Here's the way I was trained:

If you must shoot a person, you do so only with the intent to STOP them from doing whatever threatening criminal thing it is they are doing (running at you with a knife, aiming a gun at you, etc). That's it: STOP THE THREAT. You don't factor in killing them vs. wounding them. Your goal and intent is to simply stop the threat.

The most effective way to stop a person when you are forced to shoot is to hit a vital organ. Shots to the arms/legs/shoulders generally won't do. You need to hit something vital. That will almost always stop them in the shortest amount of time. Now, in order to give you the best chance of hitting some vital organ, you ALWAYS aim for center-mass of the target (person). That's what we train to do - aim center mass. That way, even if you miss by a bit, there's still a good chance you'll hit the target somewhere.

Think of it like this: If you aim for a leg and miss by four inches, the target is not hit at all, and that bullet is going on down range to hit who-knows-what (or who-knows-who). BUT, if you aim center mass (center of the person's torso) and miss by four inches, you'll still hit the target and possibly a vital organ. You have a much higher chance of actually stopping the threat by aiming for center mass.

Here's the way I was trained:

If you must shoot a person, you do so only with the intent to STOP them from doing whatever threatening criminal thing it is they are doing (running at you with a knife, aiming a gun at you, etc). That's it: STOP THE THREAT. You don't factor in killing them vs. wounding them. Your goal and intent is to simply stop the threat.

The most effective way to stop a person when you are forced to shoot is to hit a vital organ. Shots to the arms/legs/shoulders generally won't do. You need to hit something vital. That will almost always stop them in the shortest amount of time. Now, in order to give you the best chance of hitting some vital organ, you ALWAYS aim for center-mass of the target (person). That's what we train to do - aim center mass. That way, even if you miss by a bit, there's still a good chance you'll hit the target somewhere.

Think of it like this: If you aim for a leg and miss by four inches, the target is not hit at all, and that bullet is going on down range to hit who-knows-what (or who-knows-who). BUT, if you aim center mass (center of the person's torso) and miss by four inches, you'll still hit the target and possibly a vital organ. You have a much higher likihood of actually stopping the threat by aiming for center mass.