A few years back, I attended a defensive shooting class where one of the students asked an instructor where they should aim if the badguy was only presenting a partial target. The instructor had this to say, and it has stuck with me ever since:
If you can hit him in the meat, take the shot. You might get a more important piece of meat to shoot at next.
We all tend to think that if we need to use our gun in self-defense, we’re going to get a “classic” bad guy presentation, where we get a full presentation of the upper thoracic area to do a bill drill at five yards into, and then cooly re-holster our gun while checking to make sure that everyone around is 1) okay, and 2) saw how badass we looked smoking that mugger.
The reality of self-defense is often a lot uglier than that, which is where the real concept of center mass comes from. We think “center mass” means “center mass of the person”, aka the upper thoracic cavity. The reality of “center mass” as it was taught to me means “center mass of the available target” – or more simply “the biggest part you can hit.” Of course, the odds of any one of us getting into a two way gunfight as a civilian are pretty low, but it’s still a good thought exercise. People have been successfully conditioned by TV and movies to not shoot through concealment at people to the point where there are documented incidents of people taking cover behind stuff that shouldn’t stop bullets…and the badguys don’t shoot through it.
So how does this come back to armed self-defense? If someone’s trying to kill you and you can put a bullet in their meaty bits, you should probably do that. If the important bits are available, shoot him there. If not, shoot what you can get, and hope something more important comes up next. After all, if someone’s trying to kill you, you should try and kill them right back.