The 1855 rifle was produced from 1857 until 1861. The first version produced had brass furniture. Inletted in the patchbox was a receptical for the detachable figure 8 sight that slipped on the front of the barrel. In 1859 the design of the rifle went through some changes. The changes were implemented in several steps. Two changed were the first modifications. The furniture was changed from brass to iron. The nosecap was not considered furniture and remained brass. The second change was to the rear sight. However since the design of the rear sight was not finished, the rifles were produced with no provision for a rear sight. These rifles were turned into storage at Harpers Ferry completed and inspected but with no rear sight. Later in 1859 the rear sight design was finished and production on new rifles continued with the new rear sight. The next change was to omit the patchbox. Then the long brass nosecap was replaced with a short brass nosecap. Then the patchbox was reintroduced with the opening enlarged. And lastly the short brass nosecap was replaced with an iron nosecap. All of these changes were implemented by the end of 1859. Meanwhile these first transition rifles were sitting in the racks at Harpers Ferry without rear sights. In the spring of 1861 the transition rifles were pulled out of storage and in March 1861 they were disassembled and the arrels were milled for the mortise and screw holes to attach the rear sight.
This example is dated 1859 on the barrel and 1860 on the lock. This has some issues. The stock was sportorised and cut in front of the lower barrel band. The forestock of the stock and the long brass nosecap are reproduction. The origional stock - from the lower barrel band to butt - includes the butt with the patchbox inletting. I did not see any inspectors cartouches in the stock. The barrel is full length and has clear proof marks and barrel date. The barrel is missing the rear sight and bayonet lug. The lock is complete with deep markings. It has the primer door and primer mechanism. It is missing both sling swivels. The ramrod is a reproduction.
This example has some issues. Still this variant were produced in numbers less than 700, many of which were present in Harpers Ferry soon before the abandonment of the facility in April 1861.