bolt to then press the trigger and slowly release it to de-cock... the bolt slipped from between finger and thumb and the gun fired, splattering both our bare feet with dozens of pieces of lead. It was fortunate that I ALWAYS point the gun in a safe direction, so it was pointed at plain tile, but those little bits of lead hurt. She was very startled. So was I. Seems my fingers had a bit of linseed oil on them, as I'd been polishing an ebony doublebass fingerboard, and that was enough to let me slip. I do not like this method of cocking mostly for that reason. It's unsafe, forcing the user to risk an accidental discharge of a pellet when making the gun safe if a shot has not been taken.
Another reason is that is slightly quicker to cock this way, compared to drawing a bolt back to compress it then pushing it forward and down to lock it. Sometimes a half-second is all the extra time a squirrel needs to get out of my sights. A small difference, but I've found it to be a small advantage with the QB78D's normal cock-on-close system.
I also find it a little bit quieter, as the sear does not *click* past the hammer when cocking, it is already in place ready to hold the hammer back. Small noises can likewise be enough to move a rodent out of the garden, so I have to waste more time waiting for it to return in a few minutes to do more damage to my garden or nut tree.
As for preferring cock-on-close in terms of using an SSG internally instead of protruding from the back, that would only be relevant if my setup showed the rear cap. It does not, as I use a delrin rear plug which serves as a mount for a tubular stock, so I have lots of room inside that tube for whatever shape and size of SSG type setup. If I used a traditional wooden stock I would probably not like that big thing hanging out the back, looking ugly and perhaps catching on my hand.
So not hugely important reasons except for the safety issue mentioned first, and that one alone is enough that I wish the rest of my airguns were cock-on-close type.
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Thanks for your investigating.
I accept lower safety and noise differnces but most important not acceptable what I see now is differnce from obviosly use gun systems .
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Wow! glad no one was hurt from such a dangerous method.
Pointing the gun between you and your wife's feet is NOT as safe direction to uncock a gun. Shocked that you thought it was.
Never, ever uncock a bun by pinching the bolt between thumb and fingers. Why? I think you just learned WHY!
Wrap your index finger firmly around the bolt. No way for it to slip through when you are using this method. . Your method is extremely dangerous, as you have now learned. Even a tiny bit of lube or sweat, and the pinch method is a bombshell. Almost guaranteeing an accident. Had this been a HP PB, it could have been disastrous for the both of you. :(
Now, all that is needed to cock a "to the rear" cocking system silently, is to pull the trigger on a non cocked gun, pull bolt fully to the rear, and release trigger then close the bolt. The gun is now cocked, without the click. ;)
As you say, the brain is the best safety, but you do have to engage brain in order for it to be safer than the mechanical safety. LOL ;D
Knife
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The gun was pointed straight down at 1/2" thick ceramic tile over 1/2" of concrete, and was shooting with about 6fpe of energy. I was walking back to my workshop and was not expecting to let go of the bolt until getting to my shop door. Have you looked at a Brocock Atomic bolt knob? It's a tiny, shallow , round glossy thing sticking straight out the back of the upper. How exactly would you suggest grasping such a poorly thought out device if nit between thumb and finger? A pair of pliers, perhaps? But no, that would probably make it even easier to slip. I have since made a brass T handle because that incident demonstrated the inherent problem with Brocock's design. I have zero trouble de-cocking since.
Not trying to make excuses, and sure, it was a bit cavalier de-cocking as I walked, but I was very conscious of muzzle direction and the worst potential damage happened: minor momentary stinging from a sub-500fps pellet fragmenting as it splashed horizontally. I understand there's a tendency for knee-jerk harsh critiques whenever someone 'confesses' to an ND (hey, I've hung out on /k/ a little and seen how quickly those conversations descend into the absurd), but it was a heck of a lot safer than pointing the thing at a wall and there was zero potential for actual injury, not enough energy left after hitting that hard surface to draw blood from lower extremities. If you happen to be in the mood to attack someone so be it, doesn't hurt me, I'll just ignore any further attacks from you and move on.
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It is easy to judge in hindsight. A lot that going on these days unfortunately. I'm fairly sure you will be more conscious going forward as I am after my own mishap awhile back. I think you were being careful by your words, but it still bit you. You are probably one of the safest shooters around now after your experience. Thanks for sharing so others may benefit.
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Yup, that's about how it is. I'm extra-cautious whenever handling any airgun, triple checking anything which could bite. My son had a similar moment last year on his first day of shooting at a range, when he got careless and fired a pellet at the roof of the shed we were in with a few other shooters. It was only a 3fpe .177" pellet and didn't even dent the roof steel, but the noise scared the heck out of him and he will always remember to keep his finger off the trigger when not intending to shoot after that scare. He's been solid about it ever since.
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Don't know what "/k/" is, and wasn't attacking you. I think you figured out for yourself, that it was not safe. That is what going outside to decock such a dangerous combo is for.
And as stated, glad you were not hurt, and sorry you feel that way. I hope your feelings of being attacked are not simply macho bravado. What you did is dangerous. We should NEVER use the excuse that an AG is less powerful that a powder burner to ignore safe handling practices. ;)
Knife
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So now it's "macho bravado." Previously there was this:
Pointing the gun between you and your wife's feet is NOT as safe direction to uncock a gun. Shocked that you thought it was.
Nothing insulting there at all, obviously...
And then there's this:
"As you say, the brain is the best safety, but you do have to engage brain in order for it to be safer than the mechanical safety. LOL ;D"
Perhaps just a flippant, offhand remark, but in the context of your overall tone it seems more likely a direct impugnment of my mental faculties. Smiley doesn't help, really, nor does the "LOL" - slapping someone then saying 'just kidding' doesn't really fly in the real world.
"Had this been a HP PB, it could have been disastrous for the both of you. :( "
Implying what, that I'd de-cock a high powered firearm in the kitchen of my UPSTAIRS APARTMENT??? That I'd even use a high powered firearm in the yard? I don't know what sort of wild West fantasy you live in, but that has nothing to do with my reality. There exist no 'high powered firearms' in my house and none will come, my interests don't run in that direction. Then you go on to suggest an equally unsafe practice for silently cocking a gun. Do you not see the irony, having just scolded me about my bad practices?
"Now, all that is needed to cock a "to the rear" cocking system silently, is to pull the trigger on a non cocked gun, pull bolt fully to the rear, and release trigger then close the bolt. The gun is now cocked, without the click. ;)"
Perhaps the winking smiley face makes it less potentially dangerous? But no thanks, I'll not be doing sneaky things with the trigger pulled while cocking just to keep it quieter... yikes, talk about unsafe gun handling. Remember when you said this?
"Never, ever uncock a bun by pinching the bolt between thumb and fingers. Why? I think you just learned WHY!"
Do you not see that this is EXACTLY the same level of danger as pulling the trigger while cocking the gun? What happens if the bolt slips from your fingers with your finger still on the trigger? Or have you somehow magically become error-proof because of your intentions to cock the gun silently rather than to de-cock using a virtually identical method? Your hypocrisy undermines what may well be your good intentions. Your insulting tone, persisting through a half-dozen comments aimed at me, does your argument for safety no good whatsoever. Perhaps a good idea might be to type out your more emotion-laden posts, then walk away for a few minutes, then come back and read them before posting, editing out any blatant contradictions and insults you don't really intend.
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Gentlemen Pleas take this off line via the PM. I would prefer to leave this thread running but if these exchanges continue I will be forced to lock the thread. This applies to all concerned !!!
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Indeed the device shown in the photo at the bottom is my SSG, internally adjustable only, from my QB78D. I've opted to keep cock-on-close and so access to adjustment is strictly via disassembly, reassembly and testing. Works very well though. Just took more than 15 trial and error adjustments with various springs and lengths and rod lengths before nailing the power/efficiency. That picture isn't the final version - I got some new springs and use a single spring now instead of stacking two. This is the 'final' version (on the same vinyl stool):
(http://www.luthier.ca/other/forum/QB78/QB78D_SSG_20fpe.JPG)
Have you ever looked at my DIY SSG build Back to DIY SSG Build (http://www.gatewaytoairguns.org/GTA/index.php?topic=110660.msg1108165#msg1108165). It is for the Marauders but you might be able to incorporate the internal spring adjustment section to your build so you don't have to take the gun apart to adjust the spring tension.
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I certainly have followed that thread triggertreat, but fail to see how it could apply in a cock-on-close QB78D. The bolt which secures the rear plug to the upper is bang on centre, making access to anything in the centre impossible. In the case of my build this long bolt also secures the rear of the grip frame, a 22xx type which is snuffed against the cylinder with a shaped brass shoe, through which this bolt first passes. Removing that bolt for access to the SSG would necessitate some sort of added device to secure everything else... perhaps something like a large, elaborate barrel band. Not really viable, though obviously it'd be nice to have external adjustment access.
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I certainly have followed that thread triggertreat, but fail to see how it could apply in a cock-on-close QB78D. The bolt which secures the rear plug to the upper is bang on centre, making access to anything in the centre impossible. In the case of my build this long bolt also secures the rear of the grip frame, a 22xx type which is snuffed against the cylinder with a shaped brass shoe, through which this bolt first passes. Removing that bolt for access to the SSG would necessitate some sort of added device to secure everything else... perhaps something like a large, elaborate barrel band. Not really viable, though obviously it'd be nice to have external adjustment access.
Oh well, I was simply looking at the photo and have no knowledge of the QBs inner workings. It looked like a possibility from that one photo. If the bolt has multiple functions then I guess not even in the cock on open setup.
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The simplest way I could see to make an SSG/TSS work with a QB78 would be to tap larger threads into the rear plug, then use separate bolts from above and below to secure the receiver and grip frame to the main tube respectively. Keeping those bolts short enough that they secure a few turns of thread but don't interfere with a threaded hole fore/aft would allow an adjustable hammer spring device of whatever sort, even an RVA. But the dimensions are quite small, so something of quite a bit larger diameter and maybe fine threads would probably be a good idea to avoid stripping them out with such short engagement, especially if something like a 1/2"-20tpi adjuster was wanted. With cock-on-open mods it becomes possible to use a sort of off-centre RVA at least, something which rsterne has explained elsewhere as have others. But that doesn't help with an SSG or TSS.
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My version for a QB is way back on page 10.... http://www.gatewaytoairguns.org/GTA/index.php?topic=102095.60 (http://www.gatewaytoairguns.org/GTA/index.php?topic=102095.60) .... in Reply #66....
Bob
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Thanks for the reminder of where that great write-up was Bob. I read that back when I started fiddling with my QB78D, but decided to go with all-internal, sacrificing the convenience of external adjustability for something which preserved the cock-on-close function and was just generally simpler. Install, tune, forget about it. I'd already tuned my QB for just shy of 20fpe with 18.13gr, per HFT limits and a suitable power level for squirrels, so installing an SSG was mostly a matter of getting that back with a different spring setup and reaping the improved efficiency of the SSG. Mine's giving me over 125 shots at 19.8fpe with an efficiency of 1.37fpe/ci, pretty much identical to your regulated QB SSG result. In my case it's with a slightly heavier pellet, 5.8fpe less power per shot, about 27% higher shot count, and through a 13.4" barrel which was a bit problematic in the initial tuning phase - trying to find efficiency with such a short barrelled PCP was a challenge. Mine's also regulated to around 1,200psi output. But a lighter hammer and now the SSG got that all sorted out. Lovin' it!
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Found this thread on a Russian airgun forum (posted April of 2015).
Is this what I think it is? A prod SSG type device?
Brass doesn't look threaded to me...no way of adjusting. Which leads me to believe just a spring guide.
(http://i1172.photobucket.com/albums/r563/mkdive/Airguns/11677506_zpskez7wsb8.jpg) (http://s1172.photobucket.com/user/mkdive/media/Airguns/11677506_zpskez7wsb8.jpg.html)
(http://i1172.photobucket.com/albums/r563/mkdive/Airguns/11677502_zpshqznampn.jpg) (http://s1172.photobucket.com/user/mkdive/media/Airguns/11677502_zpshqznampn.jpg.html)
(http://i1172.photobucket.com/albums/r563/mkdive/Airguns/11677508_zpsy881z2xk.jpg) (http://s1172.photobucket.com/user/mkdive/media/Airguns/11677508_zpsy881z2xk.jpg.html)
(http://i1172.photobucket.com/albums/r563/mkdive/Airguns/11677530_zpsknox5iuo.jpg) (http://s1172.photobucket.com/user/mkdive/media/Airguns/11677530_zpsknox5iuo.jpg.html)
(http://i1172.photobucket.com/albums/r563/mkdive/Airguns/11677528_zpsozamugpf.jpg) (http://s1172.photobucket.com/user/mkdive/media/Airguns/11677528_zpsozamugpf.jpg.html)
Link to the page of the thread: http://forum.guns.ru/forummessage/96/803826-52.html (http://forum.guns.ru/forummessage/96/803826-52.html)
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Found this thread on a Russian airgun forum (posted April of 2015).
Is this what I think it is? A prod SSG type device?
Brass doesn't look threaded to me...no way of adjusting. Which leads me to believe just a spring guide.
(http://i1172.photobucket.com/albums/r563/mkdive/Airguns/11677506_zpskez7wsb8.jpg) (http://s1172.photobucket.com/user/mkdive/media/Airguns/11677506_zpskez7wsb8.jpg.html)
(http://i1172.photobucket.com/albums/r563/mkdive/Airguns/11677502_zpshqznampn.jpg) (http://s1172.photobucket.com/user/mkdive/media/Airguns/11677502_zpshqznampn.jpg.html)
(http://i1172.photobucket.com/albums/r563/mkdive/Airguns/11677508_zpsy881z2xk.jpg) (http://s1172.photobucket.com/user/mkdive/media/Airguns/11677508_zpsy881z2xk.jpg.html)
(http://i1172.photobucket.com/albums/r563/mkdive/Airguns/11677530_zpsknox5iuo.jpg) (http://s1172.photobucket.com/user/mkdive/media/Airguns/11677530_zpsknox5iuo.jpg.html)
(http://i1172.photobucket.com/albums/r563/mkdive/Airguns/11677528_zpsozamugpf.jpg) (http://s1172.photobucket.com/user/mkdive/media/Airguns/11677528_zpsozamugpf.jpg.html)
Link to the page of the thread: http://forum.guns.ru/forummessage/96/803826-52.html (http://forum.guns.ru/forummessage/96/803826-52.html)
Those Ruskies got it going on. there are some cool guns in that thread.
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That looks a lot like the one I made for the Disco and The Mrod except my version installs the other way around.
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This is an interesting thread. Bookmarking for future reference. It also answers some questions about development history of this SSG. I guess I'll start referring to it more correctly now
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WOW! Sounds like a great idea however, I think the nomenclature should be kept simple. I'm thinking something like "SSG2" or if you want to be more highbrow maybe "SSGII"
HAVE FUN,
BE SAFE,
CHEERS,
Kenny
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I don't see any threads on that Russian spring guide.... so therefore no way to "Stop" the guide, it simply travels with the hammer.... ie an SG, not an SSG.... It does make a cocking indicator, however.... and with the addition of a sliding O-ring (and a bit more length), gives you a way to directly measure the actual valve lift....
(http://i378.photobucket.com/albums/oo221/rsterne/Discovery/IMG_3493_zpsf3b2824b.jpg) (http://s378.photobucket.com/user/rsterne/media/Discovery/IMG_3493_zpsf3b2824b.jpg.html)
Slide the O-ring up against the preload adjusting bolt, then cock and fire the gun.... the O-ring gap to the adjusting bolt after firing = valve lift....
(http://i378.photobucket.com/albums/oo221/rsterne/Discovery/IMG_3491_zps82051661.jpg) (http://s378.photobucket.com/user/rsterne/media/Discovery/IMG_3491_zps82051661.jpg.html)
Bob
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Just want to say thanks to everyone for sharing all your info on the development of the various SSG devices. I made an extended one for my 2400 to hold a longer spring and am now launching 14gr CPHP
at 885 fps. I noticed I get more shots after I close the bottle than before. I'll see how many shots I can get before it falls off tomorrow.
One thing that really surprised me was that I shot 3 in a row all at 886.6 fps and the fourth at 886.7. It was right before it fell off the regulator, the spread was a little higher after I topped it off.
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just commenting to make it easier for me to find this thread to in the future....
i mentioned building a 2260 in .25 with a flying hammer in another tthread the other day with no prior knowledge of this thread.....today i see and see Bob has already worked out all the kinks for me to hit the goals.i have in mind, both in mechanics and performance (and probably appearance too!)
Thanks Bob!
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Ok Guys
It has been several months since Bob, (Dr. AR) presented his SSG build, 8)
for us rabid air gunners to drool over, build and use in just about every AR.
Any NEW info you would care to disclose on your SSG build?
After 45 pg's+ of discussions, thoughts and Ideas etc, IMHO, one of the BEST posts on our site,
for main stream users, and not model specific with a few exceptions etc.
I hope/believe that there would be more follow up,
on anything you would change, to make it better, TEST results, especially using Co2 etc.
I just gathered/received all the parts for my SSG build, for the dual fueled QB 79, 22 cal,
I am building the 4th one from the top in this post,
https://www.gatewaytoairguns.org/GTA/index.php?topic=102095.340 (https://www.gatewaytoairguns.org/GTA/index.php?topic=102095.340)
Come on Guys, spill the 411 on the new results. ;)
Tia,
Don
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me too Im about to start gathering parts for the DIY Marauder SSG. Then when its done I will go for the Huma Regulator and that's it. I just want average middle of the road power and consistency and not extreme power.How much are all those "spring parts" all together cost?
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me too Im about to start gathering parts for the DIY Marauder SSG. Then when its done I will go for the Huma Regulator and that's it. I just want average middle of the road power and consistency and not extreme power.How much are all those "spring parts" all together cost?
FYI, From now, until Dec 31st, we have our HDD, that normally goes for $49, only $39 if they mention the GTA. It gives a Marauder 50% more shots, and LOTs Quieter. All who come to our shop and see one with vs. without HDD are amazed at how much quieter it is.
I'd bet dollars to donuts you'll be just as pleased .
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me too Im about to start gathering parts for the DIY Marauder SSG. Then when its done I will go for the Huma Regulator and that's it. I just want average middle of the road power and consistency and not extreme power.How much are all those "spring parts" all together cost?
Which SSG version are you refering to? Bob and motorhead made an external DIY version while oldpro and myself made an internal version. Mine is a DIY version while oldpro replaced his SSG with a TSS commercially available version.
I tell ya, the SSGs do work good, but for a regulated gun setup a light weight hammer and valve spring typically will give you better efficiency vs a stock hammer weighted SSG in my experience. Both type setups are better than the stock setup though for increased efficiency/shot count.
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me too Im about to start gathering parts for the DIY Marauder SSG. Then when its done I will go for the Huma Regulator and that's it. I just want average middle of the road power and consistency and not extreme power.How much are all those "spring parts" all together cost?
Which SSG version are you refering to? Bob and motorhead made an external DIY version while oldpro and myself made an internal version. Mine is a DIY version while oldpro replaced his SSG with a TSS commercially available version.
I tell ya, the SSGs do work good, but for a regulated gun setup a light weight hammer and valve spring typically will give you better efficiency vs a stock hammer weighted SSG in my experience. Both type setups are better than the stock setup though for increased efficiency/shot count.
Agree .... within modest power & regulated with a LIGHT hammer works great !! Combined with an SSG they can be phenomenal in low cyclic vibration & air use.
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Keith, right now I'm studying your build guide updated September 28 2016. It has like 22 parts/tools to gather. It may take a little while to have all parts in. I will have to find Motorheads build thread to study the build.
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Well I am glad you found my DIY SSG on this thread. I couldn't find the full spiel I did on it on this thread, but did find it on the thread I created for it here:
https://www.gatewaytoairguns.org/GTA/index.php?topic=110660.msg1056871#msg1056871 (https://www.gatewaytoairguns.org/GTA/index.php?topic=110660.msg1056871#msg1056871)
The hardest part for me was drilling out the gap adjuster for the screwdriver to pass through. The rest was easy.
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I am considering buying a Hatsan Gladius/Bull boss and having made several SSGs for different guns and being impressed with the results I will obviously be looking to do the same to the Hatsan, however apart from an exploded diagram which doesn't really tell me just where and how much space is available, I was hoping somebody here has done this mod to the Gladius/Bull boss? or at least share some parts pics once disassembled?
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I am considering buying a Hatsan Gladius/Bull boss and having made several SSGs for different guns and being impressed with the results I will obviously be looking to do the same to the Hatsan, however apart from an exploded diagram which doesn't really tell me just where and how much space is available, I was hoping somebody here has done this mod to the Gladius/Bull boss? or at least share some parts pics once disassembled?
There is very little space to work with in there. You essentially have to make everything work within the diameter of the factory hammer spring, which ain't much :( I made one for my Bullboss sometime back, and it did work. The cocking force required for higher power was a bit much for me. I took it out, because I like my gun easily adjustable, and I'm prone to swapping cylinders for completely different power levels/regged/unregged. The way it is designed, it will be hard to make one that is easily adjustable without removing the stock. I didn't take any pictures of mine when I did it. If you have a lathe and good machining skills, I'm sure you can come up with something. I deemed it not worth the trouble in my particular case, but that may not be true for you. If you plan on setting the gun on a certain power level and leaving it, then it may be more viable for you :)
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Trying to make an SSG for an Artemis P15
using softer spring i cant get the 27 fpe even prealod the spring till not cocked
using original spring i get the power but if i let a small gap (2mm) from the hammer to ssg the power drops 10 fpe
the hammer weight is 20 grams, the valve travell is 1.2 mm, the hammer travell is 4.44 mm
Any advice ?
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Trying to make an SSG for an Artemis P15
using softer spring i cant get the 27 fpe even prealod the spring till not cocked
using original spring i get the power but if i let a small gap (2mm) from the hammer to ssg the power drops 10 fpe
the hammer weight is 20 grams, the valve travell is 1.2 mm, the hammer travell is 4.44 mm
Any advice ?
Stiffer spring
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Is there a way to increase the striker stroke on this gun? .050" or .100" more stroke would give you a harder hit on the valve.
Steve
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Flatten some soft lead pellets inside the hammer to bump up the weight slightly or increase the spring rate.
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Hi all,
Thanks to this thread, I worked on an internal SSG idea, and gave it to my friend. He designs and custom builds his own line of HFT rifles. Yes, all rifles are initially setup for sub 12fpe, but thanks to the SSG, the velocity is fully adjustable. My rifle, his first ever prototype will run 788fps with 8.44gr for HFT competition, but the velocity goes up to 948fps if I set the SSG to full pre-load.
As seen in the last foto, velocity can be adjusted without stripping the rifle.
Thanks for all the great input to this thread.
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Hi wimpie, firstly I want to say nice execution on the SSG.
Secondly, I want to make a suggestion. Assuming these HFT rifles are regulated, there’s a good chance the setup is not optimized for the 12fpe level. It is enticing to have the ability to adjust up to 16.8fpe with only a hammer preload adjustment, but by backing down to 12fpe, the valve’s lift and dwell will be more susceptible to slight variations in hammer strike, thus driving up the extreme spread. Given the highly competitive nature of Field Target, I suspect your friend is looking for every imaginable advantage. In which case it may be worth reducing the regulator’s setpoint until you hit a bit over 12fpe (say, 820fps with 8.4gr) with maximum preload, then reduce the preload until it’s at 12fpe. When set up in this manner, the extreme spread should be very small, as well as being more tolerant of slight variations in the regulated pressure.
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I've tried both internal and external versions of the SSG on my Marauder. Both work well, but I prefer the internal version since nothing sticks out when cocked. I wish I had made the custom end cap 1/4" deeper because I didn't have room for the stock spring preload adjuster. I must insert washers to adjust the power.
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Pretty much the same design here as well. Added a lock washer that was heated and compressed in a vice that keeps the spring from spinning and helps lock it in to the nylon pre-threaded nut. Used this exact same design in both Gen 1 and Gen 2 Marauders with very good results. One note, file the top surface of the bolt as it generally has raised lettering from the manufacturer.
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SSG for kral puncher breaker
https://www.youtube.com/watch?v=Hb303lT6IB0 (https://www.youtube.com/watch?v=Hb303lT6IB0)
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What stops the entire bolt, spring and nut from spinnning when you turn it with the inserted flat head screwdriver ?
I know the goal is to have the bolt turn but not the nut so that the nut will tighten or loosen against the spring to adjust tension.
Pretty much the same design here as well. Added a lock washer that was heated and compressed in a vice that keeps the spring from spinning and helps lock it in to the nylon pre-threaded nut. Used this exact same design in both Gen 1 and Gen 2 Marauders with very good results. One note, file the top surface of the bolt as it generally has raised lettering from the manufacturer.
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hey all,
I've got a "project gun" I'm working on, a 2400KT that I added a Disco air tube and inards to, and I bought a regualted HPA tank that's going on next. I thought while I was at it I would install an HDD. I ask a friend (an airsmith) where he bought his and said he'd never bought one, he made his own take on an SSG. Which got me here. Anyway I read a few pages and decided that I wanted something internal to gun and managed to re-invent the "through the hammer guide" (I thought I was so smart, and here it had already been done).
I also am playing with a new (to me) CAD program so I thought I'd share the drawings.
(http://Stock Disco Hammer.pdf)
I saw a question on one of the other posts about how do you keep the adjustment nut from spinning, something I wondered about until I did the drawings. If you look at the Kinetic Hammer drawing (yeah, my name for the SSG I re-invented) you'll see that if you remove the gap adjustment screw at the back of the tube when you cock the hammer it drives the adjustment nut back against the end cap and the guide rod has no tension on it. So, turning the guide rod should be easy and the nut is held in place by the spring tension.
One thing that I found was the stock spring is much too long in the new design. the load adjsutment nut (threaded nylon spacer) takes up .3in and reduces the spring compression space by about .4in. I manageed to get .1in back by relieving the head of the hammer for the head of the guide and I'm thinking of making the guide a little longer but in the mean time I found a spring that is 1.75 in (free length) @ 8.4lbs/in which should give me a pre-load of 4.9 lbs and a cocked load of 9.66 lbs, stock is 4.26lbs and 9.48lbs, based on a stock spring of 2.07in (free length, I measured it) @ 8.7 lbs/in (I'm told this is the "old" disco spring, the new one's are stiffer)
I'm going to be gone for a while and won't get back to this until mid June. I'll let you know how it works out.
Okay, how do you insert an image into the message? can you insert a pdf or does it have to be an image file (jpg?)
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Here's a screenshot of your drawing.
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Cool! Gerard, how did you save the screen shot as a jpg?
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Okay, I found a screenshot tool that works with my version of windows lets see it I can insert a png
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Any image editing software should let you save in multiple formats. I'm using Windows 10 Pro, and have liked XnView for most image editing for over a decade. CtrlShiftV drops a screenshot (PrtScrn key) into XnView then I just crop and save.
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John, that looks like a very successful adaptation of the version of the SSG suggested by bstaley in Reply #355, third drawing down....
https://www.gatewaytoairguns.org/GTA/index.php?topic=102095.340 (https://www.gatewaytoairguns.org/GTA/index.php?topic=102095.340)
There is a note explaining the operation of it at the bottom of that Reply in blue....
Hope you get the adjustment range you need for your project.... It looks nicely executed....
Bob
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Thanks Gerard, Bob,
Yes, it is the bstaley design. I was really bummer when I realized I'd re-invented an existing design...
I read the post that explained it after you pointed it out to me.
The current design has an adjustment range of about 1 lb. I think I can increase the range by increasing the length of the guide so that the adjustment collar sits all the way back against the back cap when it is full out (the guide rod will slip into the back cap by about .13
I also thought about inletting the front of the hammer to go past the end of the valve stem (the valve stem is .33 long) but I don't know how much the valve stem moves when it's struck, I wouldn't want the hammer face to hit the valve body.
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If you allow half the valve throat diameter for the valve lift, that is plenty.... Efficient tunes end up at 1/4-1/3 the throat diameter for valve lift.... On a Disco valve, that only means about 1/8" of travel required, but in reality I have never gone that little.... If you check the valve, the spring is probably going coil bound when the stem is still protruding 1/16" or so, so that extra length is totally useless.... With the spring coil bound, there is nowhere for the air to get through it from the valve entrance to the exhaust port....
If you shorten the valve stem, it lengthens the hammer stroke.... Be careful of that, as the cocking pin can impact the front end of the slots in the tube and/or receiver.... or the back end of the bolt.... when fired.... That is hard on the pin, and if it hits the bolt can cause the handle to pop up on firing.... IIRC, you can shorten the stem about 0.070" without problems (or recess the front of the hammer that far)…. Beyond that, you have to work on the slots and the back of the bolt.... Don't shorten the bolt too much, or you can't cock the gun.... ::)
Bob
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Wow, good data!
I went back to the drawing and legthened the guide which gave me another .130 adjustment and then changed the .25 threaded nylon spacer for a .125 threaded steel spacer (another .125) for a total adjustment range of .260 (assuming a solid spring length of .6in)
I ran some numbers and using the stock spring (assuming a rate of 8.7lbs)
In the stock config the load would be 9.46 lbs for a spring that is 2.07in @ 8.7 lbs/in.
It has an adjustment range of 10.57 to 12.78 lbs in the SSG configuration.
I found another spring that is shorter, 1.78 in, and heavier, 10 lbs, which will give a range of 9.25 to 11.8 lbs with a pre-load of 3.9 to 6.15 lbs in the SSG configuration.
I'm thinking I'll try the stock spring first but the other spring I found is only $1.37 so I'll probably order a couple of them too.
I've desided not to relieve the head past the guide face so I won't have to worry about the cocking pin.
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Bob, Scott and the rest of you that inspire.
Just a quick tale of SSG internal pg18 the number 6 design. My BSA r10 mk2 is dialed in just a few days! Had to make a new rear plug for the SSG flat washer to seat. The seat was non-adjustable but then I had a very good idea where it would end up. Only one trip to the lathe to get the depth correct (an increase of depth of one mm).
Following the readable recipe. Regulated shot string with descending FPS and there is too much hammer spring tension OR too much regulation pressure. Shot string with bump up in the later part of the numbers and there is not enough hammer spring tension OR not enough pressure on the reg. Had to chase my tail for about four tins of pellets....
The end result was exceptionally rewarding. The result was 900fps 18gr JSB for 60 shots on 280cc or 40 shots on the 200cc bottle. With a standard deviation of 3.9% Whoo hoo. Not the most efficient at 900fps resulting 1.04FPE but satisfactory for my pesting and hunting tasks at hand.
Stock I could only get out 850fps max hammer spring tension and then a disappointing 30 shots and 20 shots respectively. I could eventually hear excess air consumption after my end results adding the SSG of the sharpened report sound. If a person does not know what he is listening for then you cannot hear it.
The world of air gunning advances. The BSA is nice but still love and passion for my antiquated B-50.
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What stops the entire bolt, spring and nut from spinnning when you turn it with the inserted flat head screwdriver ?
I know the goal is to have the bolt turn but not the nut so that the nut will tighten or loosen against the spring to adjust tension.
Pretty much the same design here as well. Added a lock washer that was heated and compressed in a vice that keeps the spring from spinning and helps lock it in to the nylon pre-threaded nut. Used this exact same design in both Gen 1 and Gen 2 Marauders with very good results. One note, file the top surface of the bolt as it generally has raised lettering from the manufacturer.
I have recently finished an SSG for my Kral Puncher Pro 500 but because of the somewhat different design of the hammer etc i had to redesign a new hammer, mine is a bit more refined as i have spring guides.
(https://i.imgur.com/Gmw7vZm.jpg)
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Come end of the day I think it is safe to say SSG devises or a hammer in Free Flight against a heavy spring simply works FAR better in most applications than a hammer in preload against the poppet stem ... FAR FAR better !
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Another happy user of the SSG concept. I made "cocking indicator" style SSG's for my Marauder and Challenger (so easy in this one) and was rewarded with an astounding increase in efficiency out of both.
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Bob's Quote,
"Considering all of the above.... WHY in heaven's name would you want a progressive spring that requires more force at the end of its stroke to develop a given hammer energy and momentum?.... That seems completely the WRONG way to go.... :o"
Here is some info I can offer up........
The progressive rate springs (round wire) I have used are from the 60-70's and made by Wolf,
these spring were called Vari-rate Springs) and came in numerous #'s rating etc.
They were color coded on the softer end, so you could run them either way,
meaning you could use the hard end first at the start of compression stroke or the other way around.
Once you found a rate of the spring that almost worked but was slightly to hard (stout),
you trimmed a quarter or half a coil off the hard end and tried it again until you got the stack just right.
On my Coonan's, I got them so they could shoot 38 Spcl and 357 Mag loads with the same spring etc.
I have not used/tried the Vari-Rate Spring since.........I only use Flat Wire Springs now.........
On the Flat Wire springs, I have several different rates,
(I am using SSG design #4 from the top, only the stop washer is NOT recessed into the hammer base,
it sit against the end of the hammer and the spring guide rod tip fits inside the spring tunnel of the hammer).
All these type of springs are designed to fit inside the spring tunnels of the slides on the different brands of Semi-auto pistols,
most springs tunnels are .460" +/-, and the outside diameter of the spring rods run .250 to .320"+.
inside diameter of the flat wire springs run .250 to .320" + etc.
If you are using the #4 type of SSG, where the spring rests on the rear of the hammer,
I can't see where they would cause any problems other than spring rate,
the diameter of QB/Gauntlets hammers are just under the .750" diameter and some are even larger, ie Mrod etc.
I can't see using a hammer springs that is so hard to cock, when you can use a Flat Wire spring,
that you can use 1 finger to cock and still provide the operating spec's needed.
YMMV,
Bob
Have you used the new flat wire spring? If not, I would be willing to send you a couple for testing,
all I will need is the pound rating you want.....
the pound rating available are 11 to 24 #'s for the Colt series, and I am not sure of the ratings for the other brands etc.
I hope you DON'T Mind me using, some of your drawings from your back post (2016),
to show the different types of SSG's made by everyone...........as I have seen a lot of the photos/drawing are gone already.
Tia,
Don
Here are all the major variations of the SSG that have been invented so far.... They all share two common traits.... there is preload in the spring, but the spring does not push on the hammer at rest when uncocked.... These two features combine to prevent hammer bounce.... The concept first discussed was to use a Gas Ram to achieve this, but unavailablitly of a suitable unit caused me to simulate the way it worked by using a spring on a guide with a stop to create the preload and a gap to the hammer.... Here are the various configurations suggested to date, some tried and some not.... All these drawings share the same features and were drawn to the same scale, although they may have changed slightly by the time they got uploaded....
1. They have the preloaded spring 10 units long. Spring and guide is shown in black.
2. They have a hammer stroke of 7 units, with enough room for that to occur everywhere.
3. They have an adjuster (shown in red) for the gap between the hammer guide and hammer, which also changes the distance the spring compresses when cocked.
4. The green feature is the end cap, all end caps and gap adjusters are drawn the same size.
5. The hammer is shown in purple, and is longer for the ones that require a deep hole in it.
6. If a sliding collar is required on the guide, it is shown in blue.
(http://i378.photobucket.com/albums/oo221/rsterne/Parts%20for%20Sale/SSG%20Gas%20Ram_zpshzvard5u.jpg) (http://s378.photobucket.com/user/rsterne/media/Parts%20for%20Sale/SSG%20Gas%20Ram_zpshzvard5u.jpg.html)
Gas Ram suggested by stalwart
(http://i378.photobucket.com/albums/oo221/rsterne/Parts%20for%20Sale/SSG%20Original_zpsc7o9n5b6.jpg) (http://s378.photobucket.com/user/rsterne/media/Parts%20for%20Sale/SSG%20Original_zpsc7o9n5b6.jpg.html)
SSG suggested by rsterne
(http://i378.photobucket.com/albums/oo221/rsterne/Parts%20for%20Sale/SSG%20Through%20Hammer_zpsucpfddqr.jpg) (http://s378.photobucket.com/user/rsterne/media/Parts%20for%20Sale/SSG%20Through%20Hammer_zpsucpfddqr.jpg.html)
Above suggested by bstaley.
(http://i378.photobucket.com/albums/oo221/rsterne/Parts%20for%20Sale/SSG%20Fixed%20at%20Rear_zpsn0bgtpm0.jpg) (http://s378.photobucket.com/user/rsterne/media/Parts%20for%20Sale/SSG%20Fixed%20at%20Rear_zpsn0bgtpm0.jpg.html)
Above suggested by Gippeto.
(http://i378.photobucket.com/albums/oo221/rsterne/Parts%20for%20Sale/SSG%20Fixed%20in%20Hammer_zpsimygf31t.jpg) (http://s378.photobucket.com/user/rsterne/media/Parts%20for%20Sale/SSG%20Fixed%20in%20Hammer_zpsimygf31t.jpg.html)
Above suggested by I_like_Irons
(http://i378.photobucket.com/albums/oo221/rsterne/Parts%20for%20Sale/SSG%20Loose%20Guide%20Stationary_zpszp4xodm4.jpg) (http://s378.photobucket.com/user/rsterne/media/Parts%20for%20Sale/SSG%20Loose%20Guide%20Stationary_zpszp4xodm4.jpg.html)
Above suggested by rsterne
(http://i378.photobucket.com/albums/oo221/rsterne/Parts%20for%20Sale/SSG%20Loose%20Guide%20with%20Hammer_zps3tmneipu.jpg) (http://s378.photobucket.com/user/rsterne/media/Parts%20for%20Sale/SSG%20Loose%20Guide%20with%20Hammer_zps3tmneipu.jpg.html)
Above suggested by rsterne
It is not the intention here to show every possible variation of materials or construction, but only the major differences in operating methods.... In my original design, the spring is captive in the rear gap adjusting nut, is accelerated by the spring and comes to a halt just before the hammer hits the valve, wasting the energy used to accelerate it.... After my original design, which several people have tried, two variations were proposed in which the guide was fixed at one end.... In Gippeto's version, it was fixed at the back, adjustably, into the gap adjuster in the end cap.... The guide does not move, the spring does its work pushing against a sliding collar which then pushes on the hammer.... The collar stops just before the hammer hits the valve.... No energy is used in accelerating he guide, only the small collar.... but the weight of the guide does not assist the hammer strike.... In a version proposed by I_like_Irons, the guide is fixed in the hammer and travels with it, but maintains preload adjustability where it threads into the hammer.... It also uses a sliding collar on the guide, but at the back, pushing on the gap adjusting nut.... The weight of the guide takes energy to accelerate, but that energy becomes part of the hammer strike....
The two remaining versions I have proposed, to take advantage of the above ideas, but without requiring the guide to be fixed to either part, it remains free-floating, with a gap to the hammer adjustable by the red adjuster.... Both versions require the sliding collar.... In the first version, the guide remains stationary and the collar slides, like in Gippeto's, requiring no energy to accelerate it, but does not contribute any to the hammer strike.... In the second version, the guide travels with the hammer, while the collar stays still, like in I_like_Irons version.... which requires energy to accelerate the guide, but it gives that energy back as part of the hammer strike....
The versions where the guide stays still at the back don't stick out the back of the gun, but require room inside the hammer to accommodate the guide during the cocking stroke, so the hammer has to be deeper than the stroke.... The versions where the guide move with the hammer don't stick out the back as far as my original version, but require that the back end of the guide, including the diameter of the stop nut, be able to clear the inside of the gap adjuster without interference or hanging up.... Each version will have it's own limitations, advantages and disadvantages.... Some will be suitable in some guns and not others, and vice versa....I hope by showing all the versions in one place that might help clarify their similarities and differences....
I apologize for not including bstaley's suggestion, I have now added it, in the order it was suggested.... I simply missed it when doing this compilation.... It uses the guide rod passing through the hammer, with a gap between it and the valve stem.... The hammer must be shortened by the thickness of the stop on the front of the guide.... The gap adjuster still works the same, but against the end of the shaft, and the preload can be set by moving the stop nut on the guide.... The guide is stationary until struck by the hammer, which then must accelerate the mass of it and the spring before striking the valve.... Otherwise, it has all the same features as the others....
Bob
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hello from Kefalonia Island West Greece,
My -simplified- version of SSG was last month project on a new artemis PR900W (same as Diana stormrider, Mrodair varmint, etc...)
Because of the very small diameter of the central tube, i decide to adjust the travel and the tension of the spring with the two nuts on the end of the inox 3 mm main shaft of the SSG...
Extra pre-tension of the spring is possible, with the new bronze guide of the spring with the "long" head...
A little tricky was the modification of the end cap of the gun, but i did it successfully...
In the beginning i constructed a system with 4 mm shaft, but as it was heavy enough for the spring of the gun, i changed it with a version with 3 mm shaft... Just perfect...
(https://i.imgur.com/Q07XjYs.jpg)
(https://i.imgur.com/i0UvbvU.jpg)
(https://i.imgur.com/9sZITQc.jpg)
(https://i.imgur.com/MYBrzSG.jpg)
(https://i.imgur.com/epqBHVh.jpg)
(https://i.imgur.com/jTvwEYj.jpg)
(https://i.imgur.com/ClcgQL9.jpg)
(https://i.imgur.com/V1vi3kN.jpg)
the final 3 mm version vs the (double weight) 4 mm one...
(https://i.imgur.com/Zn46p1J.jpg)
(https://i.imgur.com/7ok7Vbf.jpg)
(https://i.imgur.com/qBM5Wfg.jpg)
(https://i.imgur.com/YWql9WC.jpg)
(https://i.imgur.com/ElsXU4h.jpg)
In this tiny gun i have just finished a very light carbonfiber/PVC foam stock... Remains only to put a mat varnish on it...
(https://i.imgur.com/i97aEEv.jpg)
1748 grams for the complete gun including the 4x32 scope... :D :D :D
(https://i.imgur.com/hKtwbLu.jpg)
PS. thanks a lot for the great idea... the gun is easily tunable from 6 to 15 fpe with very nice shot count...
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Nice SSG implementation - great workmanship. 8)
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Very unique the CAM / BAYONET type end cap mounting. Creative to say the lease and a great ideal to make a serviceable system work with what you got !
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Spring has sprung and warm weather is soon to be upon us.
Perfect weather to pull my 2400KT out of hibernation.
But first it's time to replace the power adjuster with an SSG.
The first version was a rear cocking SSG that worked fine.
I wasn't happy with the exposed hardware especially when cocked.
So made this version with a retracting knob.
It uses the stock 2400KT hammer spring and only takes 5 1/2 lbs of cocking effort.
Has a 30 gram mini hammer and the knob is 1" long.
Remove the rear breech and trigger frame screws and the whole enchilada slides out (but you can't eat it).
The tail section will be trimmed when the final version is produced.
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Let me understand.... The knob is on a shaft threaded into the hammer, or sliding through it but able to pull it back?... It stops when it hits the brass rear cap, or?.... There is a tube sliding over the shaft with two lock nuts and the red bumper.... Do they adjust the lift of the valve, and/or the spring preload?.... Is the knob back while the gun is cocked, or does the rod it pulls back slide through the hammer?.... ???
Bob
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This version is the same as a rear cocking SSG except the shaft is hollow and houses a light spring and rod.
When cocked the light spring compresses and bottoms out pulling back the hammer as usual until it cocks.
When released the light inner spring pulls the knob back into the starting position.
Cocked or not the gun looks identical.
The hammer is machined .030" greater internally close to the front allowing the o-ring to move.
The hammer can slide about .060" on the tube but can be pulled off with a moderate tug.
Also extended the hammer slot so the entire assembly can be moved into the tube keeping the external length short.
Here's the components to clarify.
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OK, so the knob returns forward after cocking, that's cool.... and it hides the tubular guide, even when cocked.... I like that.... The SSG is the tube, threaded on both ends, right?.... The cocking rod pulls that back when the internal spring goes coil bound....
I don't follow the purpose of the front O-ring?.... Does it just pull the hammer back from friction?.... If so, how does that friction affect the hammer free-flight?....
Bob
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Correct the SSG is the tube.
Here's a quick drawing to illustrate.
The o-ring just retains the hammer on the tube but when needed can pulled off, the o-ring compress and releases the hammer.
The hammer floats about .060" in and out as needed without friction to facilitate free flight.
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So that would limit the valve lift to 0.060" minus the SSG gap?.... If you backed out the SSG to adjust the gap to 0.120", the hammer would hit the O-ring before it would hit the valve stem?.... ???
Bob
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So that would limit the valve lift to 0.060" minus the SSG gap?.... If you backed out the SSG to adjust the gap to 0.120", the hammer would hit the O-ring before it would hit the valve stem?.... ???
Bob
Right, I keep the free flight small but it all can be modified to fit a particular requirement.
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I get that, but it severely limits the adjustability of the SSG.... ie larger power changes require changing the proportions, rather than just adjusting the gap....
Bob
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This version has a fixed spring tension, I have an adjustable spring tension version but the knob would be longer.
I wanted this CO2 gun set up for a fixed 10-11 FPE with a short knob.
Here's a version with an adjustable spring tension nut but the trade off is the knob is about 3/4" longer to house the adjustment nut.
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Okay, I have a question about the gap.
I have built a SSG like the original Bob Stern design in a 2240 co2 pistol, it worked great.
Now I would like to build one with the gap fixed. I have read through hundreds of posts to see if there is an acceptable gap to use. Most posts don't specify, those that do will be 0.02 to 0.120" (0,5 to 3 mm).
If I just use 0.06(1,5 mm) would this be limiting in any way?
This is for a 20 FPE M-Rod field target rifle.
I have a 30 gram MDS hammer and I have the reg set to 1500 PSI (102 bar).
Hunter
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I agree, its rare to see the ideal gap mentioned. I personally would use 1 - 1.25mm or .04"-.05", which is sufficient for the majority of pcp's to allow two things, the valve to fully close/stabilize, and for some hammer momentum to decay as it has to travel twice that distance prior to striking the valve again.
Increasing gap requires more hammer strike to generate the same FPE as hammer energy/momentum is lost traveling any distance in free flight.
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Thanks Matt.
Off to the drill press.
Hunter
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That's about right on the gap. The kinda standard when all this started was 0.030", and is what I do. It's also true, you don't want to fight more cocking force unnecessarily with too much gap.
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Thanks Keith.
If this idea works then I guess it will be the seventh type of SSG.
Hunter
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Any gap between 0.030" and 0.125" seems to work just fine.... I have not found problems in testing with much larger gaps, other than you do need more spring force (and get a slightly longer lock time).... However, if the gap is larger than that, you can get differences in hammer velocity shooting uphill or downhill, which is the only real disadvantage....
Bob
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Thanks Bob.
I will try 0,040 to 0,050 ( 1 to 1,25 mm).
Hunter
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I usually find a preload that will give me the adjustment range I desire.... If that results in too large a gap, I then reduce the preload on the hammer spring before final tuning.... With many designs of SSG, the gap is easier to adjust than the preload (in many designs that requires removing the SSG from the gun).... If you wish a wide adjustment range, you may have to accept a wider range of gap.... If you are aiming for a single purpose tune, then you can adjust the preload to achieve that at your desired gap.... Too small a gap can waste air because you are still getting some hammer bounce (and often a louder report).... Too large a gap can produced the aforementioned velocity change with gun attitude, and will make the velocity more sensitive to any hammer drag....
Insufficient preload on too stiff a spring can result in increased hammer bounce and cocking effort.... Generally the higher the preload, the lower will be the maximum cocking force, and the greater the resistance to hammer bounce (which is the reason for using an SSG in the first place).... That is why long, soft springs with considerable preload are the preferred choice for an SSG.... Failure to follow that design philosophy is the most frequent reason for shooter giving up on the SSG concept, and any comments you read on them being "too hard to cock".... A properly designed SSG will be easier to cock than any conventional preloaded spring (or indeed SSS), producing the same FPE.... Unfortunately, on some PCPs, there is not enough room to accommodate a longer, softer spring....
Bob
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SSG, TSS, SSS (spring top guide, twin spring system, short stiff spring) all set up in free flight are referred to commonly as hammer de-bounce devices or hammer bounce eliminators, but they don't really eliminate bounce in any sense that serves importance. With a nominal gap, you will still exhibit a successive 2nd and 3rd strike where the effectiveness of your design proves functional or not as to reduce the hammer energy upon those strikes enough to prevent opening the valve...
There is no specific spring rating one must adhere too, but having too 'soft' of a SSG where the spring is easily compressed by the hammer returning to it upon valve closure, is counterproductive. I find having 3-4 lbs of preload minimum on the spring while uncocked is plenty to do the job for most pcps, while some operating at higher pressures with larger poppets may want closer to 5-6. You can achieve this via short stiff springs or long soft springs, what ultimately matters is how its setup when in use. SSG Design, and the rifle its designed for can have limitations to spring length so this shouldn't deter you. As short and stiff are both subjective to a degree, whats short for one setup wont be for another, whats stiff for one person won't be for another...so I like to use the 3-4 lb of preload rule. Easiest way to achieve this is ensure your spring length is a bit under the length allowed on your SSG, to ensure its always under preload. You can achieve this via spacers if necessary or design this feature into the SSG otherwise. I run 1.85" bolts that have a .25" nut/retainer meaning the max installed spring length allowed is 1.6", and I run 2" springs...meaning there will always be .4" preload and at a 7.7 lb spring for me that is 3~ lbs..That spring runs my rifle between 40-65 fpe before being maxed out. My low power 20 fpe tune on the same rifle using a 1.75" 5 lb spring gets roughly .3" preload which is only 1.5 lbs of preload works fine in that low power condition..everything works out merrily with only 1.6" space for a spring to operate...
For comparison here is what it would take to run my valve with a 2.5" compared to the current 2"...not worth the difference.
spring length spring rating starting ending avg
2" 7.7 4.62 10.78 7.7
2.5" 6.2 5.27 10.23 7.75
As stated earlier, only by having the SSG run 'soft' when installed will it lose some effectiveness, which can be done via shorter springs, or longer springs...so ideally you want a spring that's on the lighter side with more preload opposed to a spring that's on the heavier side with zero or minimal once installed and in use. This is because the valve stem has enough energy upon closure, to send the hammer back into the spring and compress it, controlling this via free flight and preload on the spring severely reduces the amount the hammer can re-compress the hammer spring a second or third time.
Proper gap/free flight, and force to compress your SSG (uncocked preload) are primary factors in deciding its effectiveness. How you design around those two factors is entirely up to you.
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Matt,
SSG, TSS, SSS (spring top guide, twin spring system, short stiff spring) all set up in free flight are referred to commonly as hammer de-bounce devices or hammer bounce eliminators, but they don't really eliminate bounce in any sense that serves importance.
Where do you come up with this One statement fits all misinformation ?
A correctly set up SSG with some preload on spring DOES NOT BOUNCE
A TSS or SSS set up I will agree is just a system to control or semi damp the energy created by a bounce.
For the record never been a fan of the latter, but use the former 100 % of the time one can be fitted.
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Okay,
This is for M-Rod 20 FPE FT rifle.
It will have Huma regulator set to 1500 PSI (102 bar).
I have ordered a flat wire spring to use in this mod. It's a Wilson Combat slide recoil spring. It's rated at 13 pounds, but that's with 4 inches of compression, so that's 3,25 pounds per inch. I will trim the spring if it's too strong.
I have a 35 gram MDS hammer from Rocker1.
It will be about 40 grams with striker and the pin.
There will be preload on the spring stop, but not on the poppit.
I haven't started making chips yet, so I have nothing to show.
Hunter
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Hunter
Thanks for the info,
I'll be following along to see your results using the flat wire spring,
I started using the flat wire springs in my builds, I love the smooth and very easy cocking effort,
and the way the flat wire spring stacks into a very small length as compared to the standard round wire springs etc.
The standard FWspring will compress into about a total length of 1.030" for 5.5"+ OEM length etc.
When first installing the FW spring, use the total full length if possible, then trim length as needed.
I got the hammer out of my Sentry 705 22 cal, I'll be using a Flat wire spring, in place of the OEM round wire spring,
as I have lots of room/distance to play with etc.
The sentry has a power adjuster knob which increases the tension on the hammer spring,
so I'll see how the FW spring works, after I figure out the poundage rating of the OEM spring............ ;)
Thanks,
Don
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Scott, I think what PikeP is saying is that the hammer still bounces (it rattles around in the gap), but a properly set up SSG prevents enough energy from being stored in the hammer to reopen the valve.... A TSS or SSS starts with zero preload in order to achieve a gap, and it is easy for the rebounding hammer to compress the spring, which may (or may not) give it enough return energy to reopen the valve....
When I refer to preload in an SSG, I am talking about preload against the stop on the guide.... NOT the valve stem.... That can only occur with an SSG if it is set to zero (or negative) gap, which defeats the whole purpose.... The amount of preload required depends on the hammer mass and travel.... While 3-5 lbs of preload is plenty for a 50 FPE PCP, let me assure you that it is not enough for one producing 500 FPE (unless it has a balanced valve).... The amount of preload is related to the total cocking force required....
Bob
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Don, (NvReloader) thank you, I would never have figured out to use slide recoil springs if not for your thread here:
https://www.gatewaytoairguns.org/GTA/index.php?topic=152501.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=152501.0)
Are you using sbrower's method to measure the spring rate?
https://www.gatewaytoairguns.org/GTA/index.php?topic=152501.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=152501.0)
Hunter
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Hunter
Thanks, If I can find that tool again, I'll use it on the OEM spring,
there was a spring rating guide all you had to do was enter the info,
and you got a rating of the spring, and I can't find that spring calculator right now............. >:(.
I'll have to set up the hammer and check the spring travel limits etc, and get a FW spring etc,
first I have to deburr and polish everything etc, very rough, crude and sociably unacceptable etc.
Thanks for the info on those posts, saves me spending 1/2 day attempting to find them,
I'll save them, now.
Thanks,
Don
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Scott, I think what PikeP is saying is that the hammer still bounces (it rattles around in the gap), but a properly set up SSG prevents enough energy from being stored in the hammer to reopen the valve.... A TSS or SSS starts with zero preload in order to achieve a gap, and it is easy for the rebounding hammer to compress the spring, which may (or may not) give it enough return energy to reopen the valve....
When I refer to preload in an SSG, I am talking about preload against the stop on the guide.... NOT the valve stem.... That can only occur with an SSG if it is set to zero (or negative) gap, which defeats the whole purpose.... The amount of preload required depends on the hammer mass and travel.... While 3-5 lbs of preload is plenty for a 50 FPE PCP, let me assure you that it is not enough for one producing 500 FPE (unless it has a balanced valve).... The amount of preload is related to the total cocking force required....
Bob
Bob,
I'm well aware preloading an SSG equipped hammer against the valve stem is counter productive. Matt and the statement made does not state that but eludes too all three SSG, SSS or TSS don't really eliminate bounce in any sense that serves importance. and that i absolutely do not agree with. I'm not reading between any lines here .... It is a statement for making HEADLINES of some new unknown story, but is in reality IMO a TROLLING statement.
For those who know better, followed the R&D and used said devices now for several years see right threw this slippery attempt to discredit known cause and effect of reduced hammer bounce devises. Or lacking in knowing the differences of each ignorantly stating there all the same.
I stand by my opinion of this unwavering.
Scott S
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I agree, the part you put in bold is not true, I was giving him the benefit of the doubt (the hammer still bounces and rattles around, it just doesn't make any difference).... The SSS can reduce bounce, I have no experience with the TSS, but the SSG is far superior in preventing HARMFUL bounce where the valve reopens, when properly designed and adjusted.... and it does it with a lower maximum cocking effort.... The key is the preload of the spring against the stop on the guide....
We are on the same page here.... ;)
Bob
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Hunter, you should be good with the lower tune and have great results with an SSG. I am not sure which SSG design you have decided on, there are plenty to select from. It's true though that the more spring you can fit within the confines of the allotted space, the less the cocking force required. I designed a captured SSG for my Marauders so there would be no change to the look of the gun, and could adjust pretty much like stock adjustments.
However, for me, I found the original TSS system was the cats meow for the best ES using twins springs with all of the space available for the longest springs. Plus the fine tuning is endless with being able to adjust both the inner and outer springs. I custom cut my springs for the tuning range I wanted, and to allow for a gap within that range. I have had the TSS system in both my Marauders since. Unfortunately, unless you make one, that isn't an option anymore. Also, I would never consider the 2nd generation TSS design. The best part of the TSS was removed in that version.
A lot of input about these mods, but one must add that a lot is dependent on the pressure behind the valve. Many are different thus the setups are different. At any rate, it's true that one can gain up to a 50% increase in shot count if installing one of these to gain a gap in an already poorly tuned gun with preload applied to the valve. Far less when adding to an already properly tuned preloaded setup.
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rsterne,
I´ve made the "floating guide SSG" for the Benjamin Maximus, but I just realized how important is the spring pre-load now, after rereading this finals posts a lot.
I´m using the disco hammer spring now, but I´m concerned about spring losing its size and strength. I left the 1377 spring compressed for about a week or so, while testing the SSG and I've found out it was completely without pre-compression. The 1377 spring shrunk.
So, what kind of wire material should the spring be made of? or you guys just make the pre-compression before a shooting session and then decompress the hammer spring?
Eduardo
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SSG devise and the spring used ALWAYS stay under compression at the assembled pre-load. Cocking the action takes most springs a tad shy of coil bind.
Quality high carbon springs I never had issues with sacking out or failures.
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Before you use ANY hammer spring, simply "set" it to remove any possibility of it getting shorter with use.... Slide the spring over a rod, and using two nuts or collars, press on the ends of the spring to compress it fully, until the coils are touching (coil bound).... Do this a half dozen times.... Chance are when you are finished the spring will be shorter than it started out.... What you have done is exceeded the tensile strength of the wire, and permanently reduced the spacing between the coils, shortening the spring....
Contrary to popular belief, springs seldom get shorter in use, once this simple method of setting them is used.... This is because you can never place a higher load on the wire than what you did by setting it.... As an example, the hammer spring from a Disco loses about 0.2" of length when set.... and it takes only being compressed once (even by cocking to coil bind) to make that occur.... Poor quality springs MIGHT shorten further, but I personally have never experienced it with the music wire springs we use.... SET IT AND FORGET IT.... ;)
Bob
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Question,
For the marauder ssg design with bolt through the hammer, should the hole in hammer be a close fit on the bolt or very loose is ok for better sliding forward when hammer released?
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Loose enough so the TILT the hammer receives when cocking it DOES NOT BIND on the bolt it will be sliding over.
IMO this type SSG is the least accurate due too the mass of hammer and its momentum being damped as it strikes the head of bolt needing to get the ENTIRE SSG DEVISE's mass moving before poppet is struck. It works OK, just self contained SSG's and hammer being in independent free flight works better IMO.
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Question,
For the marauder ssg design with bolt through the hammer, should the hole in hammer be a close fit on the bolt or very loose is ok for better sliding forward when hammer released?
As square and as close of a tolerance as you can drill it and it still slide very smooth over a polished SS bolt that is as straight as possible. The less wobble the better.
Also, as much spring space as you can create. Removing the OEM spring adjuster with something that can still adjust the bolt gap is best.
If you are so inclined, search for the F.A.M.E mod I developed. When you start compressing the hammer spring, that also creates more of a tilt/dig between the hammer and the air tube area which causes more galling and harder cocking. This mod will make cocking butter smooth by raising the back of the hammer up off the air tube preventing galling. When done right, the ES will be very impressive as the hammer glides very consistently and smooth making the cocking effort smooth as well.
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Yup, a friend has this type of ssg and I find the es ain’t all that.
The mass of the heavy hammer has to hit and carry forward the bolt.
Has an extra frictional bolt issue to deal with along with the collision and mass moving forward,
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Yup, a friend has this type of ssg and I find the es ain’t all that.
The mass of the heavy hammer has to hit and carry forward the bolt.
Has an extra frictional bolt issue to deal with along with the collision and mass moving forward,
Friends can be a wonderful thing to have, but when it comes to setting up my guns, its got to be me.
The free floating SSG types are know doubt better performers and easier to build, but the type you asked about can work really well, too. The difference is the protrusion outside the gun with those other mods verses the unseen SSG you asked about. I guess you just have to pick your mod or try them both to see which one you like the most overall.
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So now that the SSG has been around for nearly seven years(!) are there any thoughts on what would be the best design? I built one back then (Super easy, barely an inconvenience!) with a challenger RVA and a bolt, basically Bob's original design. Quoting Bob, the "guide absorbs energy but does contribute to strike." While my brain tells me this would mean the design theoretically requires a slightly heavier spring or more preload, I would think the difference would be negligible, compared to designs where the guide does contribute its energy to the strike. Is this assumption correct? I have been out of the hobby for some years but am about to rebuild my frankengun and am wanting to see if there are any developments in this arena I should be aware of ...
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So now that the SSG has been around for nearly seven years(!) are there any thoughts on what would be the best design? I built one back then (Super easy, barely an inconvenience!) with a challenger RVA and a bolt, basically Bob's original design. Quoting Bob, the "guide absorbs energy but does contribute to strike." While my brain tells me this would mean the design theoretically requires a slightly heavier spring or more preload, I would think the difference would be negligible, compared to designs where the guide does contribute its energy to the strike. Is this assumption correct? I have been out of the hobby for some years but am about to rebuild my frankengun and am wanting to see if there are any developments in this arena, I should be aware of ...
I settled with the original version of the TSS (Twin Spring System) for the best efficiency, fine tuning, performance and consistent ES after many SSG trials. The TSS replaced the final design of my own DIY SSG shown in the first photo which did quite well, but I found the TSS offered up a tighter and more consistent ES.
In the last two photos showing the TSS you can see a larger main spring with its own adjustment and a smaller inner spring with its own adjustment while the MDS hammer is still free floated. The springs are custom cut. The main spring is cut to allow a gap between the hammer and valve while leaving full thread adjustment and being flush with the end cap. The inner spring is custom cut to also allow for a gap and for fine tuning and for its bolt adjustment to sit flush with the locking nut (not shown) so I can use my thumb to pull the cocking bolt back.
There is a setscrew in the end cap and a locking nut on the bolt to lock these two spring adjustments down after tuning. I have the TSS system in both of my Marauders today and they work and hold up very well.
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What I don't like about the TSS (at least the one I have) is that there is no adjustment to the outer spring. The one I got was meant for a P-Rod it looks like. My guess is that with the Marauder having a larger diameter tube, it allows for adjustment of both springs. Also, since I am doing this on essentially a Disco platform, I would also have to drill and tap holes in it to mount it into the tube. That said, I have never tried my TSS, as the gun has been apart for years. I will likely tinker with that as well.
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What I don't like about the TSS (at least the one I have) is that there is no adjustment to the outer spring. The one I got was meant for a P-Rod it looks like. My guess is that with the Marauder having a larger diameter tube, it allows for adjustment of both springs. Also, since I am doing this on essentially a Disco platform, I would also have to drill and tap holes in it to mount it into the tube. That said, I have never tried my TSS, as the gun has been apart for years. I will likely tinker with that as well.
I am not familiar with the Prod but possibly what you may have is the newer revised version 2 of TSS. The second adjustment was eliminated in the version 2 to simplify it. Travis would know the particulars on these as he is the mastermind behind the TSS system. I am very fortunate to have two of the original Marauder TSS versions.
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Hi Friends - In an effort to reduce the hammer bounce in my 2260 I was attempting to build an SSG described in post #637 as it was the simplest and I thought I could use a cap from a 2300 power adjuster.
I gathered parts as best I could off the shelf from my local chain hardware store bins. Once I got it all home I had some trouble getting the length right and so on.
It was in my search of spare parts in the garage that I thought of the method of using the o-rings to soften the blow at the valve. Then I found a spring left over from a repair to my sprinkler system air breaker...
I brought the spring to the gun and it fit the tube - then I eyeballed the fit on the valve and found that if I cut the spring exactly in half it might do the trick. Out came the dremel and the spring was cut. If it turned out to be too stiff I was going to cut it back in small increments but this wasn't necessary.
I assembled the parts back together and gave it a test - the Brrrrt was gone and while it may not be 100% gone, it certainly is reduced to a level that bears testing. I hope to get some range time in before I go to work today and focus on round count rather than FPS,etc.
I had already cut approx. 1 full coil off the hammer spring so I'm using it. I also did the set screw mod to the trigger group - No other mods to gun have been made. The valve is in OEM condition with an unknown round count as I bought the gun second hand.
The spring is 3/4" dia. and 1" long - it feels quite stiff for airgun use but when you cut it down it seems to work well if not perfectly. The parts kit cost me about $15 shipped from HD and like I said, this was a spare left over from a repair. I'm sure a single spring can be had for less at a good hardware store. Still, for about $15 and no other mods, this might be a solution that folks without access to machine shop tools can use to increase performance on a budget.
Here's a link to the parts list for my sprinkler:
https://www.watts.com/products/plumbing-flow-control-solutions/repair-kits/rk-800m4/rk-800m4-v-1 (https://www.watts.com/products/plumbing-flow-control-solutions/repair-kits/rk-800m4/rk-800m4-v-1)
I hope folks find this helpful. I'll report back when I get some testing done.
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And some trimming needs to happen - no piercing of the air cartridge...
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Finally got back to this.
I cut 1/2 coil off and round count went from "some" to "I lost count after 50" Good enough for me.
I did figure out I have a bent barrel though so that was fun.
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This just in - Don't try this, waste of time, effort and energy.
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I'm gonna disagree...respectfully. ;) Almost a standard piece of any build or re-build now...pretty much a "must have" with a balanced valve too.
(https://i.imgur.com/NX525rll.jpg)
(https://i.imgur.com/VdgvR1yl.jpg)
(https://i.imgur.com/VgMnyMml.jpg)
(https://i.imgur.com/Q0GyOiOl.jpg)
(https://i.imgur.com/dNv1WWBl.jpg)
Al
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Alternatively one could build around hammer bounce and have the gun cock itself after each trigger pull or become a semi auto action (marauder semi auto uses hammer bounce to provide semi auto function)
Either way when done correctly I must agree with Gipetto, the SSG is a must in any build that is not using hammerless or hammer bounce semi auto functions