Thread: F**ck'n CCI Primers !

I'm not saying at all that the example above has the cause that I'll describe but more of a generalisation - incorrect advise has floated around for ever that primers must be seated flush with the cartridge's base. This is totally wrong (except in the case maybe of the White River primers which may be deaper in dimension than the primer pocket).
Primers must be seated with the anvil in contact with bottom of the primer pocket. In most cases this will mean that the primer is below face. If seated flush and there is a gap between the anvil and the PP's base the force of the firing pin is mostly expended trying to push the anvil to contact the PP base.
Some primers IIRC early Murons needed a degree of crush to make the contact. I seat my LRPs (CCI BR-2s) with 2 thou crush and my SRPs at around 1.5 thou crush. However, working to these dimensions is beyond the average reloader's capability.

As already covered, excess shoulder bump is a potential cause of failed, or poor ignition.
Another cause, but these days shouldn't be common, is incorrect firing pin protrusion. This combined with excess shoulder bump is sure to give problems.