The rarest variation of the Webley-Fosbery automatic revolver is the .38 ACP model. Only 341 of these were made by Webley, in an attempt to compete with the new semiautomatic pistols appearing on the market - most notably the Colt Model 1900 and Model 1902. The Colt was chambered for .38 ACP, a remarkable cartridge for its time - high velocity and semi-rimmed. Webley figured that an 8-shot Fosbery type revolver would offer the same capacity and ballistics as the new Colt, but in a revolver format familiar the the British market. The design could load cartridges individually, but also offered use of an 8-shot moon clip. Unfortunately for Webley, British legislation in 1903 hampered civilian handgun ownership and the military was not interested at all because the bore was too small. Of the 341 originally made, some were finally converted to .455 caliber models after years of sitting unsold in Webley's warehouse.

This model makes a notable appearance in Dashiell Hammett's novel "The Maltese Falcon", which quite specifically identifies it as an 8-shot, .38 caliber Webley-Fosbery. In the movie version, Humphrey Bogart mistakenly says it is an 8-shot .45, however...