Not sure if I would have started shooting just yet at that point ... but I do not believe he should be prosecuted.
Sorry to bump this older thread but I simply had to reply. Looks to me like he held fire till BG began to turn with a weapon. Hats off to him for the restraint. I'm a back shooter and in this instance would have felt justified with a headshot. The object is to stop the threat not see who can draw fastest: simply my opinion and take on the facts of life in the "new" old west. The gentleman was very lucky this ended up "good" in another sceniario this could have ended very badly with a lot of people hurt. If you feel the use of deadly force is justified use DEADLY force.