The .455 cartridge was a service revolver cartridge, featuring a rimmed cartridge firing a .45 bullet at the relatively low velocity of 650 ft/s (190 m/s). The result was a cartridge and handgun combination with relatively mild recoil, but with good penetration and excellent stopping power. It was rated superior to the .45 Colt in stopping power in the disputed Thompson-LaGarde Tests of 1901, that resulted in the adoption of the United States .45 ACPcartridge. The .455 Webley remained in service with British and Commonwealth forces until the end of WWII.
The .455 Webley cartridge remained in service with British and Commonwealth forces until the end of the Second World War. Six main types of .455 ammunition were produced:
.455 Webley Mk I - 265 grain (17.2 g) solid lead round-nosed bullet propelled by black powder. Dating from the late 19th Century, all subsequent .455 designs used cordite propellant.
.455 Webley Mk II - 265 grain (17.2 g) solid lead round-nosed bullet propelled by cordite. There are minor differences between the Mk I and II bullet shape, though these concern the internal dimensions and so are not immediately apparent. Used cordite propellant.
.455 Webley Mk III - the famous "Manstopper" bullet intended for police, civilian and colonial use. Essentially, the Mk III was a 218 grain lead "hollowpoint" design. The cylindrical bullet had hemispherical hollows at each end - one to seal the barrel the other to deform on impact. This bullet was soon prohibited for use by the military because it was not compliant with the Hague Convention of 1899. Used cordite propellant.
.455 Webley Mk IV - 220 grain, flat-nosed wadcutter. Used cordite propellant.
.455 Webley Mk V - identical to the Mk IV bullet, but was cast from a harder lead-alloy containing more antimony. Used cordite propellant.
.455 Webley Mk VI - a 265 grain full metal jacketed bullet intended for military purposes, designed to comply with the Hague Convention. This bullet was used during the Great War and the Second World War. The propellant was cordite or nitro-cellulose.
The Italian firm of Fiocchi are currently the only commercial manufacturers of the .455 Webley cartridge.