I think of extremes. If an M1 shooting 30-06 @ 180g and about 3000ft lbs. muzzle energy will not always stop someone unless hit in a vital area, then why would a 9mm or .45acp at about 400 ft. lbs stop them...unless hit in vital area? It's all about shot placement.
Well, OK if they are at 500 yards or wearing body armor, then I will take an M1. Come to think of it I will always take the M1 but it is hard to carry in a concealed holster.