Evan: I would not bother shooting buck and ball, even in Florida. Yes, the deer are small, but that size rifle will deliver a good expanding round lead ball at those ranges and kill very well. I do think a .50 is small to be using on wild boar, based on my own experiences. If your gun will shoot a short bullet, like the REAL slugs, I would recommend using that instead of a PRB for boar.
Basically, to give you an answer, you would load a .490 PRB in the gun, following it with some buck shot, probably .24" in diameter, to get 4 or 6 buckshot on top of the ball. Then seat a over shot card, or felt wad on top of the buckshot, to keep if from moving in the barrel. Some people get away with simply pushing some leaves down the barrel on top of the shot. That small shot is not going to do much beyond 20 yds for you in wild boar, and at that range, they will hit so close to the PRB wound that they won't make much of a difference. Either your PRB delivers a killing wound, or the boar runs off wounded, to die somewhere else, or to recover over days and months. If you use the larger sized buck shot, you can't get two of them to seat side by side in that barrel, and they will be even less effective, if that is possible. Just remember, the larger the shot, and the more shot you load, the more pressure is created, and the more felt recoil the gun will have when fired. I think, personally, that buck and ball loads make much more sense in 16 and 12 ga. smoothbores. Even in a 20 bore, its hard to find a load that does much to improve the killing powder of a single round ball. In the 20 ga., the round ball weighs 3/4 oz.; in the 16 ga. it weighs an ounce; and in the 12 ga., it weighs 1 1/8 oz! In your rifle, that round ball weights about 4 tenths of an ounce. It is no cupcake, but I think it will perform better on both deer and boar without the buckshot in front of it.
