34gr Bullets in AR?
- Thread starter bluetopper
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velvethunter
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- Jan 1, 2012
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You can defnitely under stabilize a bullet and have it keyhole, that pretty common. Over stabilizing seems less problematic overall. It may not be the most accurate to shoot out of your particulart rifle, but unless is a super thin jacket and you spin the bullet apart it will either shoot decent or it won't. Personally, I have shot the 36 gr VG's out of an 8 twist, and while not quite as accurate as a 69gr matchking(this rifle's favorite), they were more than adequate, averaging around .75 moa.
gdcpony
Member
I did an experiment with 40gr pills out of my 1/9 AR. Worked great. Can't say my results were standard, but they hit in nice tiny groups and didn't fly apart.
Here:
http://www.thehighroad.org/showthread.php?t=507874
The pics are gone by now, but the numbers are there. I can post pics up if you would like.
I later found I was getting 3400 out of the tiny pills. I went to a 50gr load and am getting 3200 out of those. My daughter's 22" bolt gun with the same twist gets 3700 and 3400 respectively.
Here:
http://www.thehighroad.org/showthread.php?t=507874
The pics are gone by now, but the numbers are there. I can post pics up if you would like.
I later found I was getting 3400 out of the tiny pills. I went to a 50gr load and am getting 3200 out of those. My daughter's 22" bolt gun with the same twist gets 3700 and 3400 respectively.
2ndtimer
Member
Which would not explain why the same loads stabilized and reached the target in 2 other slower twisted rifles.
J_McLeod
Member
Interesting thread. I found it while considering buying some of Midsouth's 34gr Varmint Nightmares. I'd be loading them in my 1:8" 16" barrel AR for non bench/competition shooting at less than 100 yards. Still not sure about it.
Tim, unless the laws of physics has changed and the world is actually flat (just don't fall off the edge). Weight and length are joined at the hip and are related. A 223 bullet is .224 in diamiter and that does not change the only way the weight can change is by being longer or shorter. The longish bullets you used in your 1:8 twist rifle must have been .222 bullets for the 221 Fireball or 222 Remington or 220 Swift. Not ment for a 223/5.56 AR.
Jim
Tim the student
Member
wgaynor
Member
How about the Mods move this to the handloading section and see what info comes to light?
Or changing shape or construction. When I've got 3 bullets of .224 caliber all weighing 50gn and all three are vastly different in length and have heavier bullets that are shorter than lighter ones, your gross generalization doesn't hold up. A flat based bullet will weight more than a boattail of the same length with the same ogive shape. A semi-spitzer will weigh more than a true spitzer and certainly more than a poly tipped bullet of the same length and a round nose is the heaviest shape per length of all. And then there's bullet construction. Changing the composition of a bullet has dramatic changes in the bullet length to weight ratio. Adding a steel penetrator as in the M855 will increase length for a given weight, likewise going with a polymer tip. Solid copper or gilding metal bullets are very long for their weight as are the frangible designs that use a powdered copper-tin core instead of lead. On the other end of the spectrum are the powdered tungsten core bullets like those from DRT and Hevi-shot which are very short considering their weight.
OP
OP
bluetopper
Member
The 34gr Varmint Nightmare bullets sold by Midsouth are the bullets I was asking about. They shoot like a laser out of my 1:12 twist, 14" Thompson Contender barrel. I can lay a quarter over the 100yd groupings. I suspect these bullets were really made for the 22 Hornet, 221 Fireball, 222 and the like, but don't really know this as fact.
I've just never got around to testing any in my M4 Carbine, 16" barrel. I think it has a 1:8 twist.
Another subject all together.....but what astonished me shooting my Contender is the difference in flash and boom different powders made out of it's shorter barrel. Shooting H335 was like shooting a cannon, yet H322 and 748 had half or less of the report.
I've just never got around to testing any in my M4 Carbine, 16" barrel. I think it has a 1:8 twist.
Another subject all together.....but what astonished me shooting my Contender is the difference in flash and boom different powders made out of it's shorter barrel. Shooting H335 was like shooting a cannon, yet H322 and 748 had half or less of the report.
The comment made was that there is no relationship between length and weight of the same caliber bullets of the same materials, that is just not true. Yes you can make a bullet out of different materials but that is like comparing apples and oranges, not the same thing.
If you have to use a lead free bullet, yes it will be longer for the same weight bullet out of lead. But a 50 grain lead free bullet IS shorter than a 55 grain lead free bullet.
Jim
If you have to use a lead free bullet, yes it will be longer for the same weight bullet out of lead. But a 50 grain lead free bullet IS shorter than a 55 grain lead free bullet.
Jim
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What? My three 221 Remington Fireball firearms use .224" diameter bullets.
All the reloading manuals I have dating back to 1980 use .224" diameter bullets in 221 Remington Fireball, 222 Remington, and 220 Swift.
I guess i missed something somewhere.
Helotaxi covered the weight/length thing pretty well.
To add an example, I am working on getting 40 grain 20 caliber bullets to shoot in my Savage 12. The twist rate is marginal for the length of 40 grain bullets
The Hornady VMAX, Sierra Blitzking, and Berger HP all weigh 40 grains, all are lead core, copper jacket construction, and all are different lengths. The lengths are enough different that you can see it with the naked eye, no caliper needed.
That's why I really like my 1:9 twist .204. Shoots 26gn Varmint Grenades up to the 55gn VLDs (at least at this elevation) without a problem. I'd actually like a 1:8 but can't find anyone that makes one.
Once again you're making an assumption that simply isn't true. You're completely neglecting bullet shape.
Three .224 cal poly tipped varmint bullets that I have in my cabinet. Which is the heaviest? Which is the lightest?
Look a the datasheet that Berger publishes for their bullets. There are numerous examples there of lighter bullets being heavier than lighter ones and two bullets of the same weight being different lengths.
Differences in pressure curve. The same thing is pretty common from handguns as well. Slower powders will have more residual pressure when the bullet leaves the muzzle. Has nothing to do with how much powder has burned.
Wearing my junior physicist hat, there is a point being missed here with the statement, 'you can't overspin a bullet'. In fact and within reason, I believe this is true (the caveat being that successfully and sufficiently over-spinning a bullet will amplify any non-uniform weight imperfections and ultimately impart a distorted spin).
But short of that, the real issue is not in over-spinning but failing to overspin, or adequately spin. That is, for a given barrel length, there is a narrow window of bullet mass and barrel spin coefficient (1:7 or 1:12 or somewhere in between). Given a sufficiently heavy bullet, the lower ratio's (say 1:7) will fail to overcome the mass of the bullet and, at the time of exiting the barrel, simply fail to radially accelerate the mass of the bullet. This failure results in too low a spin rate and a poor stability. On the other end, if you spin a low mass bullet too slowly (say a 35 grain bullet with a 1:12 barrel), it too may have too low a spin rate and fail.
So it's not (within limits) over-spinning that is the problem, but a failure to reach an adequate spin rate with heavy bullets and low-ratio barrels that is an issue.
BTW, when shooting too heavy a bullet in too 'fast' a barrel, I suspect that there will be a more rapid buildup of bullet-material residue in the barrel as well.
Comments welcomed.
V
But short of that, the real issue is not in over-spinning but failing to overspin, or adequately spin. That is, for a given barrel length, there is a narrow window of bullet mass and barrel spin coefficient (1:7 or 1:12 or somewhere in between). Given a sufficiently heavy bullet, the lower ratio's (say 1:7) will fail to overcome the mass of the bullet and, at the time of exiting the barrel, simply fail to radially accelerate the mass of the bullet. This failure results in too low a spin rate and a poor stability. On the other end, if you spin a low mass bullet too slowly (say a 35 grain bullet with a 1:12 barrel), it too may have too low a spin rate and fail.
So it's not (within limits) over-spinning that is the problem, but a failure to reach an adequate spin rate with heavy bullets and low-ratio barrels that is an issue.
BTW, when shooting too heavy a bullet in too 'fast' a barrel, I suspect that there will be a more rapid buildup of bullet-material residue in the barrel as well.
Comments welcomed.
V
It is amazing how you all can go on and on and not answer the questioned asked by the individual asking it. All he wanted to know is will a 34gr cycle in an AR rifle.
Yes it will if the powder charge is enough as it is with 55gr or longer bullets.
Yes it will if the powder charge is enough as it is with 55gr or longer bullets.
Huh?
The only way that a barrel fails to impart spin on a bullet (assuming that the barrel and bullet are correctly matched in bore/caliber) is if the rifling sheers the outer surface off the jacket. This jacket damage does occur and is sometimes the culprit with light bullets behaving erratically in a fast twist barrel. The bullet slams into the rifling with enough velocity that its angular inertia overcomes the integrity of the jacket. With a heavier bullet, the slower acceleration of the bullet makes it much less likely. Different types of rifling make this more or less likely to occur.
The only way that a barrel fails to impart spin on a bullet (assuming that the barrel and bullet are correctly matched in bore/caliber) is if the rifling sheers the outer surface off the jacket. This jacket damage does occur and is sometimes the culprit with light bullets behaving erratically in a fast twist barrel. The bullet slams into the rifling with enough velocity that its angular inertia overcomes the integrity of the jacket. With a heavier bullet, the slower acceleration of the bullet makes it much less likely. Different types of rifling make this more or less likely to occur.
stubbicatt
Member
This does not comport with my observation of 45 grain Winchester factory ammo out of a SIG556 w/ a 7 twist.
They shot great!
However, in a Krieger 7.7 twist the 52 grain bullets would blow up occasionally on their way to the target... I could see a "puff of smoke" downrange where the bullets (Sierras) would spin themselves into disintegration.
I cannot necessarily explain it, but I have seen it.
I guess to OP, try it and see. If it doesn't work, you are only out a few dollars.
TurboFC3S
Member
Just a data point, not meant to prove or disprove anything ... but
I pushed 40gr out of a 1:9 twist 223WSSM 24" barrel to 4550 fps and got sub 1/2" 5 shot groups. Basically that was an experiment when I got my Chrono to see how big a number I could put up
I have no idea what sort of terminal ballistics something like that would have, but I imagine it would be akin to having a small grenade go off 3" under your skin.
I pushed 40gr out of a 1:9 twist 223WSSM 24" barrel to 4550 fps and got sub 1/2" 5 shot groups. Basically that was an experiment when I got my Chrono to see how big a number I could put up
I have no idea what sort of terminal ballistics something like that would have, but I imagine it would be akin to having a small grenade go off 3" under your skin.Yeah, don't mind him. He's still stuck in some Twilight Zone where modern understanding of what's going on with a bullet in flight hasn't come to light yet or modern bullets aren't available.
Yeah it happens. Some bullets are notorious for it. Most of the newer varmint bullets are designed to be driven *really* hard though. Mach snot is the term I like. They hold up fine with high velocities and fast twists...until they hit something.
Sounds "sporty". If they're anything like the 58gn VMax and 55gn BTs that I've shot from a .243 at over 4kfps, "spectacular" is a great description of the terminal effects. Shooting gourds out to 300+ yds sounded like slapping a wet towel on a wall and completely disintegrated the 2.5-3" gourds.I pushed 40gr out of a 1:9 twist 223WSSM 24" barrel to 4550 fps and got sub 1/2" 5 shot groups. Basically that was an experiment when I got my Chrono to see how big a number I could put up
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