Again, it depends on the environment in which you're carrying. Where I live (East Texas), the three feral species to be concerned about are dogs, hogs, and people. A good 9mm or .357Mag works well for all three in a SD situation. Bigger animals require bigger loads. Remember, hunting requires a one-shot terminal stop.....SD is shooting the threat until it stops being a threat (if it dies, that's its own choice).