.455 Webley is a British handgun cartridge, most commonly used in the Webley top break revolvers Marks I through VI. It is also known as ".455 Eley" and ".455 Colt". The .455 cartridge was a service revolver cartridge, featuring a rimmed cartridge firing a .45-caliber bullet at the relatively low velocity of 650 ft/s (190 m/s). The result was a cartridge and handgun combination with comparatively mild recoil. The .455 MK III "cupped" cartridge was rated superior to the .45 Colt in stopping power in the disputed United States Thompson-LaGarde Tests of 1904 that resulted in the adoption by the U.S. of the .45 ACP cartridge.