7.62x54mm
In July 1916 the Russian Military representative in Britain, asked for a supply of 7.62 x 54mm ammunition. Since at this time there was spare capacity in the U.K. the Ministry of Munitions agreed to supply 52,000,000 rounds per month which was shortly afterwards increased to 78,000,0000 rounds per month. Later in 1916 there was a further spare capacity in the U.K. of 65 million rounds per month which was offered to Russia for 7.62 mm. Russia accepted this as it would allow the cancellation of U.S. contracts, a procedure which would save about £2,500,000 per annum (approximately $10 million at 1917 rates).
Thus by December 1916 a supply of 143 million per month had been arranged. In January 1917, the British War Office decision to suspend their demands on current .303 inch deliveries released a further capacity of 60 million rounds per month for conversion to 7.62mm, and thus the total amount of this calibre allocated to Russia reached 203 million per month.
Of course, at this stage very little ammunition had actually been produced as the U.K. factories were only beginning to set up facilities for this calibre
7.62mm Ball Mark I
"Cartridge S.A. Ball 7.62 mm (Mark I)" was approved to design I.D.W. 3402 in January 1917 but was not shown in Lists of Changes.
The case was rimmed of solid drawn brass and the cap was copper or brass with 0.6 grains of cap composition coated with varnish. The headstamp either included the calibre "7.62" or the mark numeral "I". It was made at most of the UK factories and details of the various headstamps are shown below.
Bullet was pointed and had an envelope of 80/20% cupronickel with a core of 98½ / 1½% lead antimony alloy.
The propellant charge was Dupont No.16 Military powder of such size, shape and weight as meets the pressure and velocity specification.
The velocity was 2,800 fps ± 50 fps at a distance of 90 feet from the muzzle.
The mean pressure was not to exceed 18 tsi and the pressure of a single round was not to exceed 21 tsi.
The mean figure of merit for accuracy of 20 rounds was not to exceed 9.5 inches at 600 yards when fired from a 7.62 mm rifle in a fixed rest.
Cover page of the specification document for 7.62x54mm ammunition.
Headstamps
As mentioned above, virtually every ammuntion factory in the UK manufactured 7.62x54mm Russian ammunition. The one exception was Kings Norton metals Co. who were busy engaged on .303 inch Air service ammunition.
L. to r. Government Cartridge Factory headstamps (GCF2 used R/|\L headstamp).
L. to r. Greenwodd & Batley impressed and raised headstamps
L. to r. Three versions of the Kynoch Cyrillic headstamp.
Eley headstamp
Birmingham Metals & Munitions headstamp