Every state does have different laws. The one universal across the land is that your actions will be judged as being reasonable, or not.
I think that I miscommunicated my intentions. My point was that, unlike global warming, the concept that you will fight how you train is universally accepted, known and proven. If you have the mindset that you are going to shoot everytime you pull your gun and empty it, then there is a very good chance that is exactly what you will do.
When cops carried revolvers an accepted range practice was that when you reload, you put your emties in your pocket so that you don't have to bend over and pick them up later. Guess what happened? Dead cops with six empties in their pants pocket. You fight how you train.
When they moved to auto loaders they found that the magazines were subject to damage from being dropped, so they taught to put the magazine in your pocket so you didn't damage it, or get it dirty. Did we not learn a lesson? Guess what showed up?
With the knowledge that a pistol is inherently under powered for human sized animals, we used to drill two to the body, one to the head. If you shot, you shot two to the body, one to the head. Have we not learned anything yet? I can't get 10% of shooters to pass a bullseye range, let alone expect them to make a head shot under the crushing stress of a gun fight. Why would we teach that? Why would we teach to fire three rounds and evaluate? That is what we will do in a gun fight. We have evolved to reactive, shoot/don't shoot, targets and the concept that you shoot until the thing that is trying to murder you stops trying to murder you and then you stop shooting. We own every round we fire. We can send more down range, if need be, but we can never call one back. If one shot stops the threat, great. If it takes three magazines, that sucks, but you shoot until it stops and then if you are out of bullets you beat it with your with your empty gun if a threat still exists.
My original point was that every situation is not universal. You can't say "this is what I am going to do, no matter what". If you perceive a deadly threat your hands should be as full of gun as you can get em, as soon as you can. Reaction time is our friend. If a guy were to start running at me with a edged weapon I hope that I have some reaction time and can start putting hits on target before he ever gets anywhere close to me. Starting to shoot at 30 feet in that situation is not unreasonable. Shooting him at 300 yards would be unreasonable.
It does not matter where you are, your actions must be reasonable. Sometimes, unloading your gun is the reasonable response. Scoring a first round head shot, that immediatley incapacitates your oponent and then continuing to shoot him is not reasonable. Shooting an intruder that comes down the basement stairs at you is reasonable. Putting a gun under their chin and finihing them off is not reasonable.
That is all.