If you want a new rifle, the Traditions Hawken Woodsman .50 is a good choice. It will shoot patched round balls and Hornady Great Plains lead bullets equally well. Its relatively inexpensive. Barrel is easily removable for cleaning. It's readily available. And will resell quickly since you will be asking only a portion of its already low retail price.
That was my first muzzleloader, and it wasn't a bad rifle at all for the price. It was minute of dessert plate all day long with patched round balls and the iron sights, and they were the easy click adjust ones, so changing zero for loads was a piece of cake. Think I paid $60, maybe $75 for it used and sold it for about the same several years later.
