(Fig. 5)

The bomb is painted a dull red and stencilled in black. The overall length is 12.95 inches, the maximum diameter 3.18 inches and the weight, filled and fuzed, is approximately 7.75 lb.

The construction of the bomb is similar to that of the 5 cm type shown in Pamphlet No. 4, Fig. 5, but the cartridge container is fitted with twelve vanes instead of eight and has four rows of perforations for the escape of pressure. Also, the guide band or parallel por-tion of the body has four grooves. The body is made of cast iron.

The bursting charge consists of approximately 1.1 lb. of T.N.T. and has a cavity below the fuze hole for reception of the steel container which holds the gaine.

The gaine has a cylindrical body of aluminium containing a 535-grain filling of P.E.T.N./ Wax (87.8/12.2 per cent) and a detonator assembly. This assembly, fitted in the head of the gaine, consists of a flanged detonator shell which fits into a cavity in the gaine filling and closes the head of the gaine. The detonator contains 7.6 grains of lead azide and lead styphnate (63.2/33.8 per cent) over 7.7 grains of P.E.T.N. The flanged mouth of the detonator is closed by an aluminium changed cup with five holes in its base. An aluminium washer between two paper discs and surrounted by a leather washer is fitted in the head of the gaine and secured by the turned in rim of the body. The approximate dimen-sions of the gaine are: length 3 inches, diameter 0.9 inches.

The fuze bears the same number as that used in the 5 cm bomb, i.e. Wgr.Z. 38.

The propellant charge consists of a primary cartridge, carrying its own means of ignition, and three secondary charges. The primary cartridge is placed in the cartridge container of the bomb, where it is secured by a screw in the container and a bulge formed in the rolled paper body of the cartridge. The augmenting charges are fitted round the cartridge container in front of the vanes.

The primary cartridge (Fig. 5) is of the 12 bore sporting type and consists of a rolled pa-per body and liner containing 152 grains of graphited flake propellant and fitted with the usual type of cartridge head which is considerably reinforced. The dimensions of the disc are 0.04 x 0.04 x 0.009 inch. The copper cup and wads at the front end are pressumably intended to hold the pressure momentarily and ensure better ignition of the augmenting charges.

The augmenting charges each consist off four-and-a-half rings of annular sheet propel-lant covered with cambric are provided with a radial slit for assembly round the cartridge container. The sheet propellant is 0.017 inch thick and the weight of each charge is 138 grains.