Yes over pressure. I stopped using super fast burning powders in my pistol cases. I switched to IMR 4227 and have really nice consistent groups. They don't have the pop but 210 gr bullets are flying 1250 fps that's fast enough to do what it was meant to do. I don't like having to hammer out cases that's not a sense of security. PMC factory loads for the 41mag are pretty consistent and have around 1350 fps no swelling. Not a bad round for hunting. I prefer to build my own though.