CLM: Is the blamed thing loaded?
It is not at all unusual to find a muzzleloading rifle, pistol or shotgun with a full load still in it.
Check with the rammer, or a length of dowel that just slips down the bore. Push it in until it stops. Mark that point on it with a piece of tape.
Now, remove the rod or dowel and lay it alongside the barrel. If there's quite a gap between the touchole and the end of the ramrod, you likely have a load in there.
Don't fire the laod out! God knows what's in there. Instead, ask a gunsmith to remove it. Ask him to save the ball, wadding and powder for you.
Years ago I read of a man who found a loaded revolutionary war era rifle. He pulled the ball with a worm then worked out the wadding and powder.
The wadding was very old newsprint. One piece was dated in the late 1700s!
Who knows, you may find something similar.
If it's a reproduction don't dismiss it as unloaded. Even today, modern black powder guns are occasionally found at gun shows with a load in them. The previous owner dies and his relatives sell his gun, or the owner simply forgot he left it loaded after hunting season.
NEVER assume any muzzleloader is unloaded.