Rifled muzzle loader

A rifled muzzle loader (RML) is a type of artillery piece invented in the mid-19th century. In contrast to smooth bore cannon which preceded it, the rifling of the gun barrel allowed much greater range, accuracy and penetration as the spin induced to the shell gave it directional stability. During the 1860s and 1870s, Rifled Muzzle Loaders were used as field guns, naval guns, and fortress guns, until they were superseded by effective and reliable breech-loading weapons.

In naval service, the rifled muzzle loader and the concurrent rifled breech loader (RBL) generated a huge arms race in the late 19th century, with rapid advances in fortifications and ironclad warships.