whatever weapon you choose you had better be aware of what it can and cant do.you should also be proficient with what ever you carry.personally i carry a .45, and if i have to shoot more than 8 rounds i'm in serious trouble whether i have a 9mm or a .45. shot placement is the key factor here.anyone that takes a bullet is going to be discouraged from continuing the fight.from a strictly ballistic stand point,the .45 will generate more energy and create a larger wound channel period.it will generate 100 to 250 ft lbs more energy,even with the 147 grain 9mm.now that being said, if you made a bad shot you a more likely to create greater damage to the person.i would rather have more energy entering the person especially if my life or the lives of others are at stake.in closing , the .45 was designed to STOP and KILL men.