The tracer weighs 3 oz. 5 dr. and consists of a steel tubular body, steel cup shaped liner filled with tracer and priming compositions, steel disc and a celluloid closing disc. All steel components are rust proofed.

The body has an overall length of 1.41 inches and a maximum diameter of 1.02 inches. It is screwthreaded for insertion in the base of the projectile.

The grey coloured tracer composition weighs 157 grains and consists of barium nitrate 50.4 per cent, magnesium metal 31.1 per cent, sodium oxalate 8 per cent, strontium ni-trate 3.5 per cent, and resinous matter 7 per cent. The grey priming composition, with brown substance at one end weighs 37 grains and consists of  barium peroxide 76.5 per cent, magnesium metal 13.4 per cent, barium nitrate 4.6 per cent, and resinous matter 5.5 per cent. The tracer and priming composition are pressed into the liner in separate increments by a convex serrated drift be-fore being inserted in the body from the front.

The front of the body is clossed by turning its mouth over the chamfered periphery of the steel disc.

The rear of the body is closed by a thin yellow opaque celluloid disc let into an undercut recess.