This is going to throw a little gas on the discussion fire so to speak
but, I was at a local rancher's spread who raises Charolais cattle this morning. I was there to watch the slaughter and field dressing of a steer that I had bought a half interest in. 1250 pounds on the hoof at a year and a half old. Yes, these cattle grow up big. Anyway, the butcher used a .22 LR in a rifle (avg length barrel, prolly 18-22" or so) to dispatch the steer with one shot to the front of the head, midway between the eyes and where the horns would be. A single shot and that steer fell to the ground and was DRT.
I am NOT advocating that anybody carry a 22 LR for CCW or self defense. However, when you read the article NM linked, it's not so far fetched that a .380 was able to get the job done half of the time or so. I am not advocating anybody carry a .22LR for self defense/CCW unless that is all you have (feel sorry for anybody in those shoes). I was carrying a .45 CCW this morning btw. I guess what I am saying is carry what you feel most comfortable with but NM's points are still valid. If anything, they reinforce the importance of shot placement and the fact that caliber cannot make up for poor shot placement. I would never tell somebody not to carry what they feel comfortable with and neither IMHO is NoMercy448. What NM is saying, though, is an attempt to spur some discussion about caliber effectiveness and the fact (as born out by the linked study/paper) that a person can successfully defend themselves with a .380, 9mm, 40 or 45.
If you wanted to take away anything from the discussion, it should be that pistols are still only effective up to 60% of the time; shotguns and rifles are effective about 80+% of the time and nothing beats using good cover, good tactics and bringing several of your friends who also carry guns.
As always, YMMV and it is your rear end that you're betting on.