GunBum
Active Member
One possibility that’s been overlooked so far…
If the port pressure is too high, the bolt can unlock before the pressure in the chamber/barrel fall far enough, and the case will bulge as it extracts. This may have nothing to do with firing pin bounce and/or bad primer seating. The first round may have been the one with the high port pressure and the extra recoil cause the shooter to bounce the trigger and do a quick double tap.
If the port pressure is too high, the bolt can unlock before the pressure in the chamber/barrel fall far enough, and the case will bulge as it extracts. This may have nothing to do with firing pin bounce and/or bad primer seating. The first round may have been the one with the high port pressure and the extra recoil cause the shooter to bounce the trigger and do a quick double tap.