See the thread "New Krieger barrel in AR-10 shoots"Might give you an idea of one option.
Brother just stuck a Kreiger in his old wore out AR-10T.He ordered it,he installed it.He loaded the ammo.He shot it.He got the bbl last Friday,the next AM he went out on the NE Colorado grasslands,on a private ranch,and shot this after he had 20 rds of break in clean and got on target.Range was measured with a Leica 1200.the 5mph wind was measured with a Kestrel.
He is not a sniper.He is not a veteran.He has never competed in a rifle match.
He builds roads.
He does ask me questions,and listens.I can't upload the pic here,as it is already on the other thread.Its 600 yds,one three shot group inside 3 inches.He e-mailed it to me to tell me he was happy with his new bbl.