1:7 or 1:9 for 14.5" Grendel barrel?

[m796rider]

Hey all,

What is the better twist rate for a 14.5" Grendel barrel: 1:7 or 1:9? Let's assume those are my only two options, given how I'd like to provision my upper. Thanks.

[Bill Alexander]

1 in 7.5

7 will run at 10" but 9 is for 20" and up

[VASCAR2]

Is the twist required for the 6.5 Grendel different than with 5.56. I assumed the 1 in 9 twist in a 16" 6.5 G barrel would be good with 85 grain to 123 grain whereas the 1 in 8 or 1 in 7 would be better with the longer bullets from 100 grains to 140 grains. My 1 in 9 16" Shaw barrel shoots better than I can hold it so I'm not concerned that I might not have gotten the optimum twist. I could see how a faster twist in a shorter barrel might help stabilize long high BC bullets in short barrels. I ask because I like to learn as much as can about ballistics.

[m796rider]

It looks like I can only get the 1:9 twist. Will I still be OK in a 14.5" barrel? My ammo will be almost exclusive Wolf 120MPT and Hornady 123 Amax. Thanks.