I don’t know the date of the Western contract for the UK. One of the problems is that the contract records are not detailed enough. The actual record in our National Archives is a very large hand written ledger with the contracts listed chronologically. Unfortunately it often does not detail who the contract was with.
For example, dated 4th July 1940 “For Smith & Wesson M/C carbines. 210 million ball from USA incl. 10 million for Admiralty. 40,000 proof”.
Another: Dated 26th March 1941 Contract DDS/21739 20 million 9mm from USA for Schmeisser gun." I am not saying this was the Western contract, just that there is no way of telling.
The Western ammo was certainly in the hands of troops by mid 1943 because it was causing problems in Sten and Lanchester guns. Apparently there were many cases where the round did not re-cock the gun. The Ordnance Board ordered a trial of 10,000 rounds and reported in Proc. No. 25,884. I do not have the exact date of that to hand as I do not have a copy here. However, in a subsequent minute, Proc. 26,318 of 26th January 1944 a further trial was held after Western had changed the cap thay were using.
The original Western cap was their No.452 and they changed over to their No.768 at Lot No.6068.
The later trial was fired with Lanchester guns and WCC lots 6068 and 6069 with WRA Lot 2 as the control ammunition. It was found that the WCC gave a velocity at 90 ft of 1178fps which was lower than normally obtained with WRA.
A large number of “failure to eject” stoppages occurred under conditions in which the WRA functioned normally. The conclusion was that WCC with 768 caps gave a lower general level of recoil and MV than the WRA ammunition. “The WCC ammunition with 768 caps cannot be relied upon to function the Lanchester machine carbine under service conditions and under conditions of high protrusion of striker heavy set back of the cap occurs”
The recommendation was that a further trial with 1000 rounds of lot 6069 be held to see if it was better, but in the meantime the WCC ammo with No.768 caps was not cleared for service use in Lanchesters.
There was a note to the minute that manufacture of 9mm ammunition by the Western Cartridge Company has ceased.
That is about all I can tell you about the WCC ammo in British service at the monment.