The 7.92x57mm (BESA):
In 1939 the British army adopted the 7.92x57mm cartridge for use in the tank-mounted BESA machine gun.
This adoption was not done to make a switch away from the standard British .303" cartridge but the pressure of the war made it impossible to change the original Czech calibre in to a calibre used in the British army.
The 7.92 BESA cartridge was produced in the following variations:
Two marks of ball ammunition were approved for service, the MK Iz and MK IIz. The MK IIz had a slightly modified bullet, the boattail was a little longer. The mark numeral was included in the headstamp.The use of CNCS and GMCS envelopes were both authorised.
Ball rounds; headstamps: K39 Iz, PC 40 Iz (Greek contract), K5 43 IIz, K57 2z.
Two variations of AP rounds were developed; the W mk Iz and the W mk IIz. The AP round had a hard steel core and the same shape as the ball rounds.
AP round, headstamp; K43 WIIZ
A total of three tracer rounds were approved for service, the G mk I, the G mk II and the G mk III. The mk I was a bright ignition tracer. The G mk I was changed only a little and became the mk II.(other design of tracer mixer) The G mk III was a dark ignition tracer, tracing dark to 150 yards and bright to a minimum of 1100 yards.
Tracer rounds'headstamps: K41 GIZ, K2 44 GIIZ, K57 G3Z.
Two types of incendiary rounds were approved for service. The B mk Iz and the B mk IIz. the latter had a modified composition to avoid premature barrel explosions.
Incendiary rounds'headstamps: K43 BIZ, K44 BIIZ.
Two variations of proof rounds were used. For Identification the proof round was copperwashed and had a yellow primer annulus. The letter Q was added on the headstamp.
Proof round, headstamp: R^L 45 Q2
3 drill rounds, the mk I, mk II and mk III, were approved for service. To avoid confusion and accidents, all the drill round are marked with vertical flutes or drilled holes in the case.
from left to right: Drill mk I, drill mk II, drill mk 3 (+ sectioned version).
Two types of inspectors cartridges were used by British armourers, the U mk I and U mk II.
Inspection round, headstamp: P-H 44 U II
No blank rounds or grenade round were approved for service but some were used. Other rounds were produced by ICI for foreign governments.
from left to right: drill (soldered bullet), drill (3 rings), blank (green wood), blank. headstamps: typical headstamp for export