Homer's Pictures.
Note the slight cratering - sign of excessive pressure, excessive pressure for the primer being used, or slightly weak firing pin spring, which is what I'm reading by the 'other' signs. I would try a diferent primer, with a stronger 'cup', ie: another make of magnum primer.

Also,there appears to be a little dimple in the middle of the pin strike, which appears in some to be a tiny hole. Dimples are usually caused by a small tit on the end of the pin, which is caused by leaking or blown primers erroding the pin's nose. It only takes one or two to do this.