.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 US Navy & Palma Rifle Team Member
NRA High Power Master & Long Range High Master
NRA Smallbore Prone Master