T30 Heavy Tank

The Heavy Tank T30 was a World War II American tank project developed to counter new German tanks, such as Tiger I, Tiger II, and the Jagdtiger or Soviet heavy tanks, such as IS-1 or IS-2. The T30 was designed at the same time as the T29 Heavy Tank.

Early tanks

Plans for four pilot heavy tanks were put forward in 1944; two T29 with a 105 mm gun and two T30 with a 155 mm gun. The T30 pilot models were started in April 1945 and were delivered in 1947. Apart from modifications to fit the different engine, the chassis was the same as the T29. The 155 mm (6.1 in) gun fired two-piece (shell and charge) ammunition. The loader was assisted by a spring rammer. The T30 was fitted with one of the largest guns ever used on an American tank. The notably high, rounded edge, turret was needed to accommodate the standing loader and large gun mount. Even then the gun could only be loaded at limited elevations. It could carry a mixed assortment of 34 AP (Armored Piercing) or HE (high-explosive) rounds.

Heavy tank

A heavy tank was a subset of tank that provided equal or greater firepower as well as armor than tanks of lighter classes, at the cost of mobility and maneuverability and, particularly, expense.

The origins of the class date to World War I and the very first tanks; designed to operate in close concert with the infantry and facing both artillery and the first dedicated anti-tank guns, early tanks had to have enough armor to allow them to survive on no man's land. As lighter tanks were introduced, the larger designs became known as heavies. The same basic role remained into World War II, with the British referring to them as infantry tank indicating this close support role.

As tank combat became more common, especially tank-vs-tank, the heavies also became platforms to mount very powerful anti-tank guns, and the role of the heavies began to change. By the end of the war they were a primary class, used both for dealing with heavy fortifications as well as forcing its way through enemy tank formations. They were also known as breakthrough tanks, indicating their purpose of spearheading the attack. In spite of this, in practice they have been more useful in the defensive role than in the attack.