Actually the biggest pig we shot was killed with a .223 behind the ear. Though we quit using it after we had too many run off after being shot with it. We had some we shot in the head and they just shook their head and walked off. We had one in a trap we had to shoot 3 times before she stayed down. I now use a .35 or .450 and I don't have to worry about where I shoot them. We shot one last weekend with the .35 and it dropped in it's tracks with it's lungs and heart turned to mush.