The Spencer repeating rifles and carbines were 19th-century American lever-action firearms invented by Christopher Spencer. The Spencer was the world's first military metallic-cartridge repeating rifle, and over 200,000 examples were manufactured in the United States by the Spencer Repeating Rifle Co. and Burnside Rifle Co. between 1860 and 1869. The Spencer repeating rifle was adopted by the Union Army, especially by the cavalry, during the American Civil War but did not replace the standard issue muzzle-loading rifled muskets in use at the time. Among the early users was George Armstrong Custer. The Spencer carbine was a shorter and lighter version designed for the cavalry.