I am relatively new to loading for shotgun. Recently I loaded up 100 rounds of trap loads using once fired Federal hulls, #8 shot over 700-X powder, a load I have used before. Finally got out to the trap range only to find the crimp on about 10% of the rounds had expanded (see pics). All rounds shot fine, even those with bulged crimp. Any shotgun loading experts out there know what I am missing here?