A possible maker for this rifle is John Maggard of Letcher County, Kentucky, down in the state's southeastern Cumberland Plateau region or "hill country" located one county above the Tennessee line. Born in 1796, his early rifles had walnut stocks, iron mounts, and three ramrod pipes, but later rifles used maple at times. I have not seen a Maggard rifle with a back-action lock, nor have I seen one this late... but he worked into the 1870s. While the triangular butt with straight comb/toe lines, long wrist, and long, large-bored barrel are all typical of his work, I have not seen this more elaborate cheekpiece on his earlier work, which had more traditionally shaped cheeks. My rifle has a tang of the same length, rounded tip, but straight sides rather than the small "step" about an inch and a half behind the breech... but that "step" was a common feature on some other rifles made in the area and could easily show up on a later Maggard gun.
Maggard was best known as a skilled blacksmith who made many edge tools for the locals, including shears, cow bells, and fine knives, along with a few guns when needed. He was capable of doing the good quality iron work on this rifle. The primary reason for thinking the gun may be by Maggard is the initialed barrel. The '"J" and "M" match the initials closely in shape and size on a rifle I have, which also has a similar small circle punched between the initials, but not the punched stars before/after the initials nor stars on muzzle. The bores also look similar with 7-groove rifling that is cut shallow.
Not a solid attribution, but a reasonable possibility.
Shelby Gallien