In all honesty, any gun that works will probably be sufficient for most scenarios. The reason I quoted just this text is because THAT is the most important factor of them all. No matter how prepared someone is, if you don't see it coming you're pretty much out of luck. If I were a criminal I would walk past my intended target and not make eye contact or look at them. As soon as they past I'd pull my gun from my pocket, turn around and tell them to stop and then cock the hammer so they can hear the gun. Once they stopped, I'd hit them in the back of the head and knock them out. At this point, they could have a 50 caliber machine gun and it'll do them no good. Most people won't pull out a gun and stare you in the eyes as they walk down the block letting you know well in advance what's going to happen. Now, they can show signs that something isn't quite right, but if you don't see it coming, no gun in the world is gonna help. If someone was walking past me, not paying attention to me and at the last second they pulled a gun and pointed it at my stomach or head, whatever, if I go for my wasteband, I'm gonna get shot so whether I have a gun that holds 1 round or 1,000 it's not going to matter. Now, once they get my stuff and run off I could grab my gun, but I'm definitely NOT shooting someone in the back. That could get me prison time. I think awareness of your surroundings is far more important than what type of gun you carry or what caliber it is. Most people won't ever even need to shoot in self defense, but if I have any gun, even my J frame, if I can get the drop on whoever is trying to get the drop on me, I can at least possibly get out of the situation I'm in. It's pretty hard to imagine a scenario before it happens, and when it does, it's gonna happen fast so who knows what I would or would not do. A few bullets to me, is better than nothing and I love revolvers. A lot of people love autos. Everyone should carry whatever they like and feel comfortable with, but be aware of what is going on around you. I see so many people, especially walking down the street in downtown Chicago that are completely oblivious to any and everything going on around them. I think that's more important than gun style or caliber any day because if you don't see it coming, who cares what gun you have, it's irrelevant at that point.