(Fig. 35)

This primer is of the push-in-type and fitted in the 25 mm H.E./T. cartridge described in this pamphlet.

The primer body is of brass the base being 0.63 inch in diameter, and the length 0.67 inch. The body is slightly coned and is 0.49 inch in diameter at the top. It is unthreaded and is pressed into the primer boss. At the base it is drilled to provide a cap chamber, which is connected by a flash hole to a drilled magazine.

The copper cap is secured in the cap chamber by ring punching and contain 1.5 grs. de-tonating composition containing Mercury fulminate, potassium chlorate and antimony sul-phide. This is lacquered and covered with a tinfoil disc. The anvil is pressed into the top of this cap and is in contact with the detonating composition.

The magazine contains a pressed pellet of sulphurless gunpowder (potassium nitrate 85 per cent., charcoal 15 per cent.), and is covered by a laquered paper disc. The top of the flash hole is covered by a thin paper disc.

The cap is struck centrally crushing the detonating composition. Flash passing through the flash hole fires the gunpowder pellet and so the propellant charge.

Gas sealing is effected only by the expansion of the primer into the boss and the expan-sion of the cap in the cap chamber.

Fig. 35