Shturmovaya samokhodnaya gaubitsa “Artshturm” SG-122 (Self-propelled Assault Howitzer “Artshturm”)
Many German Mark III and Mark IV tanks were captured and converted to light SUs. The Russians converted captured German Mark III tanks into the SU-76i at Zavod No. 38. More than 1,200 of the German chassis were rebuilt as fully armored self-propelled 76 mm guns and used as both tanks and SUs. The 1202th Mechanized Artillery Regiment was formed near Moscow on January 13, 1945, and equipped with 21 SU-76is. After enduring losses, the regiment received seven replacements, showing the continued availability of the type. The 438th Mechanized Artillery Regiment, formed in 1944, received rebuilt German assault guns. Later it received SU-85s made at Sverdlovsk. Use of the SU-76i in 1944 and early 1945 may have reflected a temporary shortage of SUs, as the number of regiments was rapidly expanded.
In May 1942, the design bureau under E. V. Sinilshikov proposed using captured German StuG III assault guns as the basis for a self-propelled gun armed with the Soviet M-30 122mm howitzer. In April 1942, Factory No. 592 was assigned the task of conducting these conversions. This factory had been located in Mytishchi until late October 1941, when it was evacuated to Ust-Katav in the Urals and amalgamated with the Kirov Locomotive Factory No. 13. The project was headed by A. Kashtanov and the vehicle was designated as the Shturmovaya samokhodnaya gaubitsa “Artshturm” SG-122 (Self-propelled Assault Howitzer “Artshturm”). Artshturm was the Russian name for the German assault guns (Artilleriya shturmovaya). The GKO ordered the conversion of 120 captured German vehicles and the first conversions were ready in September 1942. Improvements were designed with the cooperation of Uralmash in Sverdlovsk, including an improved gun mantlet. The conversion of the first 63 vehicles was planned for 1942. In the event only ten were completed in 1942, nine on StuG IIIs and one on a PzKpfw III chassis. On January 3, 1943, the GKO ordered the cessation of the program with instructions to complete remaining vehicles at the factory. Further conversion work was hampered by the decision to reorganize Factory No. 592 as the enlarged Factory No. 40 to produce the SU-76 after it was moved back to Mytishchi. In the event, 21 SG-122s were completed of which 12 were deployed with the 1435 SAP. All were knocked out by early 1943 and attempts to repair them were frustrated by a lack of spare parts.
This attempt to graft native technology onto foreign proved imperfect; the SG-122 was difficult to maintain in forward army depots because of lack of spares for the Panzer III chassis, whilst its performance was far below the rival UZTM design. These handicaps meant that although it was accepted for service in July 1942, the SG-122 was quickly withdrawn.
However, the desperate need for self- propelled artillery in the opening months of 1943 led Soviet designers to revive the idea of using over 300 Panzer III and StuG chassis which had been captured at Stalingrad. This move was intended as a stop-gap to make up for a shortage in self-propelled artillery when large numbers of the recently introduced SU-76s had to be temporarily withdrawn in order to iron out mechanical failures. Zavod Nr 38’s proposal was to take the basic design of the SG-122 and re-arm it with the 76.2mm (3in) ZiS-5 gun. Problems in installing the gun led to the adoption of the 76.2mm (3in) S-1 gun, which was specifically designed for self- propelled guns and which was easily mounted onto the front armour. After gruelling trials at Sverdlovsk, it was accepted for service as SU-76i (‘i’ denoting ‘inostrannaya’, or foreign) in March 1943, and they were deployed to front- line units from May onwards, just intime to see service with Colonel-General K. K. Rokossovsky’s Central Front and General N. F. Vatutin’s Voronezh Front at the Battle of Kursk in July that year.
Although available in only limited numbers, the SU-76i served widely in Soviet operations throughout the summer and winter of 1943, until the Chief of Armoured Forces, Marshal Va. N. Federenko, ordered all remaining vehicles to be transferred to training duties at the start of 1944. Despite its ad hoc nature, the vehicle seems to have proved popular with crews, who developed the dangerous habit of removing the bolted armour plate roof to increase their comfort! Modifications to the vehicle prevented this practice on later models.
A dedicated commander’s version of the SU-76i was also developed. A bulged extension was added on the right side of the superstructure that was topped by a captured German vision cupola. Of the 201 SU-76is that were converted, 20 were built in the SU-76i (komandirskiy) configuration.
The combat debut of the SU-76i was during the Kursk campaign in the summer of 1943. One SAP was deployed with the 13th Army on the Central Front and another SAP on the Voronezh Front. A third SAP was deployed to the Central Front during the later stage of the campaign. The 1901 SAP was committed to the fighting north of the Kursk sector on the Bryansk Front.
The only detailed account of the SU-76i at this time was recorded by the 1902 SAP that was raised in June 1943 under the command of LtCol Nikolai S. Grdzelishvili, and deployed with the 5th Guards Tank Army on the Voronezh Front in early August 1943. From 14 to 31 August, the regiment took part in five engagements and claimed two enemy tanks destroyed, along with nine guns, 12 machine guns, and 250 enemy troops. At the end of the month, the regimental commander reported that “all the vehicles are damaged from the previous fighting. Several of the vehicles were repaired multiple times and the conversions of the SU-76 on StuG III and PzKpfw III are worn out and in poor condition. The regiment was continually understaffed, but the training of the troops was satisfactory.” In September 1943, the 1902 SAP took part in 14 engagements during the Kremenchug campaign, including a series of skirmishes on 20-23 September 1943 in which six SU-76is knocked out three German tanks. Around seven replacement vehicles were received during the course of the month to make up for losses.
Besides deployment in the SPG regiments, SU-76is were used as tank substitutes when the 177th Tank Regiment, 64th Mechanized Brigade, 7th Mechanized Corps was formed in June 1943. This regiment had four companies with 11 SU-76is each, representing nearly a quarter of the total SU- 76i production. This unit saw combat against 1. Panzer-Armee in the autumn of 1943, during which one or more SU-76is were captured. One intriguing detail from a German intelligence report about this unit is that some of the SU-76is lacked a roof, apparently removed by the unit. At least one captured SU-76i was put back into use by Panzerjäger-Abteilung. 128 of 23. Panzer Division during the fighting around Krivoi Rog in the winter of 1943/44.
Conversion of the SU-76i concluded in November 1943 once production of the SU-76M had begun. Kashtanov made a proposal in August 1943 to continue the conversions using the D-5S 85mm gun, but this never proceeded due to a shortage of guns and the greater difficulty adapting the gun into such a small compartment. In 1944, the Main Directorate of the Armored and Mechanized Forces ordered the transfer of the SU-76i from frontline units to training units.