The SU-152 Assault Gun had proved a great success for the Russian Army in 1943 thanks to the ML-20S main gun. However being based and produced on a KV tank series chassis, Russian tank production was swapping to the more capable IS tank series (Joseph Stalin or Iosif Stalin tank) in 1943.
With the lack of KV chassis, the SU-152 design was modified to be built on an IS tank chassis (aka IS-1). Designated the ISU-152, it retained the popular ML-20S 152mm main gun, had lower suspension and a higher less sloped superstructure as the IS hull wasn’t as deep as that of the KV series and increased thickness to its frontal armour.
Development began in July 1943 at the Design Bureau of Factory No. 100 with the first prototype completed several weeks later ready for trials. The second improved prototype was completed in October designated Object 241.
It successfully passed factory and state trials and entered production at the Chelyabinsk Kirovsk Plant in December 1943. Over 4600 were built.
The ISU-152 Assault Gun Spec’s
Armament: 152mm Main Gun (x20 rounds stored), x1 12.7mm DShK MG
Armour: Frontal 75mm thick steel
Dimensions: Length 8.95m / Width 3.25m / Height 2.45m
Weight: 45.35 tonne
Engine: 600hp 12-cylinder diesel model V-2K
Top Road Speed: 43 km/h
Operational Range: 330 km
A trialled prototype, the design focused on the anti-tank role. It used the 152.4mm BL-8 (БЛ-8) long barrel gun, which was a staggering 8 meters long. Unlike the ML-20S, the BL-8 had an armoured piercing round and could defeat over 200mm of steel armour at 2000m.
Aka the Object 246, it was developed in 1944 but didn’t enter production.
The first post-war upgraded variant, development started in 1956. The upgrades focused on increasing the internal ammunition storage from 20 to 30 rounds carried, increased fuel capacity, replacement of the engine with that used on the new T-54 medium tank, additional fuel capacity, commanders cupola and sighting equipment.
The gun had a maximum range of 13km’s and the additional fuel capacity increased the operational range by 500km.
Development started in 1959. It had the same upgrades as the K variant above, but included additional armour over the upper section of the gun mantlet and night vision sights.