In any event, I don't believe it is for the Vickers. I believe the Vickers leather funnels all had a metal spout/nozzle that was affixed to the leather funnel. That leather spout/nozzle would get chewed up pretty quickly if inserted into the fill hole of a Vickers water jacket.
Paging @redroth . Redroth to the white courtesy phone please....
Since it was stated that there was a brass/copper tube inside the leather of the funnel tube,it does not seem out of the ordinary that with use the leather was prone to damage,especially during combat. Therefore,because there was likely to be haste in filling the water jacket,a bend in the brass/copper tube might have been thought to be a better modification on the later funnels and eliminate the leather covering.
A forum community dedicated to Browning 1919 A4 firearm owners and enthusiasts. Come join the discussion about performance, gunsmithing, restoration, troubleshooting, reviews, accessories, classifieds, and more!