The Burnside carbine was originally invented by Ambrose Burnside – the man who would later command the Army of the Potomac and after whom sideburns would be named. Burnside came up with the idea while stationed in Mexico as a young officer, and resigned his commission in 1853. A substantial amount of money had been allocated by Congress to replace the Hall carbines, and Burnside hoped that his gun would be adopted. Despite his efforts, the attempt was unsuccessful, and Burnside sold his interest in the patents and company to one Charles Jackson in 1858.
Jackson continued to promote the gun, and his big break came with the outbreak of the Civil War. Under Jackson’s ownership, the company would manufacture 53,000 Burnside carbines by the end of the war, in 5 progressively improved variants.
The innovation of the Burnside was its use of a metallic cartridge to seal the breech of the weapon against escaping gas. However, the cartridge did not incorporate an ignition source. Each round had a small hole in the base, and a standard percussion cap was fitted to the outside of the breechblock to fire. This cartridge was innovative and effective, but would become obsolete by the end of the war, and no serious effort was made to continue making Burnside carbines after the fighting ended.