A Rifled Breech Loader (RBL) is a large artillery piece which unlike the cannon and Rifled Muzzle Loader (RML) which preceded it, has rifling in the barrel and is loaded from the breech at the rear of the gun. Typical guns weighed 30 tonnes and had 10" barrels.

The spin imparted by the rifling gives the shell directional stability and greater penetrating power. Loading from the rear of the gun means the crew are less exposed to enemy fire, allows smaller gun emplacements or turrets, and gives a greater rate of fire.

The very first cannon of the middle ages were breech loaded, with gunpowder and shot contained in pots dropped at the back of the barrel, but the poor seals meant they were dangerous, wore quickly and could not be scaled to larger weapons. Whitworth and Armstrong introduced improved designs in the 1850s and 1860s. These were adopted by the British Army, but concerns about wear rates led them to revert to the RML in 1870. Only really when the interrupted screw appeared was the superiority of the design acknowledged.

These new guns lead to an arms race in fortification and ironclad warship design that lead to Dreadnaught and continued until the start of WWI.

External links

• History of the Gun