I chambered an 8 twist barrel in 6BR and I am having problems with pierced and cratered primers--My first load was 30 grains of varget rem 7 1/2 primers and 108 Bergers every primer pierced--Next load was 29 gr Varget velocity 2700 shot 4 shots every primer pierced plus a stuck case I had to tap out with a cleaning rod I think the barrel is an 8 twist It was originally a 6 XC I cut the chamber off and went with the 6br--Any help will be appreciated