A./T. Hand Grenade No. 74 Mks I and II (Obsolete)

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Description: The Grenade No. 74 Mk II consists of a globular bakelite flask containing the explosive filling, which is primarily nitro-glycerine and nitro-cellulose, a bakelite hand-le containing the firing mechanism, and an adhesive-treated sock. During filling, an air space is left to allow for expansion of the explosive. The sock covers the flask and is very sticky. The handle threads directly into the flask. Within the handle is a sharp stri-ker and a striker spring. A safety lever fits under a nut on the head of the striker and down the handle to hold the striker up and the spring compressed. The top of the striker is spread to retain the nut. A safety pin passes through holes in projections on the safe-ty lever, through the handle, and under the striker. The flask is closed at the neck by an externally threaded safety plug into which the detonator assembly is inserted immedia-tely before use. The detonator assembly consists of a percussion cap, a 5-second delay, a detonator, and a C.E. pellet.

A light metal container, made in two hemispherical sections joined by a spring hinge, clamps over the sticky flask for protecion during handling and shipping. Before the grena-de is used, this cover must be removed by releasing the spring clip at the neck of the case. Several small rubber projections on the inside of the case separate it from the ad-hesive sock.

The detonator assembly is placed into the well in the flask. The handle is then scre-wed into the neck of the grenade and the casing removed. The handle must be grasped firmly with the hand over the safety lever before the safety pin withdrawn. After the safety pin is removed, the handle is released and the striker spring forces the striker down, throwing off the safety lever and striking the percussion cap.

This grenade has been designed for use against armored force vehicles. It is supposed to stick to the target, but will not adhere to a sloping surface, should it be wet muddy, or oily. Although it can be thrown for short distances, far better effect will be obtained if the grenade is placed directly on the target with enough force to break the flask.

The viscous explosive filling tends to run at moderate temperatures; thus storage temperatures must be kept low. The grenades are definitely subject to sympathetic de-tonation.

Operation: The Grenade No. 74 Mk I is similar to the Mk II in operation, but differs in several constructional details. The Mk I had a glass flask which proved to the too fragile and was replaced by bakelite in the Mk II. The Mk I was filled to capacity with explosive and consequently leaked if expansion took place. The handle was fastened to the body by a plastic retaining ring which gave too weak a joint. The blunt striker was a frequent cause of misfires. The Mk I and II also employ slightly different detonator assemblies.