A muzzle-loading rifle is a muzzle-loaded small arm or artillery piece that has a rifled barrel rather than a smoothbore. The term "rifled muzzle loader" typically is used to describe a type of artillery piece, although it is technically accurate for small arms as well. A shoulder arm is typically just called a "rifle", as almost all small arms were rifled by the time breechloading became prevalent. Muzzle and breechloading artillery served together for several decades, making a clear distinction more important. In the case of artillery, the abbreviation "RML" is often prefixed to the guns designation; a Rifled breech loader would be "RBL", or often just "BL", since smoothbore breechloading artillery is almost nonexistent (except in tank guns). A muzzle loading weapon is loaded through the muzzle, or front of the barrel (or "tube" in artillery terms). This is the opposite of a breech-loading weapon or rifled breechloader (RBL), which is loaded from the breech-end of the barrel. The rifling grooves cut on the inside of the barrel cause the projectile to spin rapidly in flight, giving it greater stability and hence range and accuracy than smoothbore guns. Hand held rifles were well-developed by the 1740s. A popularly recognizable form of the "muzzleloader" is the Kentucky Rifle, which was actually developed in Pennsylvania. The American Longrifle evolved from the German "Jäger" rifle.
Small arms
Like most early firearms, the first rifles were muzzle-loading, although this involved a lot of complication in inserting the bullet past the rifling, and clogging and cleaning problems were notorious. There are also muzzle-loading pistols and shotguns. The Minié ball of the middle 19th century increased the rate of fire of rifles to match that of smoothbores, and rifled muzzle-loading small arms were rapidly adopted. These long rifles and similar weapons were used from about 1700 to 1900, but gradually gave way to firearms whose projectile is loaded into the chamber via the breech, without having to pass through the barrel.
Artillery
La Hitte system
The La Hitte rifled guns were used from 1859 during the Franco-Austrian War in Italy. These guns were a considerable improvement over the previous smooth-bore guns which had been in use. They were able to shoot at 3,000 meters either regular shells, ball-loaded shells or grapeshot. They appear to have been the first case of usage of rifled cannons on a battlefield.
British Royal Navy
The muzzle-loading rifle was introduced into service in ships of the Royal Navy, after experimentation with alternative armament systems, after the failure of the Armstrong 100-pounder breech-loaders installed in 1860.
Until the middle of the 19th century Royal Navy warships had been armed with progressively larger smoothbore muzzle-loading cannon. These had by then approached their limit in terms of armour penetration, range and destructive power. It was known that rifled ordnance provided more accuracy, a greater range and more penetrative power, which was the rationale behind the development and on-board shipping of the breech-loading cannon developed by the company owned by Sir William Armstrong. These weapons, however, were dangerously prone to failure, frequently explosively, and an alternative armament became urgently necessary.
An initial attempt at an alternative was the 100-pounder smoothbore Somerset cannon, which, while it was an improvement over previous smoothbore guns of lesser calibre, could not penetrate armour of thicknesses currently being shipped by British or foreign battleships.
The type of gun finally adopted was a muzzle-loading weapon which fired projectiles with external studs which engaged with the rifling. This system was the "Woolwich" system; while it was possible with this system to fire shells at a higher muzzle velocity, and therefore with greater penetrative power, than before, the studs tended to shear, there was excessive wear of the gun liner, and the shells tended to wobble in flight. Furthermore, the muzzle velocity obtainable in these guns was no more than half of that obtained in interrupted screw breeched guns of the following century. There were several reasons for this: the shell could not be made to fit too closely into the bore of the gun, as it would not have been possible to ram it home; the velocity of a shell depends, among other factors, on the length of the gun barrel, and the need to load through the muzzle necessitated a short barrel so as to make the muzzle accessible to the loaders; later types of explosive were superior; and metallurgical techniques improved to allow a higher initial pressure in the breech of the gun.