I encountered a problem once when trying to use large pistol primers in a cast bullet load.  I had a heavy 27# Wolf striker spring in my rifle, and the primer pockets were uniformed, maybe a little deep.  I thought the pistol primers were being pierced, but what was really happening is that they could not stretch far enough to contact the boltface with the firing pin sticking in the middle of them.  Oh, they came back and contacted the boltface, but they had to give somewhere in order to do it.  The dent of the firing pin was where they gave.  Pressure must've dropped some before that happened, wasn't a whole lot of gas escaped, but enough to leave a mark on the boltface.  As mentioned, it was cast bullet load, probably didn't produce more than 30,000psi.  With a full power load it may have allowed more gas to escape.  With a lighter spring the primers didn't tear in the middle of the dent.