Bulges near the case head suggests either a chamber which doesn't support the case head, such as is the case with some pistols with heavily ramped chambers, or firing out of battery. Even then at usual 9 mm pressures with sound brass you would not expect cases to let go.
It may be that the brass was bulged in the gun it was first fired in. That much is suggested by the fact that it won't seat in your gauge. The bulging and whatever resizing may have cold worked it a bit. If it isn't seating properly in your chamber and your rifle is still firing it (ie out of battery) that may be what is caused the failure, especially if the stuff is running at high pressures.
Might be a case for tearing it down to save the projectiles and binning the brass.
