Fragmentation Mk II, Mk IIA1; also Fuze M204

Over-all length, inches

4.5

Diameter, inches

Color

Weight, pounds

Filling

Weight of filling, ounces

Fuze

Delay, seconds

4.0 to 5.0

Description: The Fragmentation Grenade Mk II has a serrated cast-iron body of fa-miliar "pineapple" design. The grooves run both horizontally and vertically to assist in the formation of uniform fragments of effective size.

This grenade is issued loaded and fuzed with Igniting Fuze M204. This Fuze M204 pro-duces no noise other than that of the impact of the striker on the primer, and emits no smoke or sparks during its burning. The fuze consists of a body, striker, safety lever, and safety pin. The body of the fuze is cylindrical in shape and is threaded for assembly to the grenade. It contains the primer, a delay element sufficient to give an average delay of 4.5 seconds, and a detonator of PETN. At the top of the body, one side is extended and slotted to form a point of fulcrum for the attachment of the safety lever. The striker is retained by the safety lever. The lever is hooked under the lip of the fuze body, ex-tends across the head of the fuze and over the striker, and curves downward in an arc that conforms to the shape of the grenade body. The lever is held in position for shipping and handling by a split safety pin which passes through the safety lever, through the fuze body, and over the striker to protrude on the other side, where the pin is spread so that a pull of between 20 and 30 pounds is required to withdraw it.

Operation: When the safety pin is withdrawn preparatory to throwing, the lever is held in place by the hand holding the grenade. When the grenade is thrown, the lever is released. The striker, driven by its spring, throws off the lever and rotates about its pi-vot to impinge on the primer. The primer ignites the delay element, which takes from 4.0 to 5.0 seconds to burn through to a relay element which flashes through a flash channel to ignite the detonator. Explosion of the PETN detonator, detonates the main charge of the grenade.

The grenade can be thrown about 35 yards. Effective fragmentation covers an area of 30-yard radius, but fragments may travel as far as 200 yards.

Earlier models: This grenade replaces an earlier model, the Mk IIA1, which was iden-tical to the Mk II except for the fuze and the filling, the Mk IIA1 being issued with the Fuze M10A3. The only external difference is that the safety lever fits over rather than under the lip of the fuze body. The Fragmentation Grenade Mk II is filled with ¾ ounce of E.C. powder.

Figure 222. Fragmentation Grenade Mk II with Fuze M204 in place
(At right is the Fuze M10A3, issued with an earlier model.)