The Webley–Fosbery Automatic Revolver was a unique semi?automatic revolver designed in the late 19th century by British officer George Vincent Fosbery and produced by the Webley & Scott. Introduced around 1901, the revolver used the recoil from firing to automatically rotate the cylinder and the hammer, combining aspects of both revolvers and semi?automatic pistols. Its distinctive zig?zag grooves cut into the cylinder interacted with a pin on the frame; when the upper portion of the gun slid backward under recoil, this mechanism rotated the cylinder and prepared the next shot. Chambered most commonly in .455 Webley (and later .38 ACP), the revolver was known for its smooth trigger pull and excellent accuracy, making it popular in target shooting competitions. However, it was large, relatively heavy, and more sensitive to dirt or improper grip than conventional revolvers, which limited its military practicality. Production remained limited, and although it appeared during the era surrounding World War I, it was never widely adopted by armed forces, remaining instead a fascinating and mechanically innovative curiosity in firearms history.