While I cannot identify this rifle, there were rifles similar to this made in Southeastern Kentucky's Cumberland Plateau region, particularly near the TN border. A couple of details, such as the more standard length of the iron butt plate return, cheek with flattened bottom edge, extended square shank on the percussion side lug, and "reasonable sized side facings' when TN side facings often left more room in front of, and behind, the lock create the possibility of a KY gun. You even see a few "inverted T" lock washers on KY guns from the Southeastern area, but they are smaller, less pronounced than on TN rifles. Even the tang style was used in some KY guns from that area. Pleasant Wilson of Clay County made rifles somewhat similar in architecture, graduated pipe spacing, somewhat similar tang, etc. with iron mountings...although this is not a P. Wilson rifle.
The gun appears to have graduated ramrod pipe spacing, becoming longer toward the muzzle, also seen on some KY guns from the area. From what I can see, I think the barrel may have originally been longer and was shortened at the muzzle end, destroying the original front sight and nose cap...which may also have been cast pewter...and throwing off the original pipe spacing. The rear pipe looks somewhat more TN in construction...but even there it isn't quite a "standard" TN rear pipe. Nice rifle, interesting, and without any barrel mark will probably be debated for some time to come. I'm not saying it is a KY gun...but it could be. Shelby Gallien