i too have a 40mm bofors barrel and 20mm vulcan the vulcan was used on the musket and dragoon posted in pistol area and the 40mm was to be a whitwirth at first and switched to a hotchkiss mtn gun ,but then alas i ran into the barrels being made with all correct dims and i nol longer want to mess the 40mm
i dont have prints but had scaled dwgs ill see if i can scrounge them up its been years .