Been using a 20 gauge with slugs and buckshotlately. I haven't seen a whole lot of animals shot with other calibers but the shotguns seem to put a big hole with little bruising around it. They knock the pig down real good too but thats mostly just shot placement talking. Doesn't matter what caliber you use (I'm talking about the big stuff, not 22s), you hit the pig in the spine or vertebrae, it's not going anywhere. Those hit in the vitals didn't go far either. Actually I don't think anything has made it 20 yards yet.