It is only flintlock long guns that are considered antique. Percussion long guns are modern in a legal sense (unless made before 1898)
Check the muzzle on your gun; the ones that I sold had a screw sticking into the rifling. It could not be loaded in that fashion. The screw only projected in a small amount and I was able to file the projection off with a needle file without damaging the bore. If my memory is correct neither gun had been shot before and both had the same problem. The front sight was held on with 2 screws and one of them was projecting into the bore
cheers mooncoon