[312shooter]

Good on ya for catching this, if you have a gen1 or 2 glock it might be an unsupported chamber bulging the brass. Take some measurents of the area and compare to the schematics in your load manual. Resizing bulged brass can get troublesome as it will fold over itself and cause a weak point in the casing. I've had one or two lock up my action tight as they get jammed up in the chamber. Worst case scenario is you need to push the brass through a lee crimp die in reverse or buy a bulge buster.