Given that handguns are weaker weapons then long arms , we can set aside the common basura about "stopping power."
In my casual perusal of many after action reports, it seems the most decisive way to end a gunfight was a shot to the head or spine.Given that, why does the larger training community stress center of mass hits, then headshots?
Wouldn't the most logical setup be to aim for the head from the start, THEN take torso shots as the bad guy now begins to juke for cover or concealment? I do realize this is a tougher row to hoe training wise, but that's the whole point of effective training.