Early StuG IIIG models

The Ausf G was the last production series of the StuG. RoIling off the assembly-line in December 1942, the Ausf G was produced until the end of the war, with no major design changes. In 1942, the decision was made to use Pz Kpfw III Fgst for StuG production, since the Pz Kpfw III was being phased out and replaced by the Panther. In response to this request, 165 Pz Kpfw III Ausf M Fgst were used as chassis for StuG Ausf G, with production from February to November 1943. In 1944, 173 Pz Kpfw III, returned to the factory for overhaul, were converted to StuG Ausf G. 

 StuG III Ausf. G (Sd.Kfz. 142/1; December 1942– April 1945, ~8423 produced, 142 built on Panzer III Ausf. M chassis, 173 converted from Panzer III): The final and by far the most common of the StuG series. Upper superstructure was widened: welded boxes on either sides were abandoned. This new superstructure design increased its height to 2160 mm. 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. In February 1943 Alkett was joined by MIAG as second manufacturer. From May 1943, side hull spaced armour plates (Schürzen) were fitted to G models for added armour protection, particularly against Russian anti-tank rifles, but were also useful against hollow-charge ammunition. Side plates 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 the side plates proved inadequately strong as 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, 80 mm thick plates were used for frontal armour instead of two plates of 50 mm + 30 mm. However, a backlog of StuGs with completed 50 mm armour existed. For those, a 30 mm additional armour plate still had to be welded or bolted on, until October 1943.

A rotating cupola with periscopes was added for the commander for Ausf G. However, from September 1943, lack of ball bearings (resulting from USAAF bombing of Schweinfurt) forced cupolas to be welded on. Ball bearings were once again installed from August 1944. Shot deflectors for cupolas were first installed from October 1943 from one factory, to be installed on all StuGs from February 1944. Some vehicles without shot deflectors carried several track pieces wired around the cupola for added protection.

From December 1942, a square machine gun shield for the loader was installed, allowing an MG 34 to be factory installed on a StuG for the first time. F/8 models had machine gun shields retro-fitted from early 1943. The loader's machine gun shield was later replaced by rotating machine gun mount that could be operated by the loader inside the vehicle sighting through a periscope. On April 1944, 27 of them were being field tested on the Eastern front. Favourable reports led to installation of these "remote" machine gun mounts from the summer of 1944.

Later G versions from November 1943, were fitted with the Topfblende pot mantlet (often called Saukopf "Pig's head") gun mantlet without coaxial mount. This cast mantlet with organic shape was more effective at deflecting shots than the original boxy mantlet armour of varying thickness between 45 mm and 50 mm. Lack of large castings meant that the trapezoid-shape mantlet was also produced until the very end. A coaxial machine gun was added first to boxy mantlets from June 1944, and then to cast Topfblende from October 1944, in the middle of "Topfblende" mantlet production. With an addition of a coaxial, all StuGs carried two MG 34 machine guns from fall of 1944. Some previously completed StuGs with boxy mantlet had a coaxial machine gun hole drilled to retrofit a coaxial machine gun, while Topfblende produced from Nov. 1943 - Oct. 1944 without machine gun opening could not be tampered with. Also from Nov.1943, all-metal return rollers of a few different types were used due to lack of rubber supply. Zimmerit anti-magnetic coating to protect vehicles from magnetic mines were used from September 1943-September 1944 only.

Notice that on this gunner's side of the recoil shield there are two black objects and an associated electrical wire. The top one is a signal light and the lower a simple on/off switch. After the loader rams his round into the breech, he pushes his safety switch (on his side of the gun) and this light would glow to indicate to the gunner that the weapon was loaded, locked, and ready to fire. The wire hanging down from the on/off switch leads to an emergency back-up firing device, should the palm switch on the traverse wheel fail to electrically fire the gun.