I've never been shoot but i work in a ER and seen plenty of gunshot victims. I cannot tell you how many of the ones who got hit with small caliber did not sustain enough trauma to got them stoped at the time of the event. Some died but hours or even days later and if they had the oportunity to shoot back, believe me, they did! One can argue that a shoot in the correct spot will stop anyone and that is true even for a bb gun. That does not mean Im going to carry one! I have never been in a gunfight and hopefully never will but Im guessing that in a stressful condition , maybe a dark enviroment you will not be as accurate as in the controlled enviroment of the practice range and at least i want to be able to incapacitate the oponent as much as posible with the first hit. Personally, i will carry .45, .40 and maybe that cute .357 that i just got, based on what i have witnesed.