I’m a member of Canadian Military Photos Lost & Found group on Facebook, there is a photo of a RCASC dispatch rider in Holland ,,1944 wearing a Pattern 37 holster , with a large revolver, as the butt is sticking out , i mentioned that it looked like it might be a Smith & Wesson 1917 revolver , as Canada did acquire these revolvers in WW1 , the fellow who posted the photo of his father wearing the holster said it was. Colt 1917 using .45 acp ammo with the half moon clips , I always thought any revolvers , Smith & Wesson or Colt revolvers that Canada or British purchased were chambered in the .455 Webley cartridge, and only US troops used revolvers with the half moon clips