Discussion Starter · #1 ·
Last fall I loaded some .223 ammo using Sierra 55 gr. flat base lead nose bullets with 21.9 gr. of Vith N-130, which according to the Sierra book should give up 3000 fps. Shooting my Savage Mod. 12 (9" twist), I can usually hit somewhere from point of aim to 1/2" out @ 100 yds (with 2 bags, of course). When the rifle gets hot, after 16 rounds, or so, some of the bullets are just not hitting the target or backstop, which is 3' X 3'. Some time 1, 2, or 3 bullets out of 4 will just go some where else, the one(s) that hits will be nearly on point of aim. After shooting, the case is not even warm, but there is a slight cratering of the primer, no hard extraction or pressure marks on the cases. These rounds spent the summer in my workshop with temps near 100 at times. The tech guy at Sierra suggested copper fouling, I scrubbed the heck out of the barrel, no change. Any ideas? Thanks.....