The percussion rifle is a rifle that uses a percussion cap instead of older flintlock or matchlock variants. Faster reloading and fewer moving parts made this rifle more versatile and rugged compared to other single-shot rifles. The U.S. adopted the percussion system in 1841 and produced an infantry rifle that same year. This was a .54 caliber, 33-inch barrel percussion rifle. The new arm was very popular, since it was accurate and easy to handle, and its browned barrel finish contrasting with the bright brass furniture gave it a pleasing appearance. It won fame in the Mexican-American War with Jefferson Davis’ regiment of Mississippi riflemen at the battle of Buena Vista, and its continuing popularity was such that most Confederate rifle manufacturers later copied its overall style. Some were later converted to .58 caliber and fitted with long range rear sights, but those used at Mill Springs seem to have been the original .54 caliber variety, which had simple notch rear sights.