I have done some backyard testing with wet news paper, and a 380 will certainly penatrate far enough to kill, in fact FMJ ammo seems to do almost as good a job as some of the high dollar defence rds, also a hot 22LR will do the job, part of the problem with 380 gun is most are tiny little guns that hurt to shoot, so if your more than a few yds away from the BG you most likely will not hit the target at all let alone a well placed shot that will put them down, of course that really holds true with any tiny gun, in any caliber, now if you were to have a bit larger gun, like possably the Bersa, Sig, Walther, the gun would be a bunch easyer to get a good on target hit, because seriously I agree a 380 is a plenty leathal enough rd, the shot has to be placed were it will do some imeadiate damage, because the hole from the bullit if not in a vital area, will only bleed a little and will not stop a determind attacker, that being said it would seem a larger caliber would make a larger hole so the BG would tend bleed out faster, I guess if theres a bottom line to this its no matter what the caliber you carry you have to have good shot placement, and the bigger the bullit and the heavyer the gun the more chance you have of getting a leathal hit