Severe under stabilization would show keyholes. Very minor under stabilization just might show up as bad grouping.
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Do you expect your Pellet gun to shoot Slugs?
- Thread starter Centercut
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Quite true, it "just might". IMO, the problem with your point of view is that the "very minor understabilization" would be creating YAW when it starts and it sure seems logical that such YAW, once it started, would rapidly destabilize the projectile further. If such is a concern and one believes it is happening at a given range and "just might" be the reason for poor accuracy, why not just shoot at a bit longer range and SEE whether the change (keyholing) is beginning?
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Yep yep. Also one big problem with pellet gun vs slug gun is infact wrong twist. Even slowest twist possible to stabilize anything thats not drag stabilized is too fast for dragstabilized pellets if we speak about optimal performance. Therefore good pelletgun never makes good slug gun and otherway around. Choke and no choke has nothing to do with anything. Generally choke is just bad try to improve bad barrel nothing else. If your barrel is good it dosent need choke even if you only shoot pellets.
Before someone jumps in and tells their this and that shoots both well yep sure it dose. Just specific twist for certain type projectile dose it even better.
Before someone jumps in and tells their this and that shoots both well yep sure it dose. Just specific twist for certain type projectile dose it even better.
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Severe keyholes might not show up at the realistic airgun ranges that most of us shoot. When I experience poor accuracy once I reach 100yrds I am either done with that tune, projectile, or both. What you are talking about might not become obvious until 150+. I just never tried.
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Good enough, and POSSIBLY correct. But again, a "might not". And why is "severe" stated? Wouldn't just some keyholing beginning to be observed be significant? Such a discussion just seems to make it extremely hard to identify EXACTLY what is causing the problem mentioned (any noted loss of accuracy) instead of speculating on what the cause might be. So, instead of increasing the distance, how about raising velocity to increase spin rate and compare THAT WAY?
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The whole twist versus speed thing just doesn’t sit well with me and here’s why. My accurate consistent slug guns shoot great from 750fps to 950fps. With the right combo, I never had to speed a slug up to get it to shoot well. There is more to slug accuracy when pushed by air than just twist rate alone. That’s what makes is more difficult and why there are a lot of hits and misses. Just when you think you have a solid theory and are ready to live by it, along comes another barrel/slug combo that proves you wrong. Slug manufacturers sit back and love it. $$$$$$$$!!
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"along comes another barrel/slug combo that proves you wrong". OR barrel/pellet combo as well. But I agree entirely, and that has been my point. How does one identify any consistent trait that is causing the "accuracy issue" if slight changes in those traits change results completely?
jikuu-
"Therefore good pelletgun never makes good slug gun and otherway around". THERE is a very loudly stated opinion-"never". I dismiss this opinion out of hand, primarily because of the never, but that's just my equally loudly stated opinion.
jikuu-
"Therefore good pelletgun never makes good slug gun and otherway around". THERE is a very loudly stated opinion-"never". I dismiss this opinion out of hand, primarily because of the never, but that's just my equally loudly stated opinion.
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Yes never might be wrong term but point being optimal twist for pellet isnt optimal for slug and other way around and optimal dose mean better. 22cal with 1:16 for example is optimal for slugs at 40grainish but you get better performance 100% with pellets by choosing something much slower. You can get away with pellets also with that twist but then you are limited to certain speed while you could shoot them harder with slower twist. Rti prophet high speed LR model for pellets with 1:32tr is just big statement towards this. It shoots pellets accurate no matter how fast you shoot them.
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I have discovered one trait that seems to be very consistent. Blow by. Pellet guns have pellet leades or chambers. They get lots of blow by when the air meets the base of the slug. Some manufacturers have a better or shall we say a more versatile leade and now slugs start showing promise in these guns. FX possibly by luck stumbled onto alleviating this problem with their original smooth twist and now to this day their very shallow rifling. When you seat a slug into standard rifling, unless your slug and leade equal a nice seal, you’re going to have blow by. With a firearm this is not a problem when the fire meets the lead bullet. It’s an instant seal at those pressures. Sometimes it can even be extreme and that’s when gas checks are utilized.
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Agree totally. Other than the "lead "part as most are copper on the outside but your point is taken-plenty of "excess" energy to seal the bullet in the bore. I posted about this exact thing quite a while back regarding the very short NSA 12.5 grain .177 slugs. I believe it was Motorhead (not certain who it was at this moment) who was trying some 12.5 NSA slugs and getting some odd fliers. I was seeing the same thing with my .177 Condor-some pretty impressive tight groups spoiled by the odd flier. In my Condor, those slugs wouldn't engage the leade well enough to stay in place with just thumb pressure-hold the gun muzzle up and the slug would fall back out, My thought was that either blow-by or misalignment was happening with those short slugs. I eliminated ALMOST all of that by making an indexed adjustable depth seating tool. Still would see an occasional shot a bit off an expected good group but MUCH fewer in number and MUCH less distance from POA when it did happen. WAS IT BLOW-BY OR MISALIGNMENT OF THE VERY SHORT SLUG? No way to tell FOR CERTAIN as far as I can see. But the problem went from very noticeable to inconsequential for my shooting once I started seating the slugs well into the rifling.
l.
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I have no expectations for my pellet guns to shoot slugs, but I there are some brands with certain brands and types of barrels that are predisposed to shoot slugs better than others. And there are the surprises that pop up too.
For an airgun like the Cricket with an exposed rotary mag with orings that are meant to grip the thinner waist of the pellet between the head and skirt and keep it in place - slugs are not really ideal. They just fit the mags well and keeping them in place on a bench is one thing, but they'd fall all over the place if brought into the field.
So not only do twist, choke, speed, etc have to in alignment - it's gotta have a slug friendly magazine.
I've been trying to learn more about internal ballistics and my understanding is twist rate has a relation with projectile length. My example is a YT video I watched recently on 30-06 cartridge. The guy was talking about a 1 in 10 twist being the standard and being able to support from 40 up to about 200 grain bullets. He said the projectile in that barrel gets a bit wobbly when you try to send 220+ grain projectiles. You'd need a slightly faster twist to support the heavier bullet. I don't fully yet the relationship between heavier projectile, shorter or longer and twist rate.
What I got from the YT video is that our pellet barrels usually have too slow a twist rate for heavier slugs. Or is it too fast? I get myself confused here still. But this leads me to agree with what Vetmx said. You don't have to push slugs to 950 - 1050 fps to get them to shoot well - and depending on the twist of the barrel they may shoot better slowly. I find this to be 100% true in my .22 LW Leshiy 2 barrel. Slugs suck up around 900 fps, but if I keep them around 825 fps I can pull 1/2" groups easily with the NSA .22 20.2 and 23 grain slugs.
The other Leshiy 2 barrel I have, a 450 mm .25 Alfa barrel, was said to be more slug friendly and it does best with 30-40gr slugs up in the 940-950 fps range. Down in the 800s the .25 slugs do not group at all.
I don't have a preference - I just want the best shooting projectile for the gun.
For an airgun like the Cricket with an exposed rotary mag with orings that are meant to grip the thinner waist of the pellet between the head and skirt and keep it in place - slugs are not really ideal. They just fit the mags well and keeping them in place on a bench is one thing, but they'd fall all over the place if brought into the field.
So not only do twist, choke, speed, etc have to in alignment - it's gotta have a slug friendly magazine.
I've been trying to learn more about internal ballistics and my understanding is twist rate has a relation with projectile length. My example is a YT video I watched recently on 30-06 cartridge. The guy was talking about a 1 in 10 twist being the standard and being able to support from 40 up to about 200 grain bullets. He said the projectile in that barrel gets a bit wobbly when you try to send 220+ grain projectiles. You'd need a slightly faster twist to support the heavier bullet. I don't fully yet the relationship between heavier projectile, shorter or longer and twist rate.
What I got from the YT video is that our pellet barrels usually have too slow a twist rate for heavier slugs. Or is it too fast? I get myself confused here still. But this leads me to agree with what Vetmx said. You don't have to push slugs to 950 - 1050 fps to get them to shoot well - and depending on the twist of the barrel they may shoot better slowly. I find this to be 100% true in my .22 LW Leshiy 2 barrel. Slugs suck up around 900 fps, but if I keep them around 825 fps I can pull 1/2" groups easily with the NSA .22 20.2 and 23 grain slugs.
The other Leshiy 2 barrel I have, a 450 mm .25 Alfa barrel, was said to be more slug friendly and it does best with 30-40gr slugs up in the 940-950 fps range. Down in the 800s the .25 slugs do not group at all.
I don't have a preference - I just want the best shooting projectile for the gun.
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I was referring to firearms that shoot lead bullets. But trust me, the ones that shoot copper bullets have a very tight fit. That’s why they have to jump into the rifling or you’ll have an accident. 50,000cup is nothing to mess with.
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Well laid out. My Pulsar magazine feeds slugs perfectly, and it shoots BOTH pellets and slugs very accurately. My 2 rifles with the o-ring retention method in the mags (HW100 and Hatsan Gladius) have both jammed with slugs. Both shot the slugs well enough, but feeding them was not reliable because there is no "waist" for the o-ring to engage and the slugs shift front to rear in the magazine.
Air gun twist rates are commonly viewed as "too slow" for longer slugs. 1:17 or 1:16 (common in many air guns) is "slower" than 1:12 or 1:10. My understanding is that faster twist is needed both for longer and heavier projectiles, though not in a direct 1:1 relationship. Seems to be most critical for longer vs. heavier but I'm not certain where/how the distinction would be seen.
Velocity is also related, as higher velocity results in higher spin of the projectile for a given twist rate of the barrel. That is why I mentioned "speeding up" in some above discussions. Not that the speed is "needed" but that the speed creates higher spin rate which MIGHT add stability for a bit further distance. I would say that just as the 30-06 example mentions, a point will be reached with decreasing velocity where the given twist WILL NOT produce enough "spin" to stabilize a longer/heavier projectile. BUT if a given slug is stable in a given barrel, WHY NOT use more speed to gain flatter trajectory IF ACCURACY IS NOT REDUCED due to encroaching on that magical trans-sonic zone? Seems given those conditions (the if and WHY NOT), only a decrease in shot count could be viewed as a possible negative to the added speed.
Too fast can be bad (for several reasons). Too slow can be bad (also for several reasons). Seems that the "all relative" thing has reared it's head again.
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I think you nailed it there. And because we can adjust velocity so easily on airguns, the tuning for a slug in the right barrel should be easier.
The take away seems to be really to try all velocities in any given setup before ruling out a slug.
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Twist required is due speed, twistrate lenght of the projectile and weight but most importantly shape. I have 224cal airgun with 12,6" twist that can stabilize certain type fn fb 60+gr bullets but is on the edge of stability with 51gr spitzers. Thats why you use stability calculators to ease out matching your projectile with your twistrate and most importantly size your barrel and size your projectiles to proper size. Also twist required is completely different on subsonic speeds versus supersonic speeds and you need faster twist to shoot certain weight projectiles at subsonic speeds like a lot faster than you need if you shoot them 3000fps. But to put it on simple perspective way if you shoot pellets take slowest you can find if you shoot slugs and cant find perfect fit for a twist required choose something bit faster but never take anything slower.
Also no matter what you do atleast firelap your barrel if you dont buy premium match grade handlapped barrels it will save alot of time and money and extend your cleaning free periods alot since slugs tend to lead your barrel alot more.
And as said above ideally for proper slug build you choose projectile with matching barrel and have custom chamber and throat cut for it. Ideally same apply as on firearms properly cut chamber you have your chosen projectile softly sitting on your throat and no excess woble or room around or backwards. Crowning of your barrel is also really important and longer projectiles you shoot more important it gets. Badly cut crown easily makes longer bullets wobble when exiting barrel and please doing it with dremel isnt really the proper way just spend that few bucks to have gunsmith doing it.
Now to take all these said into consideration I do not expect any pellet airgun to shoot slugs well but since there is plenty of manufacturers jsb, nsa, hn etc designing pellet rifle intended slugs to shoot well out from standard pellet airguns some of them do shoot them well and it save alot of time and effort since im fairly sure 99% of airgunners dont give s flying fu*k about stuff some of us are doing in order to chase longer, faster, higher bc guns.
Also no matter what you do atleast firelap your barrel if you dont buy premium match grade handlapped barrels it will save alot of time and money and extend your cleaning free periods alot since slugs tend to lead your barrel alot more.
And as said above ideally for proper slug build you choose projectile with matching barrel and have custom chamber and throat cut for it. Ideally same apply as on firearms properly cut chamber you have your chosen projectile softly sitting on your throat and no excess woble or room around or backwards. Crowning of your barrel is also really important and longer projectiles you shoot more important it gets. Badly cut crown easily makes longer bullets wobble when exiting barrel and please doing it with dremel isnt really the proper way just spend that few bucks to have gunsmith doing it.
Now to take all these said into consideration I do not expect any pellet airgun to shoot slugs well but since there is plenty of manufacturers jsb, nsa, hn etc designing pellet rifle intended slugs to shoot well out from standard pellet airguns some of them do shoot them well and it save alot of time and effort since im fairly sure 99% of airgunners dont give s flying fu*k about stuff some of us are doing in order to chase longer, faster, higher bc guns.
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I agree. THAT is why I don't put the "trans-sonic" zone at the TOP of my considerations. Too arbitrary, too theoretical. It seems that MANY slugs, as well as lots of pellets (read Tom Gaylord's testing of such from long ago), have been shot in that "speed range" and NOT lost accuracy. But IF ACCURACY IS IMPACTED AT SOME SPECIFIC HIGHER VELOCITY, then just slow it down IF THAT IS NECESSARY until the accuracy returns. Or speed it up if you can, although air gun power levels makes that adding of velocity much harder to realize a gain from. Something I like to say surely fits here-all relative.
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"im fairly sure 99% of airgunners dont give s flying fu*k about stuff some of us are doing in order to chase longer, faster, higher bc guns."
I'll agree with THAT 1000%.
I'll agree with THAT 1000%.
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I have an impact mk2 25cal 700mm slug liner A and I have installed a pp and slug power kit! With excellent results with nsa slugs 250 and I have chosen to stick with the 36.2 slugs. With that being said I have had an interest with the 177 nsa slugs so I have purchased a pulsar 177 and have not been let down. My results with the nsa 178 slugs both the 12.5&15 are impressive. I only hope that I have answered the original question!? Always interested in sharing my thoughts and experience. My personal expectations have been met . Nice post
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Look who started the topic. That’s why the topic is rolling along the way it is. My teachers always said there are no dumb questions. But some questions are better than others. Especially if it hasn’t been beaten to death. This topic can possibly save many repetitive questions from newbies if they aren’t too lazy to search.
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