The Spencer repeating rifle is a lever-action firearm that was first introduced in 1860. It was designed by Christopher Spencer and became notable for its ability to fire multiple rounds without needing to reload after each shot. The rifle uses a seven-round magazine, allowing soldiers to fire more quickly during battles, which was a significant advantage during the American Civil War. The Spencer rifle was chambered for the .56-56 Spencer cartridge, which was a rimfire round. Its innovative design and rapid-fire capability made it popular among Union troops. The rifle's effectiveness contributed to its use in various conflicts, and it is considered one of the first successful repeating rifles in military history.