If escape is possible, i.e. attack on the street, then multiple shots to the body should give one the required lead. Cornered in the home, or otherwise, if there is still a threat after the body shots, then the shot to the head is more justifiable. Then again, if there is still a
threat, it is still going to be tough to do the headshot anyhow. Although I do believe that it is better to be judged by 12 than carried by 6, finishing the bastard off in the absence of continuing threat ain't gonna look in front of a jury. Real Life 101, people for reasons good and bad are not going to carry or train with "appropriate caliber and handgun combos" 100%. People also count on the deterent effect; witness the number of crimes thwarted by the mere presence of firearms according to the N.R.A. My dear old departed Granny had a break-top 32 which she planned to stick in the housebreakers face, unloaded, when the time came. I realize the problems with this approach, but there is some validity to it and Granny wasn't alone in her thinking. Bottom line, shoot to the breadbasket 'til bad guy drops. If that happens before that loud click, then leave, call 911, keep bastard covered and/or shoot again as needed, in the order needed.