These later 1850s-1860s half-stocked rifles, without decorative details that often show the maker's hand, are rather similar and difficult to identify. I cannot see any maker's name or initials on the top barrel flat several inches behind the rear sight, but please check that area again "just in case" and if anything is there, post a good, clear picture of it. Even if worn or partial, we may be able to figure it out.
The gun has a curved "fish belly" lower butt line, often associated with guns from Ohio and Indiana, but seen in other areas to a lesser degree. The longer two-screw [actually a tang bolt and rear tail screw] tang is most often associated with guns made below the Ohio River. The rather long cheekpiece is a little odd for the Midwest, at times seen on New York guns but also other places. So your gun has a good mix of details that makes it tough to pin down.
If I were to give it a SWAG answer, based on the mixed details, I'd think southern Ohio may be the most likely origin.
Shelby Gallien
