GTA
All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Topic started by: YEMX on January 21, 2022, 09:30:51 AM
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I can't remember if I posted about this build or not, but just in case I didn't- here we are. Nothing complicated or anything that hasn't been done before...
Condor SS Frame
Green Mountain .172 barrel, 1:9 twist. 1/2-20 muzzle threads. I think it's 24"+. The blank was over an inch in O.D. and was $50. That's why I got it.
Doug Noble internals, mods and top hat
RMPA Precision Trigger
I'd love to pick up an RMPA chassis, but there's no telling when those will come out. I picked up a WokButt for the factory tank strap butt-plate. Most of the rifle modifications are done, and she's actually on her way back here. I just need to finish assembling the rifle and get some time to shoot her!
I actually found a NOE 26 gr. .172 mold, and that's on it's way here as well. I'm probably going to send it off to Erik and have the mold HP'd.
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I have a TJ .172 1-9 that's been in the rack almost 4 years now. I'll eventually do something with it. It's 28"
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I’m considering putting one I’ve got on my pilot valve build. If it turns out to be a 9 twist. But I’d have to cut a mold and other stuff…..
I really just want to see what one of these little pills would do with 4500 shoved up its tail.
Keep us posted on how this turns out.
Dave
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If going to a HP mold you may find it very finicky to cast vs. a solid FN, been casting with a .172 mold that I had opened up and decked to 18.5 gr for my meager .177 slug guns.
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AirForce would be a good test rig….nearly any diameter barrel can be fitted with new bushings. Airforce system can move a whole lot of air without much redesign. While I really didn’t love the style rifle, did recognize what it did well.
Living vicariously….started playing in that direction some years back, lost the shop and the urge...but am interested in your results.
Thoughts then were:
1. Basic physics is against winning an energy race, but could win a trajectory/windage race.
2. Something “stupid” still happens at the transonic area, it’s just not quite the same brand of stupid as with pellets.
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Am with Back-Roads about getting the mold hollow pointed...casting good .172” is hard enough, hollow point (or hollow base) molds make any size bullet harder to cast uniformly.
If we hold pellets to certain standards of uniformity, for accuracy, tend to also hold slugs to pretty tight standards. Reject rate is high, but every HP (or HB) mold works out to an even higher reject rate.
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I really just want to see what one of these little pills would do with 4500 shoved up its tail...
That would be pretty interesting!
If going to a HP mold you may find it very finicky to cast vs. a solid FN, been casting with a .172 mold that I had opened up and decked to 18.5 gr for my meager .177 slug guns.
...Am with Back-Roads about getting the mold hollow pointed...casting good .172” is hard enough, hollow point (or hollow base) molds make any size bullet harder to cast uniformly.
...Reject rate is high, but every HP (or HB) mold works out to an even higher reject rate.
Hmmm, I may hold off on the HP'ing... I'm not that great of a caster as it is. I also don't NEED the projectiles to fragment...
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Unless you have a lot faster twist than 9", you don't need 4500 psi.... My gun is regulated at 2800, and shoots the NOE HP's over 1000 fps....
Bob
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Yeah, guess I’ll just forget about it….
Dave
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Those NOE pills are great, and I have no doubt you can do a mold for a 3 caliber long BBT, which should be great in a 9" twist.... Your valve would work great in a regulated PCP, so why not?....
Bob
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I’ve got a barrel that iust won’t shoot the NOE 24 grain as cast. They are a tad on the small size for the barrel. I’ll revisit it at some point but for now it sits and waits . Good luck with your build.
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Yeah, guess I’ll just forget about it….
Dave
Dave you never responded to my .172 barrel offer. did you have one barrel in .172 already?
If so, i can send ya a few hundred 26 grains to test.
I know i got mine going 63fpe in a FX Impact. they were doing 2 inches at 100. not good yet. But it was a 10mm straw and my castings aint that perfect.
I got it in a 20cc regulated airforce clone from artemis. 200 bar, 970fps with 26grains.
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I’ll pm you Duy, don’t want to derail Y’s thread here.
Dave
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No worries about derailing anything gents- I like when my threads have a life of their own. As long as discussion sticks to .172 builds/casting, I'd like to see where the thread goes.
I've been itching for another stock project- I think I'm going to knock up a drilling jig for the necessary holes for the AF frame, and I'm going to finish making my router table. I really like RMPA's proposed chassis, but there's no telling when it's going to come out (Texan chassis first), and Maddog Stocks don't quite have the design I have in my head (absolutely no knock on him!). So I'm gonna have another go at making a chassis. My first attempt was okay, but there's a LOT I have learned and would change.
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Those NOE pills are great, and I have no doubt you can do a mold for a 3 caliber long BBT, which should be great in a 9" twist.... Your valve would work great in a regulated PCP, so why not?....
Bob
Because my desire was to utilize the higher pressure capability. It’s obvious that would take a really fast twist/heavy pill. Which is difficult to find and $ for an experiment.
Sure I could reg it down but then I have other platforms I could do that with. If I stumble on to a faster twist, I’ll get my hopes up again.
Duy is gonna send me some slugs to try in my barrel. I’ll go ahead turn my barrel to fit but it’ll probably go on one of my regged platforms.
Dave
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Sounds like a FUN project. These small caliber Ice Pick shooters are a blast once ya get em sorted & especially if you can get em up near 1000 fps !!
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I've been thinking of building a .172 but the lowish BC of 0.11-0.12 that Bob measured is kind of making it not worth it when I can shoot 0.16 ish BC bullets in 0.224. Is there a .172 barrel / bullet combo that can actually reach 0.16 or higher BC and is it doable without very high pressure? I like the idea of low air usage and small bullets but to justify the expenses it would have to be close to my .257 in ballistics performance.
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I've been thinking of building a .172 but the lowish BC of 0.11-0.12 that Bob measured is kind of making it not worth it when I can shoot 0.16 ish BC bullets in 0.224. Is there a .172 barrel / bullet combo that can actually reach 0.16 or higher BC and is it doable without very high pressure? I like the idea of low air usage and small bullets but to justify the expenses it would have to be close to my .257 in ballistics performance.
I could be wrong, but I don't think there is. I think there's only 2 molds to choose from, both from NOE, and both have been out of stock for quite some time.
I have a 6mm Condor that Doug is putting together for me as well. I have high hopes for that one. But that's another thread.
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Roughly speaking, the BC is about equal to the SD, maybe a bit better for a great shape.... The 24.7 gr. NOE HP has an SD of 0.119, and the BC was virtually the same as that.... So, to get a BC of 0.16 or better, look for an SD of 0.16 or higher.... In .172 cal, that works out to 33 grains or heavier.... Maybe a 30 gr. pill might do it in a Spitzer, with a boattail.... That definitely means you need a twist faster than 9" to stabilize it.... The two longest BBT designs at the top of the page at this link would be the ones to look at....
https://www.gatewaytoairguns.org/GTA/index.php?topic=185897.20 (https://www.gatewaytoairguns.org/GTA/index.php?topic=185897.20)
You would probably need a 7" twist (maybe 8"?) for the 3.5 cal. long design, more like a 6" twist (maybe 7") for the 4.0 cal long BBT.... If you tried for an even longer slug, I doubt you can buy a fast enough twist barrel to shoot it.... Pac-Nor makes .172 cal down to a 6" twist, starting at $300....
https://pac-nor.com/barrels/ (https://pac-nor.com/barrels/)
As a comparison, in .224 cal, the 3.0 cal long BBT weighs 58 gr. (HP) or 60 gr. (FN), and either would shoot in a 10" twist.... The BC should exceed 0.16, and you still only need about 3800 psi to hit 1000 fps.... The longer BBTs would need faster twists, the 3.5 cal long (63-66 gr.) about a 9" twist, and the 4.0 cal long (69-73 gr.) about a 7.5" twist.... A 73 gr. slug in .224 cal would have an SD of 0.208, and should have a BC to match, but you would need 4500 psi in a long barrel to hit 1000 fps with that....
With current PCP technology, the sweet spot for long range shooting is .224 cal to .257 cal, IMO.... Smaller you run into twist availability problems, and larger the combination of pressure and barrel length limits your maximum SD (bullet weight and BC) to get velocities up around 1000 fps.... It's pretty hard to beat a good .257.... ;)
Bob
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I got my NOE .172 mold in today. WHEW!! I had a mental picture of these little devils in m head, but looking at the mold IRL... Y'all weren't kidding, these things are TINY!! I can't wait to start casting them!
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Tiny, yes.... but quite destructive....
(https://hosting.photobucket.com/albums/oo221/rsterne/Ballistics/.highres/172 cal HP at 1050 fps_zpscgg11hoq.jpg?width=1920&height=1080&fit=bounds) (https://app.photobucket.com/u/rsterne/a/ad32680a-7969-443d-ab0e-5a65c7b8979e/p/043be8d2-2391-4ee4-82d3-b8d4c435a845)
That is the HP version at ~ 1000 fps....
Bob
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Tiny, yes.... but quite destructive....
(https://hosting.photobucket.com/albums/oo221/rsterne/Ballistics/.highres/172 cal HP at 1050 fps_zpscgg11hoq.jpg?width=1920&height=1080&fit=bounds) (https://app.photobucket.com/u/rsterne/a/ad32680a-7969-443d-ab0e-5a65c7b8979e/p/043be8d2-2391-4ee4-82d3-b8d4c435a845)
That is the HP version at ~ 1000 fps....
Bob
THAT is the exact reason .172 is so interesting to me! Very small lead expenditure for each slug, and very destructive on targets. I may have one cavity HP'd, and keep one as a solid...
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Yup and you can carry 100 rounds with you without walking lopsided. ;D 8)
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THE .172 IS HOME!!!! Whew! This thing is HEFTY!! I'll post pics when I assemble it. For now, it simply looks like a Condor SS with a longer (and THICK) barrel. It even has a factory metal tank! LOL I did add a WOKButt though. TBH, I think I'm just going to keep it this way and simply shoot it. Not sure what scope I want yet.
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Was finally able to get a WOK Guard for this rifle. I've also got a grip I want to try on this build as well... I hope it'll work out. If not, no biggie. I think the good 'ol Enhanced Vertical Grip by Masterpiece Arms should work, no problem...
I've also got one of those roller bearing triggers by RMP Airguns. I really want one of their chassis, but I have no idea when it's going to be out. Hence why I went with the WOK Guard...
I still have to send my mold to Erik. I've just emailed him again, if I don't get an email back within a few days, I'll give him a call. I have this .172 mold and a 6mm mold I want HP'd.
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Man you are smashing projects this year Tom. Can't wait to see how it shoots.
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Because my desire was to utilize the higher pressure capability. It’s obvious that would take a really fast twist/heavy pill. Which is difficult to find and $ for an experiment.
Sure I could reg it down but then I have other platforms I could do that with. If I stumble on to a faster twist, I’ll get my hopes up again.
Duy is gonna send me some slugs to try in my barrel. I’ll go ahead turn my barrel to fit but it’ll probably go on one of my regged platforms.
Dave
Dave, if you are shooting slugs instead of pellets couldn't you go supersonic with this gun?
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HA!! So I forgot I have a top-mounted bipod, and I'd like to use it. Except it's for a Pic rail... ALL of my dovetail to pic rail adapters are too tall (I feel). So I went on the hunt for a low profile adapter. I found one made my NCStar, which looks pretty low. We'll see how it goes. I don't want it TOO low, because I'm worried I'll loose too much of my cant movement (bipod cants and swivels). I also found a longer pic to dovetail insert adapter. The way the bipod base is designed, I need an adapter that's got at least 3 grooves... So your typical pic to dovetail adapters for scope rings won't work. I feel like if it's TOO low (i.e. with one of these inserts), that I'll lose cant movement. Again, I'm hoping the NCStar adapter is low enough...
Not much of an update, I'll post some pics when I get these parts in and get them on the gun.
I've also ordered a new LDC for this gun from DonnyFL. I wanted something built like a tank, since this rifle will be mostly travelling. It's kind of a different LDC- it's for FX guns apparently- it's similar to the Tanto- except it's got a larger O.D. Tanto is: 1.22"x5" FX: 1.36"x5". It's got 1/2-20 threads. It's $20 more than the Tanto, so $120. I wanted the tank because I feel like the muzzle blast from this build will be pretty brutal (especially over time), and I'm not wanting to buy another LDC any time soon. Also, it's good up to .25. I did want to get the larger O.D., maybe it'll help with sound dissipation over the Tanto. Maybe not though- NOW I notice that the Tanto has dedicated .177/.22 bores, vs the FX one, where it's .22/.25. It's a good thing I don't need THAT much sound suppression since I'll be outside, in a open field ::)
Again, I'll post pics when I get this more assembled.
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Brian, going Supersonic will INCREASE the wind drift compared to keeping it in the 900s.... This is because of the huge drag increase in the Transonic region, which applies to all projectiles....
(https://hosting.photobucket.com/albums/oo221/rsterne/Ballistics/.highres/Wind Drift G1_zps5d7eem8a.jpg?width=1920&height=1080&fit=bounds) (https://app.photobucket.com/u/rsterne/a/ad32680a-7969-443d-ab0e-5a65c7b8979e/p/99eed44d-57da-45ae-aca3-a90187b5298b)
You would have to push a typical .172 slug at about 2500 fps before the drift is less than at 900 fps.... :o
Bob
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Tiny, yes.... but quite destructive....
(https://hosting.photobucket.com/albums/oo221/rsterne/Ballistics/.highres/172 cal HP at 1050 fps_zpscgg11hoq.jpg?width=1920&height=1080&fit=bounds) (https://app.photobucket.com/u/rsterne/a/ad32680a-7969-443d-ab0e-5a65c7b8979e/p/043be8d2-2391-4ee4-82d3-b8d4c435a845)
That is the HP version at ~ 1000 fps....
Bob
Tiny, yet very impressive.
Brian, going Supersonic will INCREASE the wind drift compared to keeping it in the 900s.... This is because of the huge drag increase in the Transonic region, which applies to all projectiles....
(https://hosting.photobucket.com/albums/oo221/rsterne/Ballistics/.highres/Wind Drift G1_zps5d7eem8a.jpg?width=1920&height=1080&fit=bounds) (https://app.photobucket.com/u/rsterne/a/ad32680a-7969-443d-ab0e-5a65c7b8979e/p/99eed44d-57da-45ae-aca3-a90187b5298b)
You would have to push a typical .172 slug at about 2500 fps before the drift is less than at 900 fps.... :o
Bob
2500fps? Wow-wee, that is getting up into high-powered rifle territory. Fascinating, not really practical for an air rifle, but fascinating. Subsonic and Supersonic aerodynamics are so completely different.
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Brian, going Supersonic will INCREASE the wind drift compared to keeping it in the 900s.... This is because of the huge drag increase in the Transonic region, which applies to all projectiles....
(https://hosting.photobucket.com/albums/oo221/rsterne/Ballistics/.highres/Wind Drift G1_zps5d7eem8a.jpg?width=1920&height=1080&fit=bounds) (https://app.photobucket.com/u/rsterne/a/ad32680a-7969-443d-ab0e-5a65c7b8979e/p/99eed44d-57da-45ae-aca3-a90187b5298b)
You would have to push a typical .172 slug at about 2500 fps before the drift is less than at 900 fps.... :o
Bob
Bob your wind drift graph doesn't show wind angle or MPH?
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Correct, but it would have been 90 deg. to track, constant wind velocity from muzzle to target, and likely 10 MPH.... It doesn't make any difference to the relative performance, it is the sideways wind component that matters, and drift is proportional to that.... The point is to show the effect of muzzle velocity on the drift at 200 yards....
Bob
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Correct, but it would have been 90 deg. to track, constant wind velocity from muzzle to target, and likely 10 MPH.... It doesn't make any difference to the relative performance, it is the sideways wind component that matters, and drift is proportional to that.... The point is to show the effect of muzzle velocity on the drift at 200 yards....
Bob
My apologize Bob, I am a first and foremost a hunter and have no interest in shooting pellets or slugs at 200 yards or even 100 yards. I am more interested in the terminal ballistics and the wound/expansion that can be created with a supersonic slug.
I believe that Dave's gun can send a projectile of this size well past super sonic and keep it there well past the distance I would want to hunt with it.
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Correct, but it would have been 90 deg. to track, constant wind velocity from muzzle to target, and likely 10 MPH.... It doesn't make any difference to the relative performance, it is the sideways wind component that matters, and drift is proportional to that.... The point is to show the effect of muzzle velocity on the drift at 200 yards....
Bob
My apologize Bob, I am a first and foremost a hunter and have no interest in shooting pellets or slugs at 200 yards or even 100 yards. I am more interested in the terminal ballistics and the wound/expansion that can be created with a supersonic slug.
I believe that Dave's gun can send a projectile of this size well past super sonic and keep it there well past the distance I would want to hunt with it.
What would you be hunting that requires a 25+ grain slug to go supersonic? The whole benefit of sending smaller slugs super sonic is to retain energy and accuracy at long ranges. I think Bob is trying to say that there is no benefit of sending tiny slugs at super sonic velocities compared to a slightly larger/heavier slug at sub sonic speeds.
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What would you be hunting that requires a 25+ grain slug to go supersonic? The whole benefit of sending smaller slugs super sonic is to retain energy and accuracy at long ranges. I think Bob is trying to say that there is no benefit of sending tiny slugs at super sonic velocities compared to a slightly larger/heavier slug at sub sonic speeds.
Nothing "requires" it. I have killed thousands of squirrels and other small game with a .22 pellet at 850 fps. But why not have the wound channel that a super sonic slug can offer? I am a big fan of over kill.
That's like saying why would I hunt deer with a rifle if my shot opportunities are rarely over 100 yards. A slug out of a shotgun does just as well at that range. I have killed lots of deer with a shotgun slug. I prefer what a rifle can do.
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What would you be hunting that requires a 25+ grain slug to go supersonic? The whole benefit of sending smaller slugs super sonic is to retain energy and accuracy at long ranges. I think Bob is trying to say that there is no benefit of sending tiny slugs at super sonic velocities compared to a slightly larger/heavier slug at sub sonic speeds.
Nothing "requires" it. I have killed thousands of squirrels and other small game with a .22 pellet at 850 fps. But why not have the wound channel that a super sonic slug can offer? I am a big fan of over kill.
That's like saying why would I hunt deer with a rifle if my shot opportunities are rarely over 100 yards. A slug out of a shotgun does just as well at that range. I have killed lots of deer with a shotgun slug. I prefer what a rifle can do.
Are you hunting deer with a .172? I'm just not sure, beyond long range target shooting, what advantage there would be to a supersonic .172 slugs, especially when talking about airguns. I'm really not sure how much different the wound channel on a .172 traveling supersonic vs a 19 grain .22 pellet traveling at 750 - 900 FPS in the context of hunting small game. Maybe it would be useful for shooting Coyote at 100 yards, but at that point I would be switching to larger slugs with better BC values and more retained energy downrange.
I just don't see any advantage to hunting small game with a super sonic .172 slug. There are other applications where I could see it being useful, just not hunting small game.
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Are you hunting deer with a .172? I'm just not sure, beyond long range target shooting, what advantage there would be to a supersonic .172 slugs, especially when talking about airguns. I'm really not sure how much different the wound channel on a .172 traveling supersonic vs a 19 grain .22 pellet traveling at 750 - 900 FPS in the context of hunting small game. Maybe it would be useful for shooting Coyote at 100 yards, but at that point I would be switching to larger slugs with better BC values and more retained energy downrange.
I just don't see any advantage to hunting small game with a super sonic .172 slug. There are other applications where I could see it being useful, just not hunting small game.
I guess we can all agree to disagree. My thoughts apply to Dave's gun anyway. Back to your regularly scheduled program!
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Really have no right to an opinion...didn’t continue with the .172” slug experiments long enough.
But I can (repeat) tell you want I was after.
Trajectory and wind age advantage, energy was just a by product.
Accuracy is always “king”…..but for hitting the mark you are aiming at (paper targets, spinners, or little critters that don’t need much power), there is a high value in less wind age and less exacting range estimation (trajectory)….which is what slugs higher BC slugs do,
Could get the same effect wind age and trajectory with a bigger caliber/heavier slug of the same BC and earn more energy, which is likely what a hunter wants, Didn’t see the energy advantage in “hitting” and inanimate target; should be an advantage in “killing” and animate target.
Same BC slugs (regardless of caliber/weight) at the same speed gives the same trajectory, wind...so same hold… bigger/heavier slugs carries a lot more energy (at the same speed is proportional to weight).
If shooting paper, where is the advantage for an energetic hole in paper? Get bonus points for fiipping a spinner 8 times around rather than just 4? Knocking a gong off it’s chains rather than just ringing it?
Consider:
The air tank/tube contains all the energy you get to shoot from. Each shot subtracts that shot’s energy the total supply of energy. IF 40 foot pound “bites” of energy gives the same trajectory/windage as 80 foot pound bites, should be able to shoot 2X as much on the same air supply.
In the negative category, the smaller the slug, the more small imperfections count against accuracy. Even if you start “perfect”, imperfections can be induced by the act of firing (what exits the barrel may not be quite what was loaded into the barrel).
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OP wont take a picture without full accessory. keep us in suspense and OP thinks without accessories the gun wont look as good?
and i am getting lost in reading ribbonstones explainations. i am guessing accuracy might be affected with increased speed? is that your point? i may agree with that.
for pellethunter. the wound channel will likely look like what Bob showed with the expansion picture. bloody and quick death. its cool to over kill small pests if you hate them that much. but you may miss more due to possible accuracy with super sonic speed even below 100 yards?
I have shot .172 out of my Impact at 1050fps before. the slugs will track in a 3 inch circle down at 100 yards. sometimes hit exactly where i aimed. but sometimes 1-2 inches around the cross hair. i cant hit a squirrel like that. I am pretty sure the wind was pushing it around like that.
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The external ballistics are only part of the story, of course.... Using air (ie not Helium), the closer you are to Mach 1, and particularly if you exceed it, the lower the efficiency.... In other words, it takes a LOT more air to get to 1200 fps than 1000 fps.... and even more to go faster.... The faster you drive the slug, the more air it takes for each FPE developed.... Supersonic, you are likely discharging a greater mass of air than that of the projectile....
The drag in the Transonic range is so large that the slug slows very quickly.... For example, a .22LR high-velocity RN drops below Mach 1 at about 75 yards, which is why the subsonic "target loads" outshoot them at 100 yards.... Add in the report, not only caused by all that extra air exiting the muzzle, but by the projectile itself creating shock waves from being Supersonic, and I see little point in wasting all the air required to get a couple of hundred extra fps, which you will lose before you get to 100 yards, and have more wind drift to deal with as well....
As you said, you are entitled to your opinion, I am just trying to offer you (and others) the science behind staying Subsonic to consider before deciding if it's worth it....
Bob
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for pellethunter. the wound channel will likely look like what Bob showed with the expansion picture. bloody and quick death. its cool to over kill small pests if you hate them that much. but you may miss more due to possible accuracy with super sonic speed even below 100 yards?
I have shot .172 out of my Impact at 1050fps before. the slugs will track in a 3 inch circle down at 100 yards. sometimes hit exactly where i aimed. but sometimes 1-2 inches around the cross hair. i cant hit a squirrel like that. I am pretty sure the wind was pushing it around like that.
That's exactly my point, Bob's picture showed a great wound channel, I want to know what that would look like at 1,500-1600 fps.
I guess my opinion is situational. I have a good size farm and I help manage another large farm near by. I am not usually concerned about shot count as my spare air is in the truck or on the ATV a close distance away. I probably average 10-15 shots at live targets on days I have time for it. My shooting is inside 40 yards. Statistically when you shoot at that many live targets you make human errors or in some situations it's out of your control and you make a bad shot. I would prefer to be packing as much damage as possible when those situations arise and minimize wounded critters. I could do all this with a 22lr but I enjoy airguns and it's almost impossible to find 22lr ammo for sale here.
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"Supersonic" (as in 1200 fps) yes, but 1500 fps with a 25 gr. pill is 125 FPE (and 1600 fps is 142 FPE).... Using my "lofty goal" formula, a .172 cal with a 28" barrel and 4500 psi might get 122 FPE for a single, full power shot.... That is twice the power I am getting with a 28" barrel at 2800 psi, with full bore area porting throughout.... Even if I could manage the same power/pressure ratio (which I know won't happen Supersonic), I would need 5600 psi to get there.... :o
Bob
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We also have a velocity limit to where the soft lead used in slugs will deform and tear or come apart in the rifling. I'm not sure of the proper term for that.
Increased leading of the barrel may also happen at higher velocities.
But I am sure both are related to twist rate and velocity.
Thanks,
Taso
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OP wont take a picture without full accessory. keep us in suspense and OP thinks without accessories the gun wont look as good?
OP as in me? What's the point of taking pictures at this point? It looks like a normal AF rifle w/a really thick barrel. My accessory choices don't really have anything to do with looks- the roller trigger is simply (or rather, supposedly at this point) a better trigger, the new trigger guard both stiffens the frame and allows me to us AR grips, and the LDC is to quiet the gun.
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i am actually curious to see how thick it is. isnt that strange? is it green mountain 1” blanks?
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LOL, patience is a virtue.
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i am actually curious to see how thick it is. isnt that strange? is it green mountain 1” blanks?
Yessir, Green Mountain. I believe it's a 1" O.D. blank. It's also been sleeved in CF, but that was the machinist's choice. I assume for looks, as a 1" O.D. steel barrel in .172 isn't lacking in the stiffness department! I didn't care either way.
The trigger guard should be here in a couple days, and the LDC might be here tomorrow? Regardless- I should have pictures up this week sometime. The dovetail to picatinny conversion rail won't be here for another week :(
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"Supersonic" (as in 1200 fps) yes, but 1500 fps with a 25 gr. pill is 125 FPE (and 1600 fps is 142 FPE).... Using my "lofty goal" formula, a .172 cal with a 28" barrel and 4500 psi might get 122 FPE for a single, full power shot.... That is twice the power I am getting with a 28" barrel at 2800 psi, with full bore area porting throughout.... Even if I could manage the same power/pressure ratio (which I know won't happen Supersonic), I would need 5600 psi to get there.... :o
Bob
We hit our limit pretty fast with airguns dont we? you are pretty conservative on not telling people outright that its hard to get there…
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I have learned over the years not to tell people things are impossible, unless they are.... For instance, the maximum possible FPE for an airgun can be calculated by using the pressure (psi) times the bore area (sq.in.) times the barrel length (in feet), and that FPE is the total, including the energy necessary to accelerate the air released by the valve (the biggest loss).... For my "lofty goal", I use half that, to allow for pressure loss during the shot, friction, the air mass, etc.etc.... but that is only an estimate, and a couple of times it has been exceeded by using a very short barrel and high pressure, or projectiles so heavy that the velocity is quite low.... In cases that have slightly exceeded 50%, there was a lower air mass relative to projectile weight.... The caveat to the 50% "lofty goal" I use, is that the projectile weight is such that the velocity is about 950 fps.... I have never managed to reach 50% at 950 fps, about 48% is the best I have done, even with full bore-area porting and large reservoirs....
My approach is to discourage people from wasting their time, trying to do things that are either nearly impossible to achieve, or have good, sound, scientific reasons to be counterproductive.... If they ignore my warnings, there is little downside, but for most it ends up being a learning experience....
Bob
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DonnyFL came in today, and I've got some slugs on order so I can begin shooting this rifle. I did a preliminary measurement, and the OAL will be around 43.5"
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Excited to see how this gun turns out Tom. It's been a couple years now (at least). I was thinking about making a high speed 177 shooter when you started this project. Bob I have always liked how you approach questions. I really love how you simply line out the data lol.
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Excited to see how this gun turns out Tom...
SAME!!
Okay, slight change. New estimated OAL are 39.25" w/o the LDC, and about 47" with the LDC. None of my LDC's will work w/this barrel, because the muzzle threads are a bit too long. The muzzle touches the baffles on all my LDC's save for 2, and one I'm NOT going to use on this build because I just don't think it'll work well, since it's for a .357. The LDC I'm going to use is an old NC made for a .25. SO!! There's that. No biggie at all. I'll simply use the NC, and just take it off during transport. Or leave it on. I don't know yet. The rifle case I have for LONG guns can fit 66" rifles. Doubles as a shooting mat. Should work out just fine. It'll definitely be transporting both my AF guns, as they're easily the longest guns in my collection.
NO, I couldn't wait for the dovetail to pic rail adapter to come in (for the bipod), and decided to assemble the rifle. I had to do some work on the grip, but I'll take pictures of all that tomorrow. I'm pretty happy with it! The trigger does feel good. Definitely smoother than factory. Is it BETTER? Eh. That'll be up to you. But for a drop in with nothing else done to the trigger components, it's definitely smoother. I'm really glad the Masterpiece Arms grip works comfortably with this rifle set up. The other target grip I have (LuthAR) does NOT work w/this set up.
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I forgot to mention, I picked up an Arken 4-14x scope for this build. It's still in the mail.
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Who had the you tube video a couple years ago shooting one of these guns? I think he used to be a member here on GTA.
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Who had the you tube video a couple years ago shooting one of these guns? I think he used to be a member here on GTA.
Cedric- Tofazfou. He's got 2 vids, his Gen1 build (modified Mrod) and his Gen2 build, which is an AF rifle. Other than the stock and tank, this is almost an identical copy of his build.
I'm also thinking about switching over to a CF tank... Slightly larger at 500cc, and higher fill pressure.
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Okay... She's assembled. The rifle's still not done though. Here's a quick run-down of parts again:
Condor frame
.172 Green Mountain 1-9 twist barrel, 25" long, 1" O.D. (not sure if these are still currently available though)
Doug Noble .172 top hat, valve work, and guts
WOK Guard 15
WOK-butt
Masterpiece Arms Enhanced Grip
RMP Airguns roller bearing trigger
CF 500cc 4500 psi bottle
I'm still waiting on the dovetail to picatinny conversion rail for my bipod, and I also got a conversion rail for the scope rail. I also still need to get rings- I haven't decided what I want though. Normal rings or adjustable rings... I'll figure it out. I've removed the auto-cocking dog from the gun. Anyhoo, here's a bad pic:
(https://i.imgur.com/ENHIRP9.jpg)
Darkcharisma, this pic is for you. You wanted to see how thicc the barrel is LOL It pretty much takes up the entire I.D. of the frame.
(https://i.imgur.com/fwbriw1.jpg)
Here's a shot of the WOK Guard, and the RMP Airguns trigger (well, the trigger shoe anyway):
(https://i.imgur.com/9kAQFZL.jpg)
Here's some shots of the Masterpiece Arms grip. It's kinda hard to make out, but I had to remove some material from around the back "beavertail" section of the grip, and I also installed a locating pin, just like factory AF grips have. Except my locating pin is steel. I just used a dremel to do this. Well, a dremel and a drill press. No, the grip does NOT touch the tank.
(https://i.imgur.com/2Bho4cT.jpg)
(https://i.imgur.com/tgBkFIY.jpg)
No, I'm not going to leave it that miss-match of colors, I'm going to eventually give it a coat of paint. I'm not going to do any real patterns though. Just different camo colors. Just kinda spray it around, and have fun with it.
OAL w/o an LDC is 39.5", and w/LDC is 48".
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You know the next question that will be asked....... How does it shoot!
Had to be that guy.
Your builds are always lengthy, but the end product is always worth the wait.
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You know the next question that will be asked....... How does it shoot!
Had to be that guy.
Your builds are always lengthy, but the end product is always worth the wait.
Dunno! I've got some slugs on the way.
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Nice looking gun Tom. Cedric was who I was referring to. LOL. Couldn't remember his name last night. I seen the one he had done in the marauder configuration.
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Nice looking gun Tom.
Danke!
I picked up some No Limit rings, and I'm going to put my Element Helix on this rifle- I'm going to put the Arken on the 6mm Condor.
I really want to run the DonnyFL on this rig, so I got some precision shims from McMaster Carr. .075" thick does the trick. The rest of the parts will be here around the end of the month. So I'll update again when the rest of the stuff gets here, and I can mount everything and post a "final" assembled pic for y'all. Then it's out to the field for sighting her in and getting some groups.
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Main scope rail came in today!
Still waiting on the conversion rail for the bipod
Still waiting on the no-limit rings
Slugs came in today as well- they look fantastic! I got some cast (solid- not HP), along with some swaged (HP). I can't wait until everything is together, so I can do some shooting!!
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FX No Limits rings came in today!
Still waiting on conversion rail for the bipod...
Here's a shot w/the scope on (Element Helix):
(https://i.imgur.com/96Tsom0.jpg)
DonnyFL LDC:
(https://i.imgur.com/nUGe2Ba.jpg)
Scope mounted. I'm glad I got this conversion rail! I would have had to figure out another solution to mount the scope if I hadn't... I know it looks silly, but that's where it needs to be for me...
(https://i.imgur.com/gJkF1qJ.jpg)
Comparison between the factory (R) trigger and the RMP Airguns trigger (L). Not of my specific trigger, this is Tofazfou's trigger. But it's the exact same as mine, aside from the color. Ced went a step further and added a trigger spring(s) from Talon Tunes. I have not (probably won't).
(https://i.imgur.com/YD1A6ws.jpg)
Now all that's left is to get the bipod on there...
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The ergonomics on that upgraded trigger look good. Amazing how something so trivial can make such a huge difference.
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I ordered a Tatsu to replace the "FX" LDC for this build. Much more fitting size, and I don't need a spacer for it. I can use the "FX" ldc for one of my other builds.