I always thought the "x" in the middle of the torso below was what the firearms instructors were telling me to shoot at when they said "center mass." I guess I never got caught up in whether it was actually the center of the body, or if it was the quickest way to stop a threat. I just thought the idea was that shooting skills diminish under high stress with a moving target and aiming for the biggest part of what you could see was the most effective way to get hits and not shoot bystanders. I'm not a firearms trainer or expert though, and many of my targets looked like shotgun patterns.
1) Mid-chest. 2) It's a big area, full of vital stuff, surrounded by perpetrator; if you get close to what you were aiming for, you'll likely still hit Bad Guy. Also, it's close to where you're already looking if you're doing the right thing and watching his hands.
How much do you want to spend? You can't do better than Gunsite in Paulden, AZ. There's also Boone County Sheriff and Gunsite instructor Ken Campbell, who runs something of a satellite campus just up the road from you. They're not cheap, but you're asking important questions and answering them incorrectly could be financially costly and emotionally crippling.
