Original Item: The Vickers grip assembly is retained on the receiver body by two specialized pins, or, more accurately, machine screws. The lower pin is called the Joint Pin Mk I, and has a wide slotted head at the left end of the receiver and a sharply rebated male thread at the other end. This assembly includes the joint pin nut, also a special design, using a spanner-type screwdriver to remove. The nut is held in place with a split pin (Cotter pin), not supplied. The Mk I pin is the standard pin, and there is a Mk II that is somewhat longer for use with the dial sight bracket.