I will say this about the wild pigs: it gets me deep in the woods at least once a week with a gun in my hands. And yes, we eat them as well, but we're pretty selective in what we'll take. As for a "pig gun," there's a lot of mythology floating around. Hit right and they'll drop from just about anything. I actually killed one a zillion years ago with one ounce of No. 7 1/2 from a 20-gauge. We were bird hunting and he was in the wrong place at the wrong time. On the other hand, hit wrong I've seen them run off with half of their intestines hanging out. That said, just use what you like to use and try to put the bullet either in the CNS or take out the heart/lungs through the shoulders. He'll drop and paddle.
Just my $.02
RM
