Barrel en twist for a 22 LR
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There are a few twist for .22lr. They range from 16- 19. Some of the Suhl's came with a 19 twist. They shoot good in wind. The more wind the higher twist. I myself shoot .22lr benchrest. I have found that Benchmark barrels work the best for me. I have a Hall with a 17 3/4 twist and a 40X with a 16 1/2 twist. Both built by Gene Davis out of Ohio.
I think 1 in 16 was the only choice for many years, and still is in my opinion for most applications. Remington made their 40x benchrest rifle,with the green stock) with a 1 in 14 twist for a while. It had a reputation for great accuracy in calm conditions but a real bear in any wind at all. The slower twist barrels are supposed to drift less in the wind with standard velocity target ammo. In ARA the 1 in 17 is very popular. Some Suhl's had 1 in 19 and I think a few custom makers will make that twist also. As I understand it the slower twist stabilizes in warmer temperatures but you risk keyholing in colder weather. So like many things, there is no perfect twist for all situations. I have 17's on my bench rifles and 16's on everything else. I don't think I personally would risk the money on a 1 in 19 that may be excellent or a dog. Rich
I have two Suhls and both have 1:19 twist barrels. They shoot GREAT at shorter distances, but SUCK at distance. Both will shoot under .25" at 50 yards with the right ammo, but one will not shoot much past there. Neither will shoot well at 200 yards.
I would suggest a twist rate at least as fast as 1:17 and preferrably 1:16 for general purposes, the 1:17 being more popular with the 50 to 100 yard shooters.
I would suggest a twist rate at least as fast as 1:17 and preferrably 1:16 for general purposes, the 1:17 being more popular with the 50 to 100 yard shooters.
Thompson Center, whether "production" or Custom Shop, make their .22 LR at 1:15. My TC 1:15 match chambered .22 LR shoots like an Anschutz.
Also, almost all commercial brands use the "standard" 1:16 for .22 WMR as well. Probably just re-chamber the standard .22 LR barrel. But, the TC Custom Shop uses 1:12 for .22 WMR, which I prefer. Better for the HV or heavier than 40gr ammo.
Also, almost all commercial brands use the "standard" 1:16 for .22 WMR as well. Probably just re-chamber the standard .22 LR barrel. But, the TC Custom Shop uses 1:12 for .22 WMR, which I prefer. Better for the HV or heavier than 40gr ammo.
Not being an expert on ballistics, my comments are more question than fact. But the amount of spin on a bullet providing stability as we all know is a function of the speed and bullet weight among other things. Regarding the .22 rimfire, and what little I know about centerfire, the 40 gr bullet needs more spin the slower it goes. So a slow twist, 18 or 19 might be better for 50 yd benchrest but fall on its face at 100 yds because velocity is not fast enough to maintain stability at 100 yards. A short barrel handgun with lower velocity might need a faster twist to maintain stability. Even though HV ammo is not normally as accurate as standard velocity, it might give better accuracy at longer ranges in some guns. Does this make sense or am I blowing hot air again.
Rich
RichRich,
What you said makes perfect sense to me…at least intuitively. But, it would probably take a “lot†of testing with many different firearms to verify the perfect twist and velocity for various yardages.
The only point you mentioned I might take exception to is the weight of the bullet being a factor for stability, but with rimfire bullet shapes being almost identical…any increase in weight in most cases would increase the length and length is the primary factor for calculating projectile stability. So, in other words, I agree.
We can calculate stability by using this formula: Where Sg = Bullet stability Sg=,30*C5)/,,C7/C4)^2*C4^3*C6/C4*,1+,C6/C4)^2))*,C8/2800)^,1/3)*,,C9+460)/,59+460)*29.92/C10)
This formula was devised by Don Miller and is even endorsed by Bryan Litz as being very accurate, but when dealing with rimfires operating in the Mach 1 envelope…results can often be skewed by the smallest of variables. These variables would include the susceptibility of soft lead projectiles being deformed by the bore to a different shape and length. Something you normally wouldn’t have to account for in a jacketed bullet operating at supersonic velocities.
With these caveats predisposing truly accurate results, we can still estimate stability as an exercise in curiosity if you can give me an average for the length of the heel on a 22lr bullet. I didn’t want to pull any and can’t remember off the top of my head how far the heel of the bullet protrudes into the case.
I haven’t done this yet and I’m not aware of anyone else trying it on the many forums I lurk at. Your post has made me curious and it will only take me a few minutes to do some calculations with this formula because its embedded in a cell on an Excel spreadsheet and I can easily plug in the variables for twist, length, velocity, caliber, temperature, and pressure.
What you said makes perfect sense to me…at least intuitively. But, it would probably take a “lot†of testing with many different firearms to verify the perfect twist and velocity for various yardages.
The only point you mentioned I might take exception to is the weight of the bullet being a factor for stability, but with rimfire bullet shapes being almost identical…any increase in weight in most cases would increase the length and length is the primary factor for calculating projectile stability. So, in other words, I agree.
We can calculate stability by using this formula: Where Sg = Bullet stability Sg=,30*C5)/,,C7/C4)^2*C4^3*C6/C4*,1+,C6/C4)^2))*,C8/2800)^,1/3)*,,C9+460)/,59+460)*29.92/C10)
This formula was devised by Don Miller and is even endorsed by Bryan Litz as being very accurate, but when dealing with rimfires operating in the Mach 1 envelope…results can often be skewed by the smallest of variables. These variables would include the susceptibility of soft lead projectiles being deformed by the bore to a different shape and length. Something you normally wouldn’t have to account for in a jacketed bullet operating at supersonic velocities.
With these caveats predisposing truly accurate results, we can still estimate stability as an exercise in curiosity if you can give me an average for the length of the heel on a 22lr bullet. I didn’t want to pull any and can’t remember off the top of my head how far the heel of the bullet protrudes into the case.
I haven’t done this yet and I’m not aware of anyone else trying it on the many forums I lurk at. Your post has made me curious and it will only take me a few minutes to do some calculations with this formula because its embedded in a cell on an Excel spreadsheet and I can easily plug in the variables for twist, length, velocity, caliber, temperature, and pressure.
Clark,
Can you measure the length of those two bullets with a set of calipers and provide them so we can see how accurate the formula might be. Just curious.
Can you measure the length of those two bullets with a set of calipers and provide them so we can see how accurate the formula might be. Just curious.
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