StuG III Ausf. G (Sd.Kfz. 142/1; December 1942– April 1945, 7,720 produced, 173 converted from Pz.Kpfw. III chassis): The final and by far the most common of the StuG series. The Ausf. G used the hull of the Pz.Kpfw. III Ausf. M. Upper superstructure was widened: welded boxes on either sides were abandoned. This new superstructure design increased its height to 2160mm.
Backside wall of the fighting compartment got straightened, and ventilation fan on top of the superstructure was relocated to the back of fighting compartment. From March 1943, driver's periscope was abandoned.
From May 1943, side hull skirts (schurzen) were fitted to G models for added armor protection particularly against anti-tank rifles. Side skirts were retro-fitted to some Ausf. F/8 models, as they were be fitted to all front line StuGs and other tanks by June 1943 in preparation for the battle of Kursk. Mountings for side skirts proved inadequate, many were lost in the field. From March 1944, improved mounting was introduced, as a result side skirts are seen more often with late model Ausf G.
From May 1943, 80mm thick plates were used for frontal armor instead of two plates of 50mm+30mm. However, backlog of completed 50mm armors exited. For those, 30mm additional armors still had to be welded or bolted on, until October 1943.
Overall, Sturmgeschütz series assault guns proved very successful and served on all fronts as assault guns and tank destroyers. Although Tigers and Panthers have earned a greater notoriety, assault guns collectively destroyed more tanks.
Because of their low silhouette, StuG IIIs were easy to camouflage and a difficult target. Sturmgeschütz crews were considered to be the elite of the artillery units. Sturmgeschütz units held a very impressive record of tank kills—some 20,000 enemy tanks by the spring of 1944.