You paid a fair price for the rifle, I assume it is a percussion gun, not flint. Although relatively inexpensive, these guns tend to be pretty accurate. The most important part about owning one is learning to clean it properly after you shoot it. Black powder and Pydrodex are really corrosive, left uncleaned or improperly cleaned after a shooting session your rifle will be worthless in a few weeks.
Black powder guns are like people, each has a different personality and may shoot great with one load and awful with another. Once you hunt around for the load your rifle likes, you will know what to shoot in it forever. By changing the load I mean varying the amount of powder, ball and patch size or conical bullet size or design to see what shoots best. You could also ask the previous owner what has favorite load was to save some time.
