Large hogs have a very thick, very tough 'shield.' Buck shot is fine, however, if shot in the shield, they will often run. Hogs are very tough. I have trailed them by blown out lung tissue. In addition, they often bleed very little...hard to trail. I used a 7 mm mag for years. the 7 mm is extremely powerful and fast. After having many run on me I decided to try something different. I switched to a 45/70. It puts them on the ground.