Any hunting ammo with caliber .270 and above will work fine, just don't forget to aim differently, not like at deer. As it was said above already, aim at neck. Another good aim point in 1/3 of the line from ear to shoulder. Aim is not easy because pigs are almost constantly moving. If a sounder comes you will hear them from afar. A single old boar (or saw) might come silently. And good luck!