The StuG III G is a German assault gun. StuG stands for Sturmgeschutz, literally "assault gun". Assault guns are similar to tanks and were common with German and Soviet forces; the StuG III is armed with the same type of weaponry as the Panzer IV, but lacks a turret.
The StuG III, like the Panzer IV, began the war with a low-velocity 75mm gun. After the invasion of the Soviet Union the decision was made to upgrade (again like the Panzer IV) to a high-velocity 75mm gun, the same as that on the Panzer IV. The result is a vehicle with similar offensive capabilities as the Panzer IV (except a lack of turret) at reduced production and maintenance costs. It is estimated that nearly 12,000 StuG III's were produced during the war.
The StuG III's 75mm armament gives it good performance against enemy medium armour. Unlike tank destroyers, assault guns are also equipped with high-explosive ammunition, making them useful against infantry, structures and other soft targets. However, because of its lack of turret, it has reduced tactical capability, especially on the offensive, as it must align its entire body towards a target.