G-Man is correct- it depends on what you mean by "Tennessee/southern mountain." Guns were undoubtedly being built in the Southern mountains from the time the first gunsmiths or blacksmith/gunsmiths moved there in the 18th century. The Jos. Bogle rifle, which we believe dates from the early 1790s, is the earliest documented Tennessee "mountain" rifle. But it is a transitional piece, reflecting Bogle's training probably in Virginia and is not what most folks think of as a "mountain" rifle. If, David, you are referring to the long, skinny rifles with iron furniture and banana boxes, Nate is correct - 1820 to 2012 (and counting). Certainly, as Tim points out, there were many guns made elsewhere in the South (Virginia, the Carolinas, Georgia, etc.) much earlier than the time when the "Tennessee/southern mountain" rifle presumably appeared. If you are thinking more of iron furniture than architecture, there is every reason to assume that iron-mounted rifles were being made in the South by the third quarter of the 18th century.