text: Commonwealth The .30-06 (or "caliber .30") cartridge was adopted in 1940 during the beginnings of the Lend-Lease program in anticipation of using American weapons in front-line service. The British used American-made ammunition during the war, which was designated as cartridge S.A, .30 to avoid confusing it with their own .303 British service round. It was used after the war as belted machinegun ammunition by the Royal Armored Corps and was not declared obsolete until October, 1993. The "z" after the numeral indicates that it used a nitrocellulose propellant rather than cordite. Marks of ammunition were originally designated with Roman numerals (i.e., .303 Ball Mark VII), but were replaced with Arabic numerals by 1945 (i.e., .303 Ball MK 7).
  Cartridge S.A, .30 ball MK Iz: This was the War Ministry's designation for the 172-grain .30-06 Ball M1 round. It was not accepted for use in service, as the American military had already marked it as limited standard.
  Cartridge S.A, .30 ball MK IIz: This was the War Ministry's designation for the 150-grain .30-06 Ball M2 round. Lend-Lease ammo made for the British government had no mark designation and was headstamped .300z.
  Cartridge S.A, .30 ball MK 3z: This was the designation for an experimental round designed in 1945 for Royal Navy use that was based on the .30-06 ball M2. It was not adopted for service.
  Cartridge S.A, .30 ball MK 4z: This is a boat-tailed cartridge with a 150-grain full metal jacketed bullet. It is marked with a purple annulus. It was normally packed in 20-round cartons. However, Commonwealth countries that used the M1 Garand (like Pakistan) bundled it in 16-round cartons that contained two preloaded 8-round Mannlicher-style en-bloc clips.
  Cartridge S.A, .30 ball MK 5z: This was made under contract by Fabrique Nationale in the 1970s.