General

The various types of grenades used by the British are the anti-personnel, anti-tank, smoke, illuminating, and incendiary grenades. The individual grenades are generally hand thrown, rifle projected, or, in some cases, may be either hand thrown or rifle projected.

The British armed forces use anti-personnel grenades of both the offensive and the defensive types. Anti-tank grenades vary widely in principle and construction, and some-times incorporate a cavity charge to achieve greater penetration. Smoke grenades are of simple construction, and employ a white phosphorus charge, a burning smoke composit-ion, or a combination of the two to produce a heavy smoke screen. The rifle illuminating grenades consist of a basically similar series of grenades, which vary mainly as regards to filling. The single incenidary bomb in this section is not designated as a grenade, but is included because of its similarity and use.

Grenades are commonly initiated by firing mechanisms resembling the Bouchon type igniter, by all-ways action fuzes, or by integral striker assemblies. Special items are equipped for special initiation, such as the Grenade No. 76, which is ignited by reaction of its contents, when exposed to air, or the Grenade No. 75, which employs two separa-te chemical igniters to initiate its explosive train.

Designation

Grenades generally follow the usual British system of designation. They are idenitified by a "Number", corresponding to the U.S. Navy "Mark", and a Roman numeral "Mark", cor-responding to the U.S. Navy "Modification". Recent issues have the mark written in Arab-ic numerals.

Color and Markings

Grenade bodies are usually painted a solid color to indicate their use, as follows:

Anit-personnel

Anti-tank

Smoke

Illuminating

Incendiary

There are some departures from this listing, but it can be followed as a general rulle.

A red band, gerenally located near the top of an H.E. grenade, indicates that the grenade is filled. A ring of red crosses signifies that the filling is suitable for tropical sto-rage. The type of filling is identified by a colored band or bands around the center of the grenade body. The abbrivation of the filling is stencilled on this band.

Each grenade has the grenade designation stamped, cast, or stencilled on the body. In addition, the manufacturer's initial or symbol, and the month or year of manufacture are also shown. When the grenade is filled, the initials or symbol of the filling depot, the type of filling, date of filling, and filling lot number are stencilled on the grenade body.

In some cases, special markings may supplement or replace the standard markings.

Firing Mechanism

One type firing mechanism commonly used to initiate British grenades, is similar in principle and operations to the Bouchon type igniter used in U.S. grenades. These striker mechanisms employ a fly-off safety lever which is retained until use by a safety pin, a pivoted, spring-loaded striker retained by the safety lever, a percussion cap, a safety fuse delay, and a detonator. The detonator is a separate unit, which is inserted into the grenade beneath the striker mechanism shortly before using. The several striker mecha-nism which are in use differ from one another mainly in the shape of the body or safety lever, material of construction, or color of the safety lever.

The striker mechanism used in smoke grenades filled with a smoke composition do not have a detonator. The composition is ignited by a piece of primed cambric and priming composition, which are initiated by the delay fuse. W.P. filled grenades employ detona-tors to burst the container and expose the filling to the action of the air.

Many grenades employ specialized igniters and fuzes, which are peculiar to them.

Fuze No. 247

The Fuze No. 247 is an "all-ways" action fuze commonly used in a number of British grenades. The Fuze No. 247 Mk I has a body which is closed at one end by a closing cap and has a flash channel at the opposite end. A striker creep spring, cap pellet, and a lead ball are located inside the fuze body. The striker has a concave head, into which the ball fits, and a split striker point.

The creep spring separates the striker and cap pellet. A safety pin is inserted through the fuze body and the striker body, and has a length of fabric tape with a lead weight on the end fastened to its head. A plastic cap fits over the fuze body to hold the tape and weight in place.

The Fuze No. 247 Mk II differs from the Mk I in that it has a single point on the stri-ker, and uses a more powerful detonator, instead of a percussion cap, in the cap pellet. The No. III is the same as the No. II, except that the closing cap is cast in one piece with the body, and is closed instead by a plug in its base. Different lengths of tape are used to change the arming times of the fuze.

The Fuzes Mk I and Mk II are obsolete and will not be used for future issues.

The Fuze No. 247 is very sensitive when armed, and should be handled accordingly if encountered in this condition.