Approximately 14,494 Spencer carbines in this configuration, with the Stabler cut-off, were manufactured for government contract by the Burnside Rifle Company circa 1865. This carbine has the standard manufacturer markings and features including three-groove rifling. However, it lacks any visible government inspection marks while having "crown" over "V" proofs visible on the top receiver and barrel breech. This may be one of the 3,500 contract carbines rejected by the government and believed to be privately sold.