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In the mid 1920's Vickers designed a new high velocity .5 inch machine gun which they called the Class D and D*. Kynoch developed the new round for this weapon which was available in two bullet weights, 664 grains and 690 grains. The cartridges were known respectively as the Vickers .5 inch V/664 and V/.690.
These were very powerful rounds, the .5V/690 having a muzzle velocity of 3,041 feet per second compared to the .50 inch Browning velocity of 2,798 fps for the same bullet weight.
The gun and ammunition were tested at Woolwich during the 1930s and in June 1935 Kynoch supplied 10,000 rounds of .5V/690 ball and 10,000 rounds of tracer, followed by a further 10,000 rounds of .5V/664 ball and 10,000 rounds of tracer in April 1936.
Despite this, the .5 Vickers High Velocity was never approved for service. However, there is evidence that following the Dunkirk evacuation when every weapon was at a premium in Great Britain, a small number of Class D and D* guns were taken into service.
In 1940 Woolwich ordered 700 rounds of ball marked with a purple tip and 600 rounds of armour piercing with a green tip. This was obviously insufficient for any service use but may have been for a late trial of these weapons before issue.
Pamphlet No.11, Part 7, Small Arms Ammunition, 1945, gives details of the cartridge length compared to the service .5 inch Vickers and Browning rounds and lists the High Velocity rounds as experimental types in the ammunition tables.
Table from Pamphlet No.11 showing .5 inch Vickers High Velocity ammunition.
Interestingly, the charge weights shown of 20.5 grains and 21 grains are incorrect. They are apparently taken from the Kynoch ballistic tables which are in metric and these weights are in grams not grains. The actual charge weights in grains are 324 grains and 316 grains respectively.
The .5 inch High Velocity was not a success commercially. Small numbers were sold to the Imperial Japanese Navy Chile and Siam, the total exported being about 100 guns.
.5 inch V/664
Bullet weight of the .5 inch V/664 was 664 grains and the propellant charge was 316 grains of Nobel nitrocellulose powder.
Muzzle velocity was 3,035 feet per second.
The round was offered in Ball, Tracer, Armour-piercing and Armour-piercing Tracer. Proof and drill rounds were also made.
Two types of Ball bullet were offered, one with lead core and aluminium tip filler and the other with a mild steel core. It is believed that the mild steel core ball was identified by a purple bullet tip.
Identification of the other loads was either by coloured tip, case head stripe, annulus colour, code letter in the headstamp or a combination of these methods.
Left to Right:
Possibly early proof round with plain head, no annulus colour and purple stripe,
Armour-piercing with green annulus and "W" code in headstamp
Armour-piercing Tracer with green annulus, green over red bullet tip and headstamp code "AP T", a non standard code for British ammunition.
.5 inch V/690
Bullet weight of the .5 inch V/690 was 690 grains and the propellant charge was 324 grains of Nobel nitrocellulose powder.
Muzzle velocity was 3,041 feet per second.
All the comments above regarding the loadings available in the .5 inch V/664 apply equally to the .5 inch V/690.
Left to Right:
Tracer with red annulus, red tip and "G" code in headstamp.
Tracer with purple annulus, red tip and red case head stripe.
Ball with purple annulus and mild steel core.
Ball with purple annulus and lead core.
Incendiary (Smoke Tracer) with blue annulus, blue tip and "B" code in headstamp.
Below:
Left: Box label for .5 inch V/690 ball rounds dated February 1935
Right: Partial box label for .5 inch V/690 Smoke Tracer Incendiary rounds.
Chromed drill round for Vickers .5 inch V/690 with ball headstamp.
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