I own one and they are a great shotgun. They have a lot more range then even the modern shotguns for turkey and such IMO. I load 110 grains of American Pioneer Powder then a 3-1/4 inch stiff wad, a match of #5 shot from a second wad, and then an over the shot card. I was rolling soup cans at 45 yards like there was nothing to it. At that range I could hit with as many as nine pellets in that can at that distance.
As for shooting roundball, I would not do it. Maybe like described, with a smaller ball in a wad, but I would not patch one. I have some smoothbore guns for that.