I have a CCW permit, I own and am expert using several firearms and I have combat experience. But I only carry if I am riding my bike alone, or out in the boonies in pursuit of the Great American Photograph. In that case, it would just be me defending me, and not me defending the public. When I do, I carry an M9 in a little case on my bike, or under the seat in my car.
But I thought about your very question when that crazy guy shot up the movie theatre in Colorado. I decided to give it some real thought and establish rules for myself just in case it ever came up that I was armed and somebody started shooting.
And I realized that my own rules about it would probably prevent me from doing much in most public places. I would have to be in position and close enough that I could get off at least three rounds to disable or kill (I would hate to miss, or piss off, a lunatic with an automatic rifle). As a civilian who has sort of lost the edge, that would have to be pretty close with my M9 and I think that would be a stretch anyway considering he would not be standing still, my heart rate would be about 300 etc. Plus, I would have to be metaphysically certain that I would not hit somebody else. In a public place, I am not sure I could make that guarantee to myself. And my M9 is really too big to carry in public, so it would wind up being [I own these] a compact .45 or a small .380 so I would have to be even closer and if it was a .380 I am not sure it would knock down a crazy man at any distance unless I could hold it against his head . Finally, I would have to have some reason to think that the cops were nowhere close. I don’t want them thinking the good guy with a gun is a bad guy, and if the cops are close I figure they will be in a better position to do the right thing anyway so why not wait?
So the truth is, as much as I might want to be helpful to others, if I had been armed with a pistol in the movie theatre in Colorado or something similar, I might just have gotten the hell out of there or if I couldn’t get out, I would have gotten out my gun and hunkered until he was right on top of me.
In school full of little kids, I would probably be a little more aggressive, but even then, I would worry about shooting a little kid or a teacher by accident. No good.
And if it was some moron stealing an old lady’s purse or something, I would just beat the shit out him.
So we can talk all we want to, but if you think about, concealed carry should be for the most extreme circumstance of personal defense. Everything else is a little risky in my opinion.