Come on, now. That story is a little shady. This feral dog is latched onto his wife's arm, attacking with enough ferocity and force to break bones, and he shoots it in the head with a .357? So, this fearsome attack was static enough for him to get a headshot? You said yourself that you'd need to "spray" at a dog, and would only get bad hits. Most dogs shake their heads pretty rapidly when attacking, and with his adrenaline pumping and his wife screaming... I dont know, man.
I'd not be too quick to raise the BS flag were I you if you've never had experience with feral dogs.
I shot a German Shepherd cross off of my own arm several years ago. 2 fast shots from a 1911 with Glaser's did the trick and I had a wicked bruise all the way around my forearm for days. And this one was allegedly domestic - although there had been reports of it and another chasing stock in the area.
I then drove it to the front yard of the owner, dropped the carcass next to his front steps and asked him if he ws going to call the police or should I...