British Bomb, 40 lb GP, Mk 1, Mk 2, Mk 3, Mk 4
The bomb body is made of cast steel. The open hose end is threaded internally to receive an exploder container, which is screwed and cemented in position and locked by a set-screw. The rear end of the bomb is closed and reduced in diameter to form a spigot. A boss on the spigot is drilled and tapped to receive the forward threaded end of a tail rod. The exploder container is in the form of a tube closed at one end, the open end of which is threaded internally to take the pistol.
A cylindrical strut is attached to a tail cone by four fins. The tail unit is secured to the body by a tail rod which extends axially through the tail cone. The forward end of the rod, which screws into the central boss on the spigot at the rear of the bomb body, is locked by a spring washer and a lock-nut. The rear end of tail cone is fitted with an internally threaded flanged adapter, which screws on the threaded rear end of tail rod, correctly locating the tail cone on the bomb body. The tail is locked in position by a spring washer and lock-nut screwed against the adapter.
This bomb is usually used as a fragmentation bomb, being almost identical to the 20-lb. fragmentation bomb except for size.
The exploder system of the Bomb Mk IV was changed to use only CE pellets, and a special retarder tail was incorporated.