.308's with 22 and 24 inch 1:12 twist bullets weighing 180 and 190 grains have won a lot of matches and set some records, too. 1:10 twist .308 Win barrels aren't needed unless bullets weigh more than 200 grains or the barrel's shorter than 22 inches.
US Navy Distinguished Marksman Badge 153
Former USA Palma Team Member
NRA High Power Long Range High Master
NRA Smallbore Prone Master