I'm loading 50cal bullets in sabots for a break action H&R slug gun. Accuracy seems to improve with higher velocity. I'm already pushing max recommended powder. What are the signs of overpressure in a shotgun hull? I'm looking for loose primers, and I inspect for a lip or bulge where the plastic meets the brass. Never reloaded for shotgun before, so I don't know if there's anything else I should look for.