The Tank, Cruiser, Comet I (A34) was a British cruiser tank that first saw use near the end of World War II. It was designed to provide greater anti-tank capability to Cromwell tank squadrons. It was armed with a 77mm HV, a derivative of the 17 pounder, with the result it was one of the few British tanks with the firepower to challenge late war German designs. As a development of the Cromwell it was an interim design before the Centurion tank.
Seeing post World War II combat during the Korean war, the Comet remained in British service until 1958. Comets sold to other countries continued in some cases to operate into the 70s.
When the Comet arrived in September 1944 the British had at last a British tank with decent armour, speed and a good gun, many regard it was the best British tank of the war and they are probably right. The Comet was extremely fast, reliable, was easy to drive and had excellent off road performance. The 77mm gun was a slightly less powerful than the 17pdr but was still capable of penetrating thick armour especially when firing APDS ammunition. Armour was decent for a 33 ton tank but clearly inferior to the mammoth German tanks of the period but better than that of tanks such as the Sherman or Cromwell.
The Comet was essentially an enlarged version of the Cromwell, in 1943 attempts were made to mount Vickers' new high velocity 75mm gun in a Cromwell but despite many months and plans to have the tank in production shortly it was found that the gun would not fit into the Cromwell after all. This 75mm weapon was then modified to fire 17 Pounder ammunition and was known as 77mm so that there would not be confusion over ammunition supplies. The High Velocity 77mm was extremely accurate, more so than the regular 17 Pounder and was mounted on the Comet tank.
It had been planned to have the first crews equipped and trained with the Comet by December 1944 but due to the German offensive the crews did not have time to train until the new year, the Comet tank ultimately arrived too late but it's high speed was put to good use in Germany, this high speed also allowed to Comet to power its way through rough terrain that other tanks could not.
Interestingly the Comet tank was equipped with a relatively large amount of Amour Piercing Discarding Sabot (APDS) ammunition with around 20% of the armour piercing type of ammunition produced for the Comet being APDS. Both the 17 Pounder and 77mm fired exactly the same projectiles but due to the different cartridge the 77mm had a lower muzzle velocity and thus lower penetration. The turret could also be transverse 360 degrees within 24 seconds.
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