All things being equal, the reason a .45 works better in the game field than a 9mm is due to this simple fact;
The vast majority of people react "psychologically" to being shot whereas an animal only reacts "physiologically" to being shot.
Animals don't feel pain quite the same as humans do and they certainly have no ability to respond emotionally, so getting shot either shuts their system down or it doesn't ..... will or determination plays no part in the matter.
