Kinnear, James/Pasholok, Yuri SU-122 Self Propelled Assault Gun

Volume 4 of the "Red Machines" series.

The "Red Machines" book series is dedicated exclusively to the Red Army. Each volume contains detailed information on a vehicle family, much of it previously unknown in the West and illustrated with a large number of photos, most of them previously unpublished. Each book contains design drawings, sketches, colour plates and tables to document all development stages and production variants of the vehicle.

The SU-122 was the first self-propelled gun on the T-34 chassis to enter service with the Red Army. Originally designed to provide general close support to tanks and infantry, the SU-122 self-propelled gun also proved to be an effective tank destroyer despite its unusual armament. The 122 mm M-1938 (M-30S) howitzer, with its relatively low muzzle velocity and lack of special armour-piercing ammunition, compensated for this by the sheer weight of its projectile. However, it did not have the usual direct aiming viisation for tanks.

The SU-122 was assembled at Uraltransmashzavod (UZTM) in Sverdlovsk and combined the chassis of the T-34 medium tank with the only armament manufactured in the immediate vicinity at the time. This technical "marriage of convenience" from wartime utilised the available resources around relocated production facilities and proved to be very successful.

The development of the SU-122 was not entirely straightforward. The road to the SU-122 began with a series of turret-mounted tank destroyer designs based on the T-34, which did not progress beyond the project stage. The first "serial SU-122" was not even built on a Soviet chassis; the early 122-SG was a combination of the 122-mm M-30S howitzer and captured German StuG III and Pz.Kpfw. A small number of these conversions were delivered to the Red Army. The first indigenous design of the SG-122M based on the T-34 was intended to rearm T-34 armoured chassis damaged in combat, but this concept was dropped due to a lack of donor vehicles. The final variant, based on a newly built T-34 chassis, went into series production in December 1942 as the SU-35 and was later renamed the more familiar SU-122.

Although the SU-122 had a relatively short production time, it took part in most of the Red Army's combat operations in 1943-44. In the armoured artillery regiments, it was eventually replaced by the SU-85 tank destroyer, which was armed with an 85 mm gun. A very small number of SU-122s survived until the end of the war, with some being converted into armoured recovery vehicles and still in service years later. The later and better-known SU-85 and SU-100 armoured recovery vehicles thus owe their origins to the SU-122 and the "marriage of convenience" of 1942 in Sverdlovsk.