A muzzle-loading rifle is a muzzle-loaded small arm that has a rifled barrel rather than a smoothbore, and is loaded from the muzzle of the barrel rather than the breech. Historically they were developed when rifled barrels were introduced by the 1740ies, which offered higher accuracy than the earlier smoothbores. The American longrifle evolved from the German "Jäger" rifle; a popularly recognizable form of the "muzzleloader" was the Kentucky Rifle. Although by definition they must be reloaded after each shot in a time-consuming fashion, they are still produced for hunting.
Comparable artillery pieces are termed rifled muzzle loader (RML).