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TED
08-05-21, 02:36
I am somewhat familiar with the various common twist rates available for 5.56 and the history and impact (or not) on terminal effect. However I lost a piece of information...

I once found an article that included a chart saying that 1/11 was better for stabilization o0f the 55gr m193 load but that the military decided screw 1/12 is close enough.

Assuming that I only ever shoot 55gr and that I am ok with using M193 for defense, I have considered looking for a 1/11 twist barrel. I have not found any.

Does anyone know of some place that makes 1/11 twist barrels?

Thanks.

TED
T2C
08-05-21, 05:43
Many years ago Armalite built rifles with 1:11 twist barrels.
mig1nc
08-05-21, 06:43
The Brownells retro barrels are 1:12


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davidjinks
08-05-21, 09:45
Bartlein barrels lists 1:6.5 through 1:14 twist rate for .223/5.56.

That’s the only manufacturer I found who offers a 1:11. Possibly kreiger would make a custom barrel? But I’ve never dealt with them before.

EDITED TO ADD: https://bartleinbarrels.com/calibers/


I am somewhat familiar with the various common twist rates available for 5.56 and the history and impact (or not) on terminal effect. However I lost a piece of information...

I once found an article that included a chart saying that 1/11 was better for stabilization o0f the 55gr m193 load but that the military decided screw 1/12 is close enough.

Assuming that I only ever shoot 55gr and that I am ok with using M193 for defense, I have considered looking for a 1/11 twist barrel. I have not found any.

Does anyone know of some place that makes 1/11 twist barrels?

Thanks.

TED
Red*Lion
08-05-21, 12:17
Why bother looking for a barrel with a 1/11 twist when whatever you find will either be over-priced or poor quality. Most 1/7, 1/8 and 1/9 barrels will shoot 55 grn just fine.
Tony617
08-05-21, 13:00
Why bother looking for a barrel with a 1/11 twist when whatever you find will either be over-priced or poor quality. Most 1/7, 1/8 and 1/9 barrels will shoot 55 grn just fine.

I bought a Armalite M15 years ago with a 1/9” twist with 16” barrel and will shoot .223 or 5.56mm rounds just fine. I have shot 55gr .223, 50gr TSX from Black Hills, 55gr, 62gr 5.56mm rounds. For 55gr 5.56 rounds, I have fired X-TAC, LC, or IMI rounds. For 62gr LAP, I have fired LC, X-TAC, and IMI rounds.

For for the 69gr or 77gr 5.56 rounds I only shoot those from a 1/7 twist barrel.
markm
08-05-21, 14:49
Why bother looking for a barrel with a 1/11 twist when whatever you find will either be over-priced or poor quality. Most 1/7, 1/8 and 1/9 barrels will shoot 55 grn just fine.

Absolutely. No sense in finding an optimal twist just to shoot sub-optimal ammo/bullets.
T2C
08-05-21, 20:00
Why bother looking for a barrel with a 1/11 twist when whatever you find will either be over-priced or poor quality. Most 1/7, 1/8 and 1/9 barrels will shoot 55 grn just fine.

The Armalite rifle I shot years ago had a 1:11 twist stainless steel barrel and it exhibited decent accuracy out to 400 yards with M193 ball. It easily outshot my Colt HBAR with 1:7 twist barrel by a wide margin.

Don't expect a 1:11 twist barrel to shoot well with heavier projectiles.
jbdesigns
08-05-21, 20:25
I have felt that if one were to use only 55gr FMJ for self defense, then a 16” to 20” barrel with 1:12 twist would be optimum to get terminal effects from the bullet. Tumble is more assured on impact.


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Todd.K
08-05-21, 23:15
I have felt that if one were to use only 55gr FMJ for self defense, then a 16” to 20” barrel with 1:12 twist would be optimum to get terminal effects from the bullet. Tumble is more assured on impact.

No.

It would take an astronomical amount of twist to keep a bullet stable through flesh.

Observations of good and poor terminal performance were both found to be true. High speed cameras show it was caused by “Fleet yaw” and the slight difference of angle the bullets were hitting the target at out of individual barrels, not barrel twist rate.
Stickman
08-07-21, 16:15
Original green model 601s were 1/14….
TexHill
08-07-21, 17:29
Original green model 601s were 1/14….

Correct, and the twist rate was changed from 1/14 after there were issues during arctic trials.
Disciple
08-07-21, 20:17
Observations of good and poor terminal performance were both found to be true. High speed cameras show it was caused by “Fleet yaw” and the slight difference of angle the bullets were hitting the target at out of individual barrels, not barrel twist rate.

What factors produce or contribute to fleet yaw?