300 Blackout Twist Rate

[newglockguy]

Would a 1/8 twist rate work for 300 or would I need to go with 1/7?

 

[helotaxi]

1:7 won't hurt anything. The standard twist when the round was developed was a 1:8 and it's only been very recently that I've heard of anyone going any faster than that.

 

[dubbleA]

I have no problems with a 1:8 twisted 9" AAC SBR shooting suppressed subsonic 220gr SMK, 225gr Hornady BTHP Match or the 240gr SMK @ 1050fps.

I am guessing the 1:8 might be borderline in some barrels thats why AAC went to a 1:7.

 

[68wj]

AAC released it with a 1/8 and most barrels were such. Then, sike, they started making their barrels in 1/7. Either should work for all but the longest subs, then the extra spin helps.

 

[helotaxi]

Extra spin never hurts. Especially when making sure you don't have a baffle strike in your can.

 

[MCMXI]

If you have reasonable expectations in terms of accuracy then 1:7 or 1:8 is fast enough. There's a move to go to 1:5 barrels but long 208gr to 220gr bullets will still yaw ... it's not a gyroscopic problem but some just can't be convinced.