Sherman Firefly - Armament

Armament

The main armament of the Sherman Firefly was the Ordnance Quick Firing 17 pounder. Designed as the successor to the British QF 6-pounder, the 17 pounder was the most powerful British tank gun of the war, and one of the most powerful of any nationality, being able to penetrate more armour than the 8.8 cm KwK 36 fitted to the German Tiger I, or the Panther tank's 7.5 cm KwK 42. The Firefly 17 pounder was able to penetrate some 140 mm of armour at 500 m (550 yd) and 131 mm at 1,000 m (1,100 yd) using standard Armour Piercing, Capped, Ballistic Capped (APCBC) ammunition at a 30 degree angle. Armour Piercing, Discarding Sabot (APDS) ammunition could penetrate some 209 mm of armour at 500 m and 192 mm at 1,000 m at a 30 degree angle, which on paper could defeat the armour of almost every German armoured fighting vehicle at any likely range. However, early production APDS rounds lacked accuracy, and the 50 mm penetrator was less destructive after it had penetrated enemy tank armour than the 76.2 mm APCBC shell. In any case, APDS ammunition was rare until late 1944.

Despite the Firefly's superior antitank capabilities, the tank was regarded as inferior to the regular Sherman against soft targets such as enemy infantry, buildings and lightly armoured vehicles. As the war in Europe neared its close, the Allies found themselves encountering these more often than heavy German tanks. Allied tank units therefore typically refused to completely switch to Fireflies. A good HE shell only became available in late 1944 and even then was not as potent as the standard Sherman 75mm HE shell. Another problem was that the powerful blast from the 17 pounder gun kicked up large amounts of dirt as well as smoke, making it difficult for the gunner to observe the fall of the shell, forcing him to rely on the commander to observe it and to order corrections. Dirt and dust revealed the position of the tank, so Sherman Fireflies would have to move every few shots. The recoil and muzzle blast could be severely jarring to Firefly crews and the muzzle blast frequently caused night blindness as well. This was a common problem on any tank armed with a high velocity gun, including Panther and Tiger tanks. The cramped nature of the turret meant that loading the large 17 pounder shell was difficult, so Fireflies had a lower rate of fire compared to regular M4 Shermans. Since the Firefly was a stopgap, these problems were never eliminated, as the Firefly was to be retired with the introduction of the new British tank designs.

The Firefly's secondary armament was the standard .30 inch coaxial machine gun in the turret. The hull mounted machine gun had been removed to increase ammunition storage for the main gun. A top-mounted .50 cal machine gun was also attached, though many crews removed it due to its awkward mounting and position near the commander, which limited a full 360 degree view when unbuttoned in battle.

In 1945, some British Shermans were fitted with a rail on either side of the turret for two "60 lb" (27 kg) high explosive 3 inch rockets. These were used at the Rhine Crossing by the tanks of a single squadron of the 1st Coldstream Guards. These tanks, called "Sherman Tulips", were conventional Shermans and Fireflies. The rockets, accurate when fired from aircraft, were less accurate when fired from a tank as they were being fired from a stationary point and had little slipstream over the fins. Despite this, the RP-3 was effective when its 60 pound warhead hit the target.