Re: AR 10 issues
Have you tried using commercial 165 match grade ammo?
I have a 21" Noveske barrel on a ArmaLite lower, a ArmaLite two stage I tuned. With DAG surplus it's a sub 2 moa rifle at 100 & 200 yds. With commercial match I'm able to get .7-8 moa, the shooters limit.
Check barrel...