I have copies of advertisements in my files from both Cogswell & Harrison and Parker-Hale, during the early 1950's, listing S&Ws custom converted to .22RF, etc. and also an ad by Klein's Sporting Goods, Chicago, for " S&Ws custom converted by finest English Gunsmiths and proofed by Birminham Proof House. Medium weight excellent condition famous S&W M&P revolvers with specially made new 6 inch barrels of finest steel. New Rear sight is adjustable. Patridge front sight. New checkered waknut grips. Original S&W frame, cylinder, trigger & trigger assembly. $39.98 plain or $44.98 completely custom polished and blued." So, Swissman, it sounds like your friend has one of these English conversions of a Victory Model that a later owner has modified the barrel for a screw on device of some type. Whether a silencer, launching device, or theatrical prop is your guess. As said above, trying to silence a revolver is an exercise in futility.