Personally, I think if you go with any quality ammo it’s the Ford, Chevy, Dodge argument. To me the two most important factors are shot placement and does your gun cycle the ammo, think follow up shots. As a first responder I have seen what various calibers do to the human body. Really, it’s about shot placement. If the first one doesn’t drop them you need follow ups. Fine motor skills go out the door in SHTF situations, so really multiple shots are highly likely.