Description
The Bomb Mk IV is hexagonal in shape, having a hollow magnesium-alloy body, and a cast iron nose, with the body cast to the nose in manufacture. A tin-plate tail, closed by a tail cover, is secured to the other end of the body by three drive-screws, which also hold a steel striker housing in position in the body.
At the tail end, the body is counterbored to accommodate an igniting mechanism consisting of a striker, located in the striker housing, and a steel plate seated at the bottom of the counterbore and containing a 1.7-grain detonator. One end of the striker is pointed, and the other end projects through a hole in the striker housing. The edge of this hole is chamfered to permit a thin brass cross, secured to the striker, to be bent and pulled through the hole when the bomb functions. This cross forms a striker support during transit and storage. Movement of the striker towards the detonator is, when the bomb is packed in its case, prevented by a spring-loaded safety plunger housed in a sleeve. Two vent holes, plugged by cork inserts, are provided in the tail end of the body and communicate with the space between the igniter mechanism and the bomb main filling. A strip of primed cambric is located in this space. The Mk IVE is identical to the Mk IV except for a black powder burster charge, just abaft the nose plug in the body cavity, which replaces a small quantity of the thermite filler.
These incendiaries are carried in the Small Bomb Container or in Cluster Projectiles.
The 4-lb. Mk V and VE are similar to the Mks IV and IVE, except for the following differences. The bomb is initiated by a cap and anvil being struck by the striker, the striker having a blunt point. The cap is supported by an aluminum plate, and the striker housing is made of aluminum. A different kind of pressed priming composition is used, which is more violent than the priming compositions used in the Bomb Mk IV, and causes some of the magnesium alloy to scatter when the bombs are ignited. This bomb is actually the US AN-M50.
The 4-lb X, with 2- and 4-minute delays, Mk II is similar in construction to the Mk IV, except that a CE exploder is contained in the steel nose; this exploder being initiated after delay of either two or four minutes. The nose is painted dull red, for 3 1/2 in., with two 1/2-in. black bands separated by a 1-in. bright red band painted on the nose. A second bright red band, 1/2 in. wide and 1/2 in. abaft the dull red coloring, indicates that the incendiary is of the explosive type.
No “E” marks are now produced. The small black powder charge was not lethal, but served only as a deterrent.
Functioning
No information about functioning.
See Also
British Bombs - Designation and Classification
Source(s)
OP 1665, British Explosive Ordnance (1946)
