A New Method for Increasing the Efficiency of a PCP - the SSG

[triggertreat]

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!

[Buldawg76]

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

[beejwest]

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. 

[Gippeto]

"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

And for a "sorta" QB...



Al

[rsterne]

Very nice, as usual, Al....

Bob

[Buldawg76]

+1 on that Al. I like it and I would say it qualifies on both requirements of " clean and internal " IMO

Mike

[jackpatrick]

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?

[Tomg]

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.

[Tom SC]

Paul you can reach your goal with a regulator and SSG and a stock hammer.

[Motorhead]

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 

[Ribbonstone]

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.

[lloyd-ss]

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

[tinsoldier]

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.



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.



Thanks again!

[Motorhead]

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.

[Rocker1]

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 
[/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

[mobilemail]

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...

[triggertreat]

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.




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. 



I also added a sleeve in the hammer for more surface contact with the bolt to help prevent hammer tilt and improve cocking.



The spring is still adjusted with a screwdriver through the gap adjuster set screw.



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. 

[tinsoldier]

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.

[triggertreat]

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.

[triggertreat]

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.



Here is the tune analyzed for 4% ES:



Here is the tune analyzed for 30 shots with a little tighter ES and includes the detailed numbers:



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.