The course ingraving, and rather crude furniture, suggests either a trade gun, or an American made musket, or fowler. The forestock being cut back, could indicate it saw some military service. A check of the bare section of the barrel for remnants of a bayonet lug would be a good idea.
The front sight being set back is pretty normal, but once again, is more common on guns designed for a bayonet.
Hungry Horse