The rifle, and particularly its cast nose cap, reminds me a bit of the work of Washington Hatfield of Indiana, who was trained in Fentress Co., Tennesse and soon after moved with his family up to Green County in southern Indiana to live and work. This rifle was NOT made by Hatfield, but the thought here is that there are obvious Tennessee details in the rifle with the walnut and iron, rear pipe arrangement, large side facings, pinned butt and toe plate, etc. and at least one major unexpected detail in the lower butt and forestock molding comprised of a flute with incised line above. A lot of backwoods Tennessee gunmakers didn't get that fancy.
The gun also looks very late to me, with its exceptionally thin butt, pushing it to after the Civil War. The gun could have been made by a Tennessee trained gunsmith who left a more remote backwoods area and moved to find better farmland and a better future, as Washington Hatfield did, and ended up in southern Kentucky, or perhaps southeastern Ohio or southern Indiana, or some other such "improved" rural area where a little more sophistication was expected in local guns, such as the unexpected lower butt/forestock molding lines, but the sleek "southern" style was still appreciated.
Shelby Gallien