Hop,

Stopping power starts with 5000 Ft/lbs of energy. So that means a .458 class and up. I've twice competed in timed shooting events (Vintager and Big Game Club America) with paper targets. This was nothing more than an exercise of your stamina to shoot round after round after round. I'm still amazed at the man who competed with a .577

I still like the milk jug practice method best. Four water filled milk jugs from scattered from 25 feet to 50 yards. Start with the closes and work back. Take your time, don't rush and make every shot count.

When you can get 4 out of 4 you are doing damn good.