British Cromwell Mk. IV One of the most successful tanks fielded by the British in WWII, the Cromwell compared favorably with tanks of similar weight such as the Sherman and Panzer IV. Most were armed with the 75mm Q.F. Mk.V/VA, which was based on the 6 Pdr. but chambered to fire American ammunition. This was a very good dual-purpose gun, able to destroy enemy anti-tank guns at long range, or penetrate the frontal armor of a Panzer IV at normal battle ranges. However it was less effective against German heavy tanks. The Cromwell first saw action during the Normandy campaign, where it was at a disadvantage as it could not use its superior speed and agility, but this changed after the fighting moved to open country. Cromwell tanks made some spectacular advances in their pursuit of the Germans across Northern France, Belgium and Holland. The Cromwell served again in Korea and was finally retired in the late 1950's.