The British Royal Ordnance Quick-Firing 17pndr was a 76.2mm gun was used as an anti-tank gun on its own towed carriage. It was the most effective Allied anti-tank gun of the war. Its APDS round was capable of defeating all but the thickest armour on German tanks. It could penetrate 140mm of armour at 500m (550 yd) and 131mm at 1000m’s.
Though the Sherman had proven its worth in North Africa, it would be going up against German Panther and Tiger Tanks in the forth coming D-Day landings and its main gun just wasn’t up for the job of penetrating their frontal armour.
So it was finally accepted that the 17pndr would be retrofitted in to the Sherman after a number of problems of this had been solved.
The 17pndr travelled 40 inches back as it absorbed the recoil whilst it was fired. The Sherman turret did not have enough space to accommodate this recoil. So the recoil system was completely redesigned, by shortening the recoil cylinders and were placed on both sides of the gun to take advantage of the width of the Sherman’s turret rather than be hindered by its height.
The gun breech itself was also rotated 90 degrees to allow for loading from the left rather than from on top.
The radio which was mounted in the back of the turret in British tanks had to be moved. An armoured bustle was attached to the back of the turret to house the radio. Access was through a large hole cut through the back of the turret. The hull Machine Gun was removed to create more space for storage of the larger 17pndr’s rounds.
During the D-Day Landings the Sherman Firefly was the most capable tank of taking out the Panther and Tiger Tank through its frontal armour and were deployed as 1 Firefly amongst a tank troop.
The British Sherman Firefly Tank Spec’s
Number built: (conversion of M4A3 & M4A4) 2000
Weight: 30.1 tonnes
Dimensions: Length 5.89m / Width 2.64m / Height 2.7m
Crew: 4 (Commander, gunner, loader / radio-operator, driver)
Armour: 89mm Steel
Armament: 17pndr (76.2mm) Main Gun (77 rounds stored) and .50 (12.7mm) Browning M2 MG, Coaxial .30 (7.62mm) Browning M1919 MG
Engine: 425hp Chrysler Multibank petrol
Operational Range: 193km
Top Road Speed: 40 km/h