Scarce Indian Wars Springfield Spencer .56-50 Rimfire caliber rifle. In 1871 Springfield armory altered 1,000 .56-50 Rimfire Spencer carbines manufactured during the Civil War by the Burnside rifle company to infantry rifles. This all correct Springfield Spencer rifle has approximately 98% barrel blue, visible receiver case colors, correctly operating action, “ESA” stock cartouche, serial numbers 30,974 on the receiver and barrel, correct rear sight, very good stocks with no cracks or chips, and original sling ring and bar. This is a key piece for any 1865-1900 collection.