British Vickers Cover Pin Mk IV & Check Nut Mk. II

Original Item: The Vickers gun?s receiver has two top covers, one at the front which retains the feed block assembly and a longer one at the rear which carries the rear sight and provides access to the lock and other internal parts. These two top covers are hinged to each other and to the receiver with the PIN, JOINT, COVER, MK IV and the NUT, CHECK, MK II. 
See Ian Skennerton, S.A.I.S No. 8, .303 Vickers Medium Machine Gun, Plate D1, items 9 and 10.  These parts are very rarely available for Vickers owners.  IMA has a few sets.  The joint pin and check nut have been inspected to assure that they will thread together.