The SU-85 Assault Gun Development
The Russian T-34-76 Medium Tank and SU-76 Assault Gun had both demonstrated that a calibre 76mm main gun was not capable of penetrating the frontal armour of the German Tiger Tank.
Despite this, Russia was able to capture one and used it as a hard target to test which larger more capable main guns could defeat its frontal armour. The 85mm ZiS-S-53 Anti-Aircraft proved capable of this up to a range of 1000m and the model used was the D-5S-85.
To meet immediate operational requirements, the use of an existing assault gun chassis could speed up development and production, so the SU-122 chassis was selected.
Modifications of the SU-122 saw a reworking of the superstructure to accommodate the mounting of the D-55S-85 Main Gun and its manlet, but the chassis and running gear remained the same as the SU-122. A new telescopic sight was installed and later models fitted with a T-34 commanders cupola.
The SU-85 Assault Gun Service History
Designated the SU-85, it entered production in August 1943 at the Uralmash and Chelyabinsk tank factories and ended in September 1944 with roughly 2000 built.
It first saw combat in the summer of 1943 and was a great success within the Russian Army as it could successfully support the infantry in destroying German Tiger Tanks at range, eliminating the Germans advantage in superior armoured vehicles.
The introduction of the T-34-85 (fitted with a 85mm main gun) Medium Tank in 1944, which was being built at an astonishing speed and by the end of the war would total tens of thousands, took over the SU-85’s anti-tank role relegating it to an assault gun.
Despite this it remained in service until the end of World War 2. Its only real shortcomings was the lack of a Machine Gun mounted on the commanders cupola to protect the vehicle from a close in infantry attack, much like the German Elefant Tank Destroyer.
The SU-85 Assault Gun Spec’s
Armament: 85mm Main Gun (x48 rounds carried)
Armour: 54mm sloping steel (frontal)
Dimensions: Length 3m / Width 3m / Height 2.25m
Weight: 29.2 tonne
Engine: 500bhp V2 12 cylinder diesel
Top Road Speed: 47km/h
Operational Range: 400km