As a self defense weapon for a civilian, I think there's a lot of talk and theory over nothing.
I read somewhere that US police statistics say that the overwhelming majority of scenarios where guns are used play out at 1-3 meters and 1-3 shots are fired total over the space of a few seconds.
So basically any gun with do, shooter training is much much more important. Even luck is more important than the weapon itself.
My carry weapon is a Bond Arms .45/.410 derringer. It useless beyond 1-3 meters but deadly inside of that. I know it only has two shots but I'm not looking to get in a gunfight here. If one shot isn't enough ten probably wouldn't be either.