theoretically able to penetrate some of armour at and at using standard armour piercing, capped, ballistic capped (APCBC) ammunition. Armour piercing, discarding sabot (APDS) ammunition could penetrate some 256 mm of armour at 500 m and 233 mm at 1,000 m, which on paper could defeat the armour of almost every German armoured fighting vehicle at any likely range. However, war 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. APDS ammunition was rare until the post-war period. While the Sherman Firefly was capable of carrying 77 rounds of ammunition, design features of the tank meant only 23 rounds were easily and readily available when the tank was in action. Though the 17-pounder had superior anti-tank capabilities, it lacked an effective HE round and was thus inferior to the standard Sherman 75mm gun against soft targets, such as 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 for the gun only became available in late 1944, and even then was not as potent as the standard Sherman 75 mm 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 shot (and forcing him to rely on the commander to observe it and to order corrections) and revealing the position of the tank (forcing the Firefly to move every few shots). Furthermore, the recoil and muzzle blast could be severely jarring to Firefly crews, and the muzzle blast frequently caused night blindness. The latter was a problem common to any tank armed with a high velocity gun, including the Panther and Tiger I. The cramped turret meant that loading the large shell was difficult, so the Firefly had a slower rate of fire than a standard M4 Sherman. Since the Firefly was a stopgap, these problems were never eliminated, as it was supposed to be retired with the introduction of the new British tank designs such as the Comet and later Centurion. The Firefly's secondary armament was the standard 0.3 inch (7.62 mm) Browning M1919 machine gun coaxial