Twist rate in .223 AK

[RPK]

I have heard various things about there needing to be a certain rifling twist rate in the AR-15 series for proper bullet stability in flight.
Is this the case with the AKs in .223?
Are different countries manufacturing theirs with different twist rates?
How does this affect the accuracy?

[hcore]

Im am pretty sure that the SAR3 has a 1 in 8.5 twist. FWIW

I have not been able to see much difference with the accuracy in either the 55 or 62 gr. ammos that I have tried but I have not used the penetrator 62 grs that the military does. Just Federal american eagle and russian 62gs. I don't think that either of them are significantly longer than the 55gr to make a difference. both group well at 50yds but not so good out to 100 but that might be me not the load.

[Ratlord]

This is the case with all rifles, I beleive. The twist rate would determine your most accurate bullet weight. You may notice that some rifles are extremely accurate with one bullet weight but inaccurate with another bullet weight. This is not typically the kind of stuff you find in the manual, though :P

[Archivist Dick]

RPK, handloading the 223Rem/5.56mmNATO is easy peezy, cheap, and profitable from the accuracy standpoint.

Experiment.

Shoot more.

Once you've developed an optimum load, crank out a boatload of handloads and get down to it.

[WildWes]

Rate of twist in Norinco 5.56 rifles is 1 in 9. My most accurate results have been with 55 grain loads.

[ppro]

I wouldn't be to worried about twist per say. Generally, the lighter bullets shoot fine in the 8 and 9 twist guns and I have had 52's shoot well in 7 twist guns. What you will find is that bullet weights that are to heavy for the twist rate won't shoot well....but on the other side of the coin, normally you have little problem getting lighter bullets (read overstabilized) to shoot well in the faster twists......I am talking about potentially sub half groups in general for Ar15 class guns, and from 1/2 to 3/4 for AK & variant guns.

Paul

[Buck]

Bushmaster is also 1 in 9 which stabilizes 55-72 grains.
You need 1 in 7 for the heavier weights for the longest ranges.

[Brian in MN]

If you shoot the heavier bullets out of a 1 in 12 barrel they are tumbling by the time they are 20 feet out. Someone just demonstrated this to me this winter with a piece of cardboard. He was shooting a Galil and I was shooting a 1/9 Norinco 84S. We were both shooting the same 62 grain ammo. He was keyholing and I was not. Having said that, the accuracy of the Galil was more than adequate at 20 feet. In an emergency the heavier bullets would be really nasty at close range when fired from a 1/12 barrel.

[Packrat]

I believe the early AR-15s that the Army used for testing before adopting the M-16, and the early M-16s, had a 1 in 12 twist. The bullet was understabilized and would tumble almost on impact (or sometimes before impact, making it keyhole). Not good for accuracy, but tremendously effective as an anti-personnel round.

[pb]

My Bulg. SA M5 has a 1-9, and the Poly Tech type 56 has a 1-9. Both shoot 55- 68 gr just fine.

[KalashniKat]

I believe the early AR-15s that the Army used for testing before adopting the M-16, and the early M-16s, had a 1 in 12 twist. The bullet was understabilized and would tumble almost on impact (or sometimes before impact, making it keyhole). Not good for accuracy, but tremendously effective as an anti-personnel round.

The first AR-15's had a 1/14 twist but had problems with stabilization during artic testing, hence the change to 1/12. A bullet that keyholes is not going to penetrate deep enough to do effective damage to the target. There is no such thing as "over stabilization" or "under stabilization", the bullet is either stabilized or it isn't. 1/14, 1/12, or 1/7 doesn't have anything to do with terminal ballistics. Velocity does. Above 2700 fps 55 gr. from a 1/12 and 62 gr.from 1/7 both behave nearly identically, breaking at the cannalure and fragmenting. The new 77 gr. SMK will do the same down to about 2100 fps making it a better choice, especially for extended ranges or shorter barrels.