Medium tank to manufacture a well-balanced medium tank in very large numbers - around 57,000 T-34s and 49,000 M4 Sherman tanks were built during the war period. During and after World War II, the roles of light tanks were gradually taken over by less-expensive armoured cars and specialised reconnaissance vehicles. Heavy tanks, having shown their limitations in combat, experienced a limited post-war arms race of progressively more heavily armed and armoured designs. With the rise of more sophisticated anti-tank missile weapons, to which heavy tanks had demonstrated high vulnerability, these too were eventually phased out. With advances in technology, aspects such as
History of the tank was considered to be up to 10 tons, the medium (produced by the British) was roughly between 10 and 25 tons, and the heavy was over 25 tons. For World War II, increased weights resulted in the light tank being over 20 tons, the medium over 30, and the heavy, developed toward the end of the war, over 60 tons. During the period between the world wars, the weights of the classifications varied generally within these extremes. The U.S. National Defense Act of 1920 placed the Tank Corps under the Infantry. The Act's stipulation that "hereafter all tank units shall