(Fig. 13)

The cartridge is used with the H.E. bomb (5 cm Wgr. 36) described in Pamphlet No. 4 and is identified by the marking "5 cm 39" at the base. The base is lacquered green to indica-te the full charge. A similar cartridge with a reduced charge, the "5 cm Wgr.Patr. 38 (gr.Ldg.)" has a red base.

The cartridge is used without augmenting cartridges and is of the usual primary type of mortars. The rolled paper body is green and the typical 28 bore sporting cartridge base is brass plated. The dimensions are shown on the drawing.

The rolled paper body is lacqured externally and is fitted with a lining tube also of rolled paper. The body is closed at the mouth by a cardboard wad which is held by the rim being turned inwards. At the base the body is strengthened by a steel liner in the form of a cup fitting externally over the end. The steel liner is covered by a copper liner which extends further up the body and is in turn covered by as brass-coated copper shell which forms the base. A wad of rolled back paper holds the cap chamber in the body within the metal liners.

The cap chamber is of steel with a coating of copper and contains a brass cap in its lower part. The cap contains a brass anvil and a 0.73 grain filling consisting of:– 35 per cent of lead styphnate, 4 per cent of tetrazene, 43 per cent of barium nitrate, 6 per cent of antimony sulphide and 12 per cent of calcium silicide. The cap rests on a soft copper foil disc which closes the base of the cap chamber. The base is lacquered green.

The propellant charge of nitrocellulose powder consists of a priming charge of cylindrical grains in the lower part of the body and a main charge of a square flake in the upper part. The two charges are separated by a paper or plastic film cup.

The priming charge has a nominal weight of 1 gram and the propellant is designated "Nz. Man.N.P. (1,5 x 1,5) f. Wgr." In the cartridge examined the charge weighed 15.7 grains. The propellant in the form of pale grey-green, porous chopped cords, with graphite in-corporated, has the following composition:– Nitrocellulose plus graphite 95.3 per cent, diphenylamine 1 per cent, potassium sulphate 1.1 per cent and included 2.6 per cent of volatile matter. The nitrogen content of the nitrocellulose is 13.1 per cent.

The main charge has a nominal weight of 3 grams and the propellant is designated "Nz. M.W.Bl.P. (2 x 2 x 0,45)". In the cartridge examined, the charge weighed 43.3 grains. The square flake propellant, lightly coated with graphite, has the following composition:– Nitrocellulose (nitrogen content 13 per cent) 98.1 per cent, diphenylamine 0.6 per cent and included 1.3 per cent of volatile matter.

Both propellants burn at a faster rate than of Ballistite B.16 and the cartridge should, thereforve, be efficient under wet weather conditions.

Fig. 13