HANDBOOK OF ENEMY AMMUNITION |
PAMPHLET No. 10 |
GERMAN, ITALIAN AND JAPANESE AMMUNITION |
JAPANESE 25 MM. CARTRIDGE Q.F. H.E./T. |
(Fig. 33) |
This fixed Q.F. ammunition is fired by the Japanese 25 mm A.A./A.Tk. gun. The round corresponds roughly to the British Hispano or Oerlikon types. The complete round weighs 8 oz. 10 drs. and comprises the following parts:– |
Shell and filling. |
Cartridge case and propellant. |
Shell and Filling |
The streamlined shell is machined from steel bar and is coloured as indicated in Fig. 33. At the forward end it has a drilled cavity 1.89 inches in depth and 0.64 inch in diameter. This carries the bursting charge, and is threaded internally at the nose to receive the fuze. This cavity is coated with black enamel. At the base a tracer cavity 1.38 inches in depth and 0.47 inch in diameter is drilled. The cavity is closed by a rolled-in steel was-her. Two copper driving bands are fitted. The rearward narrow band is 0.23 inch and the forward broad band is 0.69 inch wide. The leading element of the forward band is sloped gradually toward the nose of the shell. |
The bursting charge, of total weight 5 drs., consists of 3 pellets of T.N.T./ Aluminium composition (61/39 approximately). The upper pellet is annular and surrounds the maga-zine of the fuze. The whole is covered by a cardboard washer. |
The tracing composition is of the following composition:– |
Magnesium |
16.5 per cent. |
Wax |
3.2 per cent. |
Barium oxalate |
13.5 per cent. |
Barium chloride |
10.6 per cent. |
Sodium nitrate |
24.1 per cent. |
Pressed over the top of the tracing composition is a priming layer of the following ap-proximately formula:– |
Magnesium |
16.5 per cent. |
Wax |
3.2 per cent. |
Barium oxide and peroxide |
55.8 per cent. |
Sodium nitrate |
24.1 per cent. |
The total weight of tracing and priming is 5.25 drs. The surface of the priming composi-tion has a deep conical indentation. The trace burns with an intense white light, the du-ration is, however, not known. |
Cartridge Case and Propellant |
The cartridge case is of brass and is of the rimless type. It is 6.4 inches in lenght and 1.67 inches in diameter at the base. It is heavily necked and is attached to the shell by rolling round the lower dirving band with the lip of the case in contact with the rear of the forward driving band. The markings on the base of the case are indicated in the dia-gram. The marking 8.6/17 indicated the date as June, 1942. |
The propellant consists of 3 oz. 10 drs. chopped tubular grains (approximately size 0.2 inch x 0.1 inch/0.02 inch) of the following composition:– |
Nitrocellulose (Nitrogen content not determined) | 92.9 per cent. |
Dinitrotoluene | 5.7 per cent. |
Diphenylamine | 1.1 per cent. |
Graphite | 0.3 per cent. |
Primer |
The primer is the 12 grain primer percussion Q.F. cartridge described on page 75. |
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