You didn't say how high up you were, but I'm guessing at least 16 feet. With that said and considering the shot angle and short distance, you probably got one lung and the liver. Even though he was probably really sick, a rutting buck could go for miles like that. Hindsight is always 20/20, it happens to the best of us. As long as we learn from it...........it falls in the experiance catagory.