The small lock bolt plate [or washer] is a style most often found on Ohio rifles. The double spurred guard and elongated side-facings where lock sits suggest a mid-century percussion rifle...but the barrel with a large bore and wide rifling grooves looks earlier than the rest of the gun, perhaps a re-use of an older flint era barrel on an 1850-ish percussion gun. The gun has a weakly grained [lower grade] curly maple stock, and has had a lot of cleaning and polishing to brass parts, all hurting its collector value. As mentioned by others, if the barrel has readable maker's name or initials it will add interest and some value. I'd think a $350-$400 estimate is about right due to its condition. Shelby Gallien