Thanks, I've been trying hard to ID it. It appears to have had a silver engraving plate on top of the barrel, now gone. I think the lock was replaced, but am not sure. It doesn't fit well in front. The brass buttplate seems unusual, not iron. Yet, I assume half stock or 3/4 stock rifles were pretty late, post 1850s? Maybe brass was more easily obtained by then, and was put on some rifles to be fancier? The two lines in the top of the buttplate look like some Lawing rifles, but anyone could have done that. I really like that it's 3/4 stock. To me, that is very unique and unsual.
I'm hoping Cades Cove, Dennis, or one of the other experts will weigh in.