During the Second World War, the Sherman tank was ubiquitous, serving with Allied armies in the deserts, jungles, forests, and steppes. But what the Sherman boasted in numbers, it lacked in firepower, as its gun generally was unable to best a heavy German tank in a one-on-one duel. The British rectified this problem just in time for D-Day, and the powerful new gun’s flash was so bright that the modified tank earned the nickname ‘Firefly.’

The Sherman Firefly featured a 17-pounder anti-tank gun, giving the British an effective weapon to counter German Panther and Tiger tanks. To combine the 17-pounder and the Sherman, both had to be modified. The gun received a new recoil system and a reconfigured breach; and the tank added an enlarged turret to accommodate the gun, but lost the hull gunner crewman. The Firefly surprised the Germans and proved vital for the Allied fight for Caen in the Battle for Normandy. It then aided the drive into Germany, often providing covering fire for other tanks. During the Battle of the Bulge, the up-gunned Fireflies helped blunt the German armored attack. The British built over 2,000 Fireflies and, although improvised stop-gap measures, they proved highly successful.