The grenade is thrown by hand or fired from a rifled discharger device with a 7.92 mm S.A. cartridge. When used as a hand grenade it is initiated by a friction pull igniter which is operated immediately before thrown, and gives a delay of 4.5 seconds. As a rifle gre-nade is initiated by a percussion fuze or by a self-destroying device which functions after a lapse of 11 seconds from the time of firing.

The grenade is cylindrical with an ogival head and a nose fuze. An engraved driving band is formed near the base. The overall length is 5.51 inches and the maximum diameter over the driving band is 1.22 inches. The diameter of the body is 1.18 inches. The weight of the complete grenade is 9 oz. The grenade is unpainted but rustproofed.

Body with H.E. bursting charge and detonator.

Friction igniter with delay pellet.

Gas check base with delay pellet.

Direct-action fuze.

The body is in the form of a steel tube 3.15 inches long and 1.18 inches in diameter, the wall being 0.08 inch thick. A diaphragm, formed near the base end is bored centrally and screwthreaded to receive the friction igniter which is inserted from the base. The body is screwthreaded internally at the front end to receive the fuze and at the rear to receive the gascheck base.

The bursting charge consists of 1.1 oz. of P.E.T.N./wax in a waxed card-board carton with a central cavity to receive the detonator with its container at the front end and the igniter delay pellet at the base end. A sorbo washer, under another washer, is positioned between the base of the bursting charge and the diaphragm formed in the body.

The detonator, is similar to the No. 8 type but is larger and is perforated at the base so that it can be initiated by flash from either end. The aluminium container carrying the de-tonator is crimped to retain the detonator and flanged for support by the bursting charge surrounding the cavity.

The friction igniter contains a pull-wire led through a perforated copper cap containing friction composition. The inner end of the wire is coiled to resist its passage through the composition, a loop being formed at its outer end, for the attachment of the cord. The cord is passed through the loop and the ends are threaded through holes in a flat light alloy ring and tied. The ring is carried in a recess in the front face of the gascheck base, where it is retained by a spring ring.

The delay pellet is screwed into the front end of the igniter and provides a delay of 4.5 seconds beween the initiation of the igniter and the detonator.

The gascheck base is engraved to engage rifling and screwthreaded externally for inser-tion in the base of the grenade. An annular recess in the front face accommodate the ring of the friction igniter and its spring-retaining ring. A central flash channel connects this recess with another below which contains the delay pellet. The base is recessed and screwthreaded to receive a screwed closing plug. The plug has a hole leading from its outer face to a cavity in its inner face below the delay pellet.

The delay pellet consists of a brass cup with a flash hole at its base and containing a composition which provides a delay of 6.5 seconds between its ignition by the propellant charge and the subsequent ignition of the friction composition in the igniter.

The fuze is of aluminium and has an ogival body with a hole at the nose through which the cylindrical striker protrudes. The body is screw-threaded for insertion in the grenade and has an internal circumferential recess below the striker to permit the expansion of the coiled spring in flight. The striker carries a needle aurrounded by a spiral spring which is held between the underside of the striker and a cup-shaped retainer. The retainer has a central hole for the needle and has a step formed near the front end around which a length of flat spring coiled. The coiled spring is retained by a cylindrical arming ferrule with an internal groove near its base. A stirrup spring is held the retainer and the deto-nator holder. The detonator holder is screwed into the base of the fuze and carries an igniferous detonator in a perforated screwed plug. The holder is secured in the fuze body by a set screw.

The steel cartridge is of the 7.92 mm S.A.A. type, crimped at the neck, and containing a 439-grain propellant charge of nitrocellulose flake.

On acceleration the arming ferrule in the fuze sets back over the stirrup spring which en-gages in its groove and retains it clear of the coiled spring. During this period the coiled spring is held by the set back of the striker, and propellant gases, entering the flash hole in the screwed closing plug at the base, ignite the delay pellet.

During flight the coiled spring is expanded into the annular recess in the body by centri-fugal force thus leaving the striker with its needle supported only by the striker spring.

On impact the striker is driven in and the needle pierces the igniferous detonator of the fuze. The flash from this detonator initiates the detonator in the grenade, which in turn brings above the detonation of the bursting charge.

In the event of the fuze failing to function the flash from the delay fitment in the base, after a period of 6.5 seconds enters the perforations in the copper cap of the friction ig-niter and ignites the friction composition. This in turn ignites the attached delay pellet, which, after a delay of 4.5 seconds, initates the detonator in the grenade by a flash through its base and brings about the detonation of the bursting charge.

The gascheck base is removed by unscrewing so that the ring attached to the cord of the friction igniter is accessible.

Immediately before throwing the cord is tugged by means of the ring. This result in the pull wire drawn through the friction composition and the induction of the flash which ig-nites the filling of the delay pellet. After a delay of 4.5 seconds the flash from the delay pellet enters the base of the detonator and thus brings about the detonation of the bursting charge.