On June 23, 1874, Congress approved "For the purpose of testing Mr. Lee's breech loading gun under the direction of the Secretary of War the sum of ten thousand dollars is hereby appropriated." These rare Model 1875 rifles were manufactured by Springfield Armory under the supervision of inventor James Paris Lee. After one year, 143 rifles were completed using the appropriated $10,000, working out to a cost of approximately $69.93 per rifle. These rifles were found capable of a rate of fire of about 40 rounds per minute. The Model 1875 Lee drew inspiration from the Martini and Peabody series of single shot falling block rifles. The biggest change introduced by Lee was the use of a combination hammer and breech lever; from a decocked position, a push forward on the hammer drops and locks the breechblock while simultaneously ejecting a spent cartridge case, which automatically unlocks and closes when a round is chambered. Once closed, the hammer can be thumbed back to a locked half-cock position for carry or all the way back to full-cock for immediate action. Blade front sight doubling as a lug for a socket bayonet and 1,100 yard Model 1873 folding ladder rear sight. Serial number "67" marked on the right of the hammer and underneath the breechblock (requires disassembly to view). The upper tang is stamped "U.S." above "PAT. MAR. 16. 1875." It has two "U" marked barrel bands. The front band has stacking sling swivels, and the trigger guard has a single swivel through the front. The smooth straight grip stock is stamped with Master Armorer Erskine S. Allin's oval script "ESA" inspection cartouche ahead of the left stock wrist and a small "B" inspection letter ahead of the circled script "P" proof stamped behind the trigger guard. "US" marked buttplate tang.