.30 inch Armour Piercing
The first .30 inch armour piercing rounds made in Britain were those loaded by Royal Laboratory on contract for the U.S. forces, using American supplied cases and British projectiles.
WWI Contract Armour piercing
These rounds, loaded at the Royal Laboratory could have any contemporary U.S. military headstamp. The contract was for 11 million rounds.
The bullets were similar to the standard American M1918 AP round and had a CNCS envelope. The bullet weight was 152 grains and the core weighed 80 grains. Identification was by a green neck seal.
Right: RL loaded AP round. Note green neck seal.
Armour Piercing W Mark Iz
This round would have been the American .303 inch M1 AP round, but Britain did not import or use any of this during WW2. Despite not being approved or used it was never the less shown as obsolete in Lists of Changes in July 1948. This was probably a mistake in the general clearing up of records of wartime approvals that were no longer needed.
Armour Piercing W Mark Iz
"Cartridge S.A. Armour-piercing .30 inch W Mark IIz" was not shown as approved in Lists of Changes but is referenced in various Small Arms Ammunition Information sheets issued during the war. It is the American M2 Armour-piercing round.
The case was the standard American Boxer primed case. Early deliveries were from Remington Arms Co. on British contract and had the caps ringed and a green primer annulus. The headstamp included the date and the British code of ".300Z". Later deliveries had the simplified code of "RA 43" or similar.
The bullet was flat based with a gilding metal envelope and a single cannelure. The bullet weighed 167 grains with an 80 grain hardened steel core and a lead/antimony tip filler. The base of the bullet was sealed with a gilding metal base pad. Rounds supplied on British contract had a green bullet tip but later Lend-Lease rounds used the standard U.S. black tip.
Propellant was about 53 grains of nitrocellulose and observed velocity for U.S. M2 AP at 78 feet was 2,715 fps. British contract rounds were specified at 2,710 fps.
R.O.F. Hirwaun Armour Piercing
In 1941 R.O.F. Hirwaun was given an order for 50 million rounds of .30 inch armour-piercing ammunition. This order, along with others for tracer and incendiary ammunition was subsequently cancelled but small quantities of AP were actually made with an Hirwaun headstamp.
The case was Berdan primed and bore the unique headstamp "HN 1942 AP".
The bullet was essentially a copy of the American M2 but was slightly boat tailed. Like the M2 it had a gilding metal base pad.