I think this is a cap lock style late 1800`s better pics would confirm for futher info.
Probably a, converted to percussion, flintlock rifle of North Western European provenance. Early 1800's I would say. It might be a so called "Jäger Büchse". There should be markings near the lock.
Belgium made many of these rifles for export.
The way the barrel is hexagonal means its pre 1800's as rifling was already available in 1801. but because its a percusion, it cant be older then the 1780's. very odd. never seen a percussion like it. it would make more sense if it was matchlock. Also the stock is very Arquibus style (1500's-1600's) soldiers used to have a stand for them as they were to heavy to hold while firing. very interesting.
With the double set triggers and stock, it seems like a sharpshooter/target rifle. It looks like a Pennsylvania/Ohio full stock of around .36 caliber. If you look up rifles made by Charles Meisner of Ohio or J. Ford of Pennsylvania, you'll sww rifkes very similar to yours.
Bumping this thread to ask if there are any proof marks on the barrel
near the breech ? This may give answers as to it's origin.
I'm guessing it may be an import as well.
Very nice piece, regardless.........