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All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Topic started by: Motorhead on December 07, 2020, 03:07:35 AM
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My JSAR Raptor Mini that I shot Field target with all of the 2020 season fitted with a .20 cal barrel got changed back to more factory spec with a balanced valve while being fit with an LW 22" barrel in .177 caliber. Having been tweaking on this for a couple months now playing with heavy pellets ( JSB Monsters and Beasts ) along with the now obsolete ( H&N Sniper magnums ) in the previous fitted 22" TJ's barrel have switched over to a LW conventional rifled W/choke barrel.
Shooting NSA 15 grain .178 slugs today at 50 yards benched on bags front/rear shot this group ( Just shot it and not a select to show group either )
WHOA ... It shoots !!! ( 10 shots each target )
The right side the lighter 12.5 NSA that obviously does not like going that fast & actually never has made a tight group like the 15's do consistently.
Scott
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That gun looks super slick!!! Mine is set up similar and getting same results! Can’t wait till spring buddy!!!
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Alrighty then; nice work, Scott.
Makes me wonder how my next Leshiy barrel will like .177 NSAs. Yeah, I'm ordering an un-choked .177 barrel :D If Sniper Mags are considered obsolete, it is gonna change up pesting for 3 of my current airguns, so I think I might be placing an order with Nick soon.
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My JSAR Raptor Mini that I shot Field target with all of the 2020 season fitted with a .20 cal barrel got changed back to more factory spec with a balanced valve while being fit with an LW 22" barrel in .177 caliber. Having been tweaking on this for a couple months now playing with heavy pellets ( JSB Monsters and Beasts ) along with the now obsolete ( H&N Sniper magnums ) in the previous fitted 22" TJ's barrel have switched over to a LW conventional rifled W/choke barrel.
Shooting NSA 15 grain .178 slugs today at 50 yards benched on bags front/rear shot this group ( Just shot it and not a select to show group either )
WHOA ... It shoots !!! ( 10 shots each target )
The right side the lighter 12.5 NSA that obviously does not like going that fast & actually never has made a tight group like the 15's do consistently.
Scott
Those are some great looking groups Scott! What speed are you running those slugs at now?
Alrighty then; nice work, Scott.
Makes me wonder how my next Leshiy barrel will like .177 NSAs. Yeah, I'm ordering an un-choked .177 barrel :D If Sniper Mags are considered obsolete, it is gonna change up pesting for 3 of my current airguns, so I think I might be placing an order with Nick soon.
If they are using the Alfa Precision barrel in the .177, I suspect it will like slugs :D The question will be which Alfa barrel, because they offer a polygon and a standard rifled barrel at two different twist rates. Both of which, are faster twist than a LW. After Edgun West gets their next barrel order, I will have an Alfa blank or two to play with myself ;) Alfa is sending a couple blanks with EW barrel order for me :D
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as the pic states in ink pen ... the 15's are at 960 fps
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as the pic states in ink pen ... the 15's are at 960 fps
Sorry, I didn't zoom on the picture :-[ Those are great results just the same, and they will certainly pay dividends when stretching the range over pellets!
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One last Test / Change
Just received a New LW .551" standard .177 no choke barrel and fitted it at full length ( 23 3/4" )
Doing some testing with the JSB 16.2 grain BEAST pellet, regulator at 2300 psi we're throwing them out at 1030 fps !! for a whopping 38 fpe !!
Shooting at my 80 yard play range able to hit the walnut size stones at will with correct dope applied.
Slugs shoot pretty well threw it, but the choked standard seems to be a tad more accurate with them. This Non choke with the super long and heavy 16.2's is a BEAST !!!
Come on spring squirrel season !!!! Pesters ice pick is ready and willing ;D ;D ;D
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That's good stuff!!
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Weather was good enough to go out for an hour or so and unload 9 magazines ( 14 shots per being 126 shots ) using 16.2 beasts and 15 nsa's out at the 80 yard range. Speeds running @1060 This on a SINGLE FILL at @ 4200 psi fill on a 480 bottle. Efficiency crunching at @ 1.48 fpe/ci ;D
Testing the 15 nsa's they do a lot better than the 12.5s as had been the case out of the choked LW standard. At this point i'm so chasing crumbs of data and the sorting of less than or greater than it is getting silly :-[
At this point going to say .. GET A HIGH POWER .177 sorted out you have one h e l l of an air weapon in the world of air guns .... fact !!
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Weather was good enough to go out for an hour or so and unload 9 magazines ( 14 shots per being 126 shots ) using 16.2 beasts and 15 nsa's out at the 80 yard range. Speeds running @1060 This on a SINGLE FILL at @ 4200 psi fill on a 480 bottle. Efficiency crunching at @ 1.48 fpe/ci ;D
Testing the 15 nsa's they do a lot better than the 12.5s as had been the case out of the choked LW standard. At this point i'm so chasing crumbs of data and the sorting of less than or greater than it is getting silly :-[
At this point going to say .. GET A HIGH POWER .177 sorted out you have one h e l l of an air weapon in the world of air guns .... fact !!
That is stellar efficiency Scott! Also, I COMPLETELY agree about getting a high power .177 sorted out. They are so fun, and capable of so much more than people think a .177 can do! It has become one of my favorite calibers now. With that much power and shot count, the critters won't have a chance when you're outside :D I'm still playing around with my Alfa Precision barrels, and have only machined the 14.6" twist so far. It kicks butt with 23 and 24 grain slugs, but I couldn't get it dialed in for the 12.5/15 grain(no surprise). I look forward to seeing how the 16.5" twist barrel does. I think that one will be in the wheel house for the 15-21 grain slugs.
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Scott does the choked LW barrel you have the 1:17.7 twist? And is there a big difference from Nick's hand pressed ammo compared to the new high speed press? Great shooting!
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I have been waiting for quite some time now to get the .172 barrel fitted to the Impact because I’ve been waiting on an HP mold to become available from NOE. This post has pushed me over the edge. I got the regular FP mold the push pins and bushings from NOE on order. Now I just need a bit of lathe time to finish up the barrel. I really hope the impact has enough to push the little ice picks at speed.
Great thread Scott.
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I have been waiting for quite some time now to get the .172 barrel fitted to the Impact because I’ve been waiting on an HP mold to become available from NOE. This post has pushed me over the edge. I got the regular FP mold the push pins and bushings from NOE on order. Now I just need a bit of lathe time to finish up the barrel. I really hope the impact has enough to push the little ice picks at speed.
Great thread Scott.
Nice! I'd go that route as well if they had the 26 grain molds available, 24 grain just looses too much in BC. Do those bullets fit the Impact magazine? Your AR6 has long enough magazine for those bullets.
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Scott does the choked LW barrel you have the 1:17.7 twist? And is there a big difference from Nick's hand pressed ammo compared to the new high speed press? Great shooting!
yes BOTH my original Choked and new Unchoked are 17-7 twist. As too Nicks original hand pressed slugs, Only purchased a single sampler box of 100 ea to see the feasibility of weather or not I could create the power required ? Only fooled with the 15.5's and a few of the 18's but nothing done for accuracy defining testing.
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I have been waiting for quite some time now to get the .172 barrel fitted to the Impact because I’ve been waiting on an HP mold to become available from NOE. This post has pushed me over the edge. I got the regular FP mold the push pins and bushings from NOE on order. Now I just need a bit of lathe time to finish up the barrel. I really hope the impact has enough to push the little ice picks at speed.
Great thread Scott.
Nice! I'd go that route as well if they had the 26 grain molds available, 24 grain just looses too much in BC. Do those bullets fit the Impact magazine? Your AR6 has long enough magazine for those bullets.
Sorry Scott , not trying to hijack the thread. I did attempt to fit the barrel liner to the K550 but gave up on the magazine and the whole idea of shooting from the magazine , it was just beyond my capabilities. I’m hoping they fit the magazine in the impact at their point. If they don’t , I have a few tricks up my sleeve.
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One more Test / Change made that surprised me !!!
Complex subject but will condense it to make sense with minimal rambling on etc ...
Been using a balanced valve able to get big power .. tho it was taking 2350 psi reg set point.
Using the same valve body REMOVED the balanced guts, then installed a conventional poppet ( Cobra type )
* this required going to a much heavier hammer and spring to make equal power ..... THO MAKES EQUAL POWER AT 1800 psi !!!
The 550 psi lower set point buys a bunch of shots !! and in crunching efficiency #'s it still looks very near 1.5 fpe/ci which is very welcome.
Moral being ... The balanced valve ( My version anyhow ) chops the dwell so swiftly it takes more pressure to do the same job as a conventional poppet design can do at lower pressure. * The air bleed hole and path/size in a balanced valve ( JSAR type architecture ) if too large and fast filling attribute to this finding best i can wrap my brain around it. They work, but are so complex on cause & effect tuning there not for everyone and starting to realize a VERY Specialty valve configuration. Worth it ??? I'm starting to conclude for many applications outside Big Bore and efficiency don't matter they may not be worth the trouble ?
Much more here .... but the basic findings these past few days.
Scott S
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Interesting thoughts Scott! I gotta say, this came out of left field to me. I never would have guessed you'd move back to a conventional valve given the low cocking force of the balanced valve? All of this time, I've been thinking how nice it would be to make a balanced valve for my guns, since they are direct pull bolts. If they were side lever, I'd probably care a lot less. The cocking force isn't that bad at the "medium" power levels I usually keep them at, but it can be a bear when I tune them for heavy hitting applications.
I can see why you did it though. Especially, on that gun with the tune you're running. It always interesting to me to see the different ways of doing the same things. I'm always watching/learning from all these different approaches and the experiences of others ;)
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Didn’t see that one coming. Though I’ve come to the same conclusion in regards to the balanced valves. For me they are too difficult to master the minor details to have them work the way I want them to. Ive made a few but the lack of adjustability across a wider pressure range made me to the twin hammer spring or SSG and “cobracoventional” valve layout. For huge power , the Cothran valve is the only valve I’ll use , his machining quality can’t be beat.
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That was unexpected.... Though quite fascinating; I would not have thought that an unbalanced valve could give equal power at that much lower PSI... Especially with those tiny slugs.
Thanks for passing on the info,
Jesse
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On this subject being a few of you are following ....
I'm still using 2 balanced valves in the .22 bottlerauder and the WAR .30 cal and they work fantastic !!
As to the .177 and a balanced valve, it too works great and I'm quite sure I could fine tune it better ??? I know what to do ... that being reduce the venting size threw stem or at least orifice a choke entering balance chamber. OR ... increase the balance chamber volume.
*Either miens would slow down the balance chamber fill speed and lengthen the dwell time.
Whats killing me with the .177 is the valves throat is huge at .280" which processes huge air volume. The "Back up" of air exiting being choked down to .177" creates a lot of pent up energy ( Pressure & volume not exiting ) that amplifies the signal / air passing into the balance chamber. This causes the chamber to pressurize super fast & having a light hammer being moved via SSG being in free flight .. CLOSES lightning quick !!!
* This effect is less pronounced as the caliber increases with the same @ valve specifications. Why in .22 and .30 cal I can run at 1800-2000 psi set point and get all the power wanted and the "TUNE" is less touchy.
Digesting the above ... This is why I'm seeing a HIGHER PRESSURE required when using the balanced valve. The Dwell being so short is requiring more energy gained by pressure & not volume to get the power wanted. Running a conventional poppet ( Cobra ) it operates more linear being held open for longer dwell based off hammers increased weight/mass primarily. The "Cobra" air spring just nudging the poppet to close just a bit quicker tho Not slamming the poppet closed as balanced does with a lighter hammer. This has the system utilizing more volume of air at a lower pressure which in total near equals the displaced total energy by valve, just distributed in a differing ratio open to close.
Hope this is making some sense.
Scott S
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Interesting findings on the balanced valve vs. Cobra. I believe there are so many variables with balanced valves it is very difficult to optimize for a given application.
I have been a big fan of the Cobra valve ever since your "demystifying" thread. I have Cobra valves running in guns that produce from 25fpe to over 300fpe.
So far, I like balanced valves when: 1) wanting a higher ratio of FPE to required hammer strike 2) wanting to manage ES across a broad unregulated pressure range, at energy levels that require large for caliber porting, thus taking away the tuning tool of choking the transfer. Note neither of these are max-energy applications.
Another item I will add around balanced valves---at least in my testing, significantly oversized throats hurt tuneability.
I like versions of the Cothran for many applications. But for max energy in calibers above .300, the Cothran just cannot flow enough.
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Balanced valves can be a bit tricky to find the right balance characteristics.... The smaller the balance chamber and the larger the vent, the more the valve acts like a conventional valve, except that it is easier to crack open initially.... I made a balanced valve for my .357 cal Hayabusa (throat = 0.375"), and then went progressively down all the way to .224 cal just by installing a tapered transfer port and adjusting the hammer strike.... For the .224 cal (107 FPE) and .257 cal (136 FPE) I used a 77 gr. hammer with 1.09" of travel.... For the .284 cal (177 FPE), the .308 cal (200 FPE) and the .357 cal (248 FPE) I used a 113 gr. hammer with 1.18" of travel.... All used the same hammer spring, with various SSG gaps, and all these tunes were tethered at 3000 psi.... They all ended up with similar efficiency of about 1.15 FPE/CI.... This valve still required a fairly heavy hammer, because I used a small chamber and larger vent, to make the valve easier to tune by varying the hammer strike....
If I had used a larger balance chamber and/or smaller vent, the valve would have had more tendency to "blow open", and required less hammer strike.... However, it would have been much harder to tune, with more of a "plateau and cliff" reaction to SSG gap, like a Cothran valve (I had a valve like that initially).... That wasn't what I wanted, and after the changes what I got was a valve that would work over a huge range of calibers and power settings.... I never found that I needed increased pressure on any of the calibers, compared to the conventional valves I originally installed.... They all retained, or exceeded, their original performance at the same pressure.... I sacrificed a heavier hammer strike for increased tunabilty.... but still a much lighter strike than with a conventional valve....
Scott, regarding your findings, perhaps a heavier hammer would resist the blowing open of your valve, and increase dwell and tunability?....
Bob
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Indeed a heavier hammer would exhibit a tad more hang time at full travel of poppet open stroke buying a tad bit of dwell time.
and at the same time likely allow a tad less hammer spring tension or lessor spring rate affording even easier cocking ....
Yea a WHOLE LOT of small tweaks to find little gains ....
As to the tuning aspect, it tunes wonderfully over a very broad range ... issue I'm having is .177 cal specific when really leaned on for power.
* With the balanced valve and hammer it had, set with a consistent HST within the SSG device, Dialing in more pressure on the external regulator the power ramps up as pressure increases very linear ;)
Issue tho being to get the power I'm shooting at and the base line for the valve change is it took 2350 PSI in balanced form and only 1800 psi unbalanced.
This chase is WHY I'm not able to get equal power running balanced at 1800 psi ? ...... I'll try more hammer weight and see if that helps with all else where it was :-\
My having fun with this is kinda getting old.
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Do I understand correctly that you are running about 38 FPE with this gun?.... on a 22" barrel?....
Bob
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Do I understand correctly that you are running about 38 FPE with this gun?.... on a 22" barrel?....
Bob
Of late with the above fiddling YES tho on a 23 3/4" LW standard non choke 17.7-1 twist.
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Ok ... I'm so done fiddling I'm going to stop and run it as is ... THAT BEING, back at balanced with a hammer @ 12 grams heavier !!!
Sure as heck Bob was correct that more hammer weight was all that was required ;D
Back at 1800 psi with the heavier hammer, choked transfer port as previous ... THO slightly backed off on SSG spring preload it is now making the same power as the conventional valve ( Same hammer actually ) tho much lighter SSG spring fitted.
I need a new gun project !!! taken this poor JSAR apart sooo many times !!
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There is no reason that a balanced valve should need more pressure for the same performance.... Vice versa, there is no reason it should perform better, unless the gun is limited by hammer strike with a conventional valve.... Glad you got it sorted, Scott.... 8)
You know what the old saying is.... If you can't fix it, get a bigger hammer.... ::)
Bob