I think you guys are mostly just disagreeing about terminology. The thing is that using guns in self defense is shaped by both of these facts: (a) shooting somebody is always deadly force, (b) you have a right to defend yourself from deadly force with deadly force, but you don't have a right to prevent the attacker from surviving; taking an extra shot just to make sure the attacker dies is murder.
Saying that guns are deadly force means that there is no "safe" way to shoot somebody, like the "shoot him in the leg" meme would have you believe. If you shoot somebody, that person may die, period. If you shoot somebody in the leg and they die, no court will take it seriously any defense where you say that you only meant to wound them and used only wounding force and the death was a freak accident so please give me involuntary manslaughter only please. No; once more, shooting is deadly force, and you should expect the target to die.
Yet shooting somebody doesn't guarantee that they will die; a sizeable portion of gunshot victims survive. The law places a huge value on life, even the life of the attacker. If you defend yourself with deadly force, you're not allowed to prevent your attacker from surviving.
So what do you do, concretely? (a) You aim at the center of mass, because that's basically the only reliable way to hit in a high-stress situation; (b) you shoot until you can see that they are no longer a threat; (c) you're done; call 911. If the attacker lives, they live; if they die, they die.