My mother was a ace shot on Purdue rifle team. In fact they got confused because of the spelling of her name and tried to draft her.
She tried to teach me, but dad intervened.....I've forgotten everything I knew plus some.
However, some have suggested he shot TM while he was on top of him. That could very well have happened. I have my doubts.
GZ could have shot TM from a distance, and it still would be a justifiable self defense shooting. The problems, would be if he made any statements and if the science stated otherwise.