Poor groups with two Grendel barrels.

[Allen Roberts]

Thanks for your input. I am trying to trace accuracy problems on two barrels using the same upper/lower build. Aero precision upper, Anderson lower, nickel bcg, 2-stage RR trigger etc. Reviewing the situation 1) gas block / both barrels dimpled, block itself firm, but block/ tube slack and a lot of play on the receiver end.2) These are 20 inch rifle gas setups, but they would short stroke using rifle length springs. When I relaced the rifle length spring with a carbine length sling, short stroke problem was instantly solved. Any suspect area here? 3) cheap compensator w/ linear noise hood used on both barrels. Any suspect here? Same different ammo, maybe some improvement. I realize I may be the constant suspect culprit creating poor groups. I want to try to find that out.