My Model 10 .223 bolt action shot like crap. No amount of new load combinations with bullet weights, powders, charges, primers, seating depth did any good. I finally had enough and ordered a new barrel. The original was a 22 inch sporter with a 9 twist. I ordered a 26 inch varmint with an 8 twist and it is SWEET. Five shot groups at 100 yards are covered with a dime. 75gr A-Max over BL-C(2). I'm likin' it.