The propellant charge of this fixed Q.F. round is contained in a vicose rayon bag with an igniter sewn to the bottom. The propellant is a nitrocellulose powder and consists of a bundle of green, yellow, brown and grey-black tubes. The colour are due to the inclusion of dyestuffs and appear to bear no relation to composition but may be used for blending purposes. The nitrocellulose used has a nitrogen content of ?3.3 per cent and the stabi-lizer is diphenylamine. A small proportion of sodium sulphate is also included. The igniter composition contains nitrocellulose and nitrogylcerine with possibly a small proportion of polynitroglycerine and akardite.

The primer is initiated electrically and is of unusual design. The fuze head with a compo-sition consisting mainly of lead styphnate in a nitrocellulose sheath has a resistance of approximately 2.2 ohms and is in circuit with the insulated contact plug and, through the spring washer, the body of the primer. The gunpowder filling, consisting of a pellet and granular, has a total weight of 31 grains. The magazine is closed by an aluminium disc with disc of paper or varnished fabric.

Fig. 20 – German Electric Primer for 7.5 cm Q.F. Cartridge

The amatol 40/60 bursting charge is directly pressed into the shell; the weight of the fil-ling is 653 grams (1 lb. 7 oz.). The exploder cavity contains a smoke box and gaine.

The smoke box, weighing 32 grams (1 oz. 2 dr.) consists of a waxed paper carton con-taining a smoke pellet of the following composition: –

Red phosphorus

85 parts

Paraffin wax

13 parts

Aluminia

2 parts

The shell is coloured green, stencilled in black, and has a complete weight of 12 lb. 9 oz.

Fig. 21 – German 7.5 cm H.E. Shell

The gaine has a cylindrical body of steel with a flange formed at its front end to engage the fuze hole bush. The magazine filling, 33.8 grams of P.E.T.N./ Wax is in an aluminium container which rests on pressed paper discs in the bottom of the body. The container is closed at the front end by the flange formed on the aluminium body of the detonator. The detonator fits into the a cavity formed in the magazine filling and contains 0.38 grams of P.E.T.N. over which is positioned an aluminium cap containing 0.41 grams of lead azide/lead styphnate. Four perforations are formed in the front end of the cap. The detonator is closed by means of a disc of red paper and secured in the container by a leather washer over which the mouth of the container is turned.

Fig. 22 – German Gaine from 7.5 cm H.E. Shell

The fuze kl.A.Z. 23 is designed to function on graze or impact and is similar in construc-tion and action to the A.Z. 23 described in Pamphlet No. 1, Sec. 4.

Details of the A.P.C. and smoke shells for this equipment are included in this pamphlet.