When I use standard cci small rifle primers in my ,223 and in my 6 BR. they look like yours do and when I use 450's they do not crater unless I am way over the top with pressures.I reloaded some ammo for the new custom built 6 BR, 107 Sierra MK, 27.0 - 30.0 grains of Varget, virgin Lapua brass, and CCI 450 primers. Doing 3 round groups from 27 to 30.1 grains in .3 increments. At 27 grains I was already getting primer cratering. When I got home, I measured the boltface firing pin hole and it measures .076" and I also measured a boltface from the .308 that uses a standard large rifle primer, it measures .074" and it seems both boltface firing pin holes are for large rifle primers. I did some googling and I see that the small rifle boltface firing pin hole is .060" and would this be the issue? Send the bolt off to be bushed and get a small firing pin in it?
Here are the pics of the cratered primers.
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I reloaded some ammo for the new custom built 6 BR, 107 Sierra MK, 27.0 - 30.0 grains of Varget, virgin Lapua brass, and CCI 450 primers. Doing 3 round groups from 27 to 30.1 grains in .3 increments. At 27 grains I was already getting primer cratering. When I got home, I measured the boltface firing pin hole and it measures .076" and I also measured a boltface from the .308 that uses a standard large rifle primer, it measures .074" and it seems both boltface firing pin holes are for large rifle primers. I did some googling and I see that the small rifle boltface firing pin hole is .060" and would this be the issue? Send the bolt off to be bushed and get a small firing pin in it?
Here are the pics of the cratered primers.
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