While I don't have the "gun fights" under my belt the old man had, I have unfortunately been in a few in both receiving, vested thankfully, and delivering projectiles. While statistically what nomercy is stating may be true, having "been there done that" kind of gives me a slightly differing opinion than those statistics say. Now yes, a vast percentage of conflicts involving firearms in the civilian world are up close and personal. I believe the average is within 20 feet? Correct me if I am wrong there. Now, at 20 feet, pretty much any center fire will penetrate deeply enough to cause enough internal damage to stop an assailant. But the problem that is encountered is the exact same one that hunters encounter. Unless you cause an immediate dump in blood pressure, enough to disrupt brain function, then you have to keep shooting. Or you cause CNS disruption. Either one requires marksmanship as well as penetration and bullet opening performance. Now todays bullet technology has been greatly improved, especially in the last 10 years, since a lot of those statistics were gathered. But to say a .380 is going to penetrate and perform even as well as a 9mm is pushing the limits of ballistic sciences. Will a .380 do the job at arms length where you are most likely going to need it? Yes it should do well. But will that same gun/cartridge combination perform as well as a 9mm at 20 feet? Not likely. I doubt someones accuracy while under fire is going to be what it is at the range. Yes well practiced individuals should have the muscle memory to perform the basics. But speaking from unfortunate experience, it isn't going to happen like you think it's going to. I'm in no way saying a .380 can't do the job but I'm just not going to put my life on the line with such an anemic round. The 9mm is pushing it for me but I am extremely accurate with it and confident which is almost as important as the cartridge itself. If you aren't confident in the firearm you are carrying, you will damn sure break under the pressure of a gunfight.
All this is just my opinion and we all know what opinions are compared to.