Ok, I'm very new to muzzle loading and casting so take this for what it's worth......I killed a pig a couple of weeks ago(the one that I posted the link to the picture of) with my 8 bore built by Steve and used a round ball cast of pure lead. The ball wizzed right through the pig, scraped the side of a gum tree about 20 yards beyond the pig and slammed into a cypress tree about 20 yards beyond that. As soon as I can get back there to dig it out I will post a picture of the ball. I killed a smaller pig that same day, but hit it in the face with grotesque results. During the deer season I killed a big doe and a small buck with this same combo.......both complete pass throughs. All that to say, I dont think you will have any penetration issues with the round ball on pigs and they are much easier to load.