HERE is a good read with regard to “stopping power”; that mythical term gunwriters have used for years in an attempt to describe something they don’t understand. Reichert does what I think is a good job of laying down the facts with one exception; he does not talk about pain. From a defensive handgun standpoint, pain is your friend because your intention is to stop your attacker. If you cause enough pain you can make anyone stop what they are doing and the purpose of a defensive handgun is to “stop!”
I’m not claiming to be an expert in this field but common sense is hard to ignore. American Rifleman magazine will soon be running a feature article on “stopping power” that takes a unique approach to answering the question. In that article you will be able to review the test results of 100 defensive handgun loads.