Basic Information
The assault gun was a class of armoured fighting vehicle developed in Germany during the late 1930s. Developing this class of vehicle was intended to resolve the question of whether the tank should be retained in its original role of infantry support or should be allowed to develop into a new weapon of penetration and exploitation. The German army of the time favoured the latter course and so the sturmgeshutz (roughly "assault gun") was developed to fulfil the infantry support role. The first series produced version was the StuG III, based on a turretless chassis of the Model III medium tank (Panzer III) with a casement mounted, low velocity 75mm cannon (noting that standard tank guns of the period were 35-50mm high velocity weapons). The new vehicle was cheaper to produce than the equivalent tank, armed with an artillery grade weapon and could afford better armour on a lower profiled hull. Although designed for direct fire infantry support, the StuG was also capable of indirect fire as a form of self-propelled gun. Early versions fought in the battle of France and were subsequently ubiquitous within the German forces until the end of WW2, becoming the most numerous model of AFV in their arsenal. Later versions carried larger weapons - including 105mm guns (for improved explosive performance) and high velocity 75mm cannon (for improved anti-tank capacity), the latter causing them to blend into the ranks of the tank destroyers.
Surprisingly few other nations developed assault guns - the Soviets developed a variety of models, which also blurred the assault gun/tank destroyer line at times, and Italy was the other main adopter - with several models of semovente ("self propelled") deployed, although a combination of factors made their roles somewhat ambiguous. The Japanese brought at least one model into limited production, whilst the British avoided the idea altogether and US "Assault Guns" all appear to have been tanks re-armed for improved HE performance.
After WW2, assault guns fell out of fashion (besides the consumption of war salvage and surplus in "the savage wars of peace") - the development of the Main Battle Tank concept changed idea of tank design and deployment and that, coupled with improvements in infantry firepower and postwar cuts to the size of AFV parks meant that this, less capable, vehicle concept was slowly phased out. If there is every a requirement for mass produced infantry support AFV again, and IFVs are not up the task, it may yet be revisited.
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