Enchanted Webley Revolver

Post First World War, Scotland had a lycanthrope problem. The massive movement of British troops around the Empire had exposed some to events, forces, and powers that had been quiescent until then.
One of these troops was Lieutenant Douglas Mackenzie, who, while assigned to Allenby's forces in Palestine, had been badly mauled by...something. He was evacuated to England, and sent home to recuperate. After the first full moon back in the Highlands, he transformed into a wolf, killed some of his Father's (the Laird of Glenbairn, and and a retired Lieutenant Colonel of the Gordon Highlanders) farm animals, and was discovered the next day, covered in blood in a glen.
His Lordship, an astute and experienced man, initially thought that his son was suffering from some variety of battle fatigue. The next full moon, however, demonstrated to the elder MacKenzie that something much worse was happening. Douglas realized it as well.
It drove him away. Douglas slipped out of the manor, to live life as an aimless,,,and nameless...wanderer, hoping that he could isolate himself during the full moon. Douglas was mostly successful, but along in his wanderings, at least once a year, and sometimes two or three times, he'd encounter a human. And leave them alive, spreading his curse.
The elder MacKenzie couldn't live with the knowledge and guilt of what his son had become and how he had failed to understand. As lycanathropy spread, by ones and twos, throughout Scotland, his Lordship cast about for a means of containing the threat. Casting about in the occult community of Scotland, he was referred to a wise woman who knew the means of enchanting a weapon so that it would be efficacious against the forces of Darkness. She worked with a silversmith to inlay silver runes on the frame of Douglas's service revolver, a .455 Webley, to make it a weapon that could use ordinary bullets to strike lethal blows against the unnatural.
The elder MacKenzie died in the late 1920's, seemingly of heart failure while out hunting.  Something was missing, when his body was found.  His son's service revolver.

Date of Setting

Early 1920's