I'll have a 30-06 and I'm not sure what he will have. I think we will have the choice of either tree or ground hunting. We will be on a friend's land who hunts hogs every now and then.
You could always do it the really old-fashioned way and get yourself a big ol' knife, lay on a low-hanging branch real quiet like and that goes above a place where you know hogs run, and when one comes under you, drop down, hold on, and stick.
Most calibers that work for deer will work on hogs. I've used 7-08, 30-06, 50 cal ML. Don't try head shots. Broadside through the shoulders and you can't go wrong. I've never had one run more than 50 yds with the above rifles.