The .455 Webley Mk.I cartridge was adopted by the British Army in 1887, loaded with a lead bullet and black powder as propellant. With the introduction of cordite propellant this round was changed to .455 Mk.II. It had a slightly longer case, which was also used for the later versions (Mk.III to Mk.V), featuring different bullets.
All .455 British revolver ammunition was officially declared obsolete by the British military in 1950. Some manufacturers still produce this ammunition for older guns, although no new guns have been made for these loadings for quite some time.
|Designation||Manufacturer||Bullet weight, g||Muzzle velocity, m/s||Muzzle energy, J||Comments|
|.455 Mk.I||17.7||213||390||original black powder load|
|.455 Mk.II||17.2||177||268||original cordite loading of WW1 era|
|.455 Mk.II||Fiocci||16.9||259||566||modern commercial loading|