I beg to differ, if you get them in a wheat field with a lower recoiling rifle you can get more than 8 hits off.
I know that in close proximity in the woods I've run out of bullets in a bolt action, didn't have a miss, and still had pigs coming out. I would have loved to have had 8 rounds in a mag that day. Last time that I went out I could have easily gotten off 20 rounds (10 and a reload) with some pigs in the middle of a grain field. The smart ones ran off, the others just sort of ran around and stayed in range.
But, my pig problem may be different than yours.