Smooth bore percussion cap ID

[Eldudderino]

So, I have this thing..she’s pretty rough. It has a 36in barrel, smooth bore, internal diameter is .677, and it does not have sights. Any ideas of what this could be?

 

[Loyalist Dave]

Looks like it might have been a trade gun, based on a British artillery carbine.

LD

 

[loflyr55]

Cut down M1842? Or Macon alteration?