Bullet style and type will play a factor. There will be a large difference between a round nose lead slug and Hydra-Shok or XTP.
I fall into this school of thought...
being a high level trained military corpsman, and trained to treat all sorts of wounds on the battle field...
its easily to learn, that just by reverse engineering a wound in your head.... you can figure out shot placement location and what kind of bullet to use.
easy to do if you are taught about A & P....
I like XTPs... a LOT... if disabling the attacker is what you need to do to defend yourself or your family and loved ones.