Cartridge for the Webley-Fosbery Automatic Revolver and Webley semi-automatic pistols. Not interchangeable with .455 Webley revolver cartridges despite similar caliber designation.
Type: Pistol
Introduced: 1900, United Kingdom
Parent case: None
Standardization: Obsolete / Non-standard
Bullet diameter: 0.454" (11.5316 mm)
Case length: 0.927" (23.5458 mm)
Max pressure: 25,000 PSI
Rim type: Semi-Rimmed
Primer: Large Pistol
Typical twist rate: 1:20
Muzzle velocity: 700–750 fps
Muzzle energy: 239–280 ft-lbs
Effective range: 50 yd
Common bullet weights: 220, 224 gr
Primary use: military
Production status: Obsolete
Also known as: 455 Webley Auto · .455 Webley Automatic
History: Webley's semi-automatic pistol cartridge variant, developed for the Webley & Scott self-loading pistol adopted by the Royal Navy and Royal Flying Corps in WWI. The Auto designation distinguishes it from the rimmed Webley revolver cartridge. Used by British aviators as a sidearm during aerial warfare.