This is a likely one-of-a-kind U.S. rifle-musket converted to the Merlett breech loading system for use with .58 rimfire cartridges c. 1868. John Merlett of Bound Book, New Jersey, obtained U.S. patent number 81,283 dated August 18th, 1868, in relation to this breech loading firearm design. At the conclusion of the Civil War, the U.S. Government found itself with a surplus of hundreds of thousands of muzzle loading rifle-muskets that were quickly becoming obsolete due to the introduction of breech loading cartridge arms. The most cost-effective solution to keep up with the rapidly advancing arms technology was to convert these muzzle loading rifle-muskets to breech loaders, and they entertained numerous inventors' designs for potential systems of conversion. This Merlett patented breech loader is one of the many ideas that got thrown in the hat and the only example known to this writer to exist today. When the hammer is cocked, the breech block swings to the right automatically for loading, under pressure from a spring, and has a built in spring-loaded extractor. The hammer uses a linked locking mechanism (broken, no longer attached to the hammer) that interfaces with the right rear edge of the breech block. The lock is marked "1864" at the rear with "U.S./SPRINGFIELD" at the center. The conversion breech section has no visible markings.

Good with scattered dark colored light pin-prick pitting, and the upper tang sits slightly proud. Stock is very good as period refinished, with numerous scattered scratches and dents, mild wear, and a crack on the left between the rear barrel band and front lock screw. The breech block locking piece is broken/partly absent and falls out when manipulated by hand, the spring-loaded breech block sticks, and the extractor is seized, otherwise mechanically functions. This prototype Merlett breech loading conversion gun serves as an important evolutionary piece in firearms history!