I have been shooting a Savege F class rifle in 6 BR and I have been pleased with the results (850 rounds). I was using Winchester Primers and was occassionally piercing a primer while using 30 grains of Varget. There were no other signs of excess pressure and I was getting 100 yard groups consistantly ~ 7/16". I changed primers to CCI magnum and did some new load testing. Wow, now down around 1/4" at 100 yards using the same Lapua brass and 107 SMK bullets and 30.2 grains of Varget. Maybe the extra 0.2 grains of powder or the primers, not sure. But pleased with the results. I have not shot enough to be really sure that the magnum primers will not be pierced, but so far so good.