A point of clarification may be needed here judging from the fact that all postings in this thread seem to presume that it would be a
Webley
revolver to which such a shoulder stock would be attached.....
In fact, the shoulder stock to which Sardaukar linked in his initial post is actually a reproduction of an accessory for the Webley &
Scott
self-loading pistol (..... British terminology for
semi-automatic ......) of the type adopted by the Royal Navy
in 1912 and by the War Department in 1913, based on the Webley & Scott Model 1910 Self-Loading Pistol. (Indeed, since Webley
produced their first self-loading model in 1906, none of their self-loading pistols could be "antique" under Canadian law.)
The Naval and Military Webley self-loaders were chambered for a rimless .455 caliber cartridge similar to the .45ACP .... although
not identical. As an illustration of the Webley self-loading pistol in question, here is the diagram from the first entry relating to these
pistols in the War Department's
List of Changes in War Matériel and of Patterns of Military Stores -