Built a 223 with a Shilen Select Match barrel, 1 in 8 twist. It's a one holer at 100 yds. 69 gr SMK's. Will shoot sub 1/2 MOA out to 400 yds and 1/2 MOA at 500 yds. Never bothered with lighter bullets. Built another in 22-250, with a 1 in 10 twist, same Shilen SM. Will shoot 69 gr SMK's in one hole at 100 yds, but was tough to get it right(150 rds). Just started with Sierra 52 gr HPBT MK's yesterday. H380, 37.8 gr, and 38.0 will shoot one very tight hole. .169" and .160" at 100 yds. 1 3/4" at 300 yds. Federal 210 Match primers. Was very pleased. Love it when it's easy. Buy a good barrel, it's worth it in the end. Cheers, Ottway