The commander's version of the SU-76I self-propelled gun, equipped with a turret from a PzKpfw III tank, in the courtyard of factory # 37. Sverdlovsk, July 1943
The first experiments on re-equipping captured self-propelled guns with domestic guns were carried out at Moscow enterprises in late 1941 - early 1942. According to the memoirs of A. Klubnev, at the beginning of March 1942, six StuG III repaired at Moscow factories arrived in the 33rd Army, where he commanded a platoon of T-60 tanks. Three of them had a standard short-barreled gun, and three "were armed with cannons from the early thirty-four."
P. Min'kov, who also fought in the 33rd Army, told about the same vehicle, "armed with a KB gun" and knocked out by the Germans near Medyn in the spring of 1942. However, so far it has not been possible to find any documentary evidence of such alteration, nor photographs of such machines. We can only assume that such a rearmament was carried out on a single ACS.
More active work in this area began in April 1942, when the director of plant No. 592 of the People's Commissariat of Armaments (NKV) received a letter with the following content:
“Secret.
To the head of the repair department of ABTU KA, brigade engineer Sosenkov.
Copy: Director of Plant No. 592 Pankratov D. F.
In accordance with the decision taken by the Deputy. People's Commissar of Defense of the USSR, Lieutenant General of Tank Forces, Comrade Fedorenko, on the rearmament of captured "artillery attacks" with 122-mm howitzers mod. 1938 at the plant number 592 I ask you to give the necessary order for the repair and delivery of four captured "artillery attacks" to the plant number 592. To speed up all the work, the first repaired "artillery attack" must be delivered to the plant by 25 April. April 13, 1942 Chairman of the Technical Council, member of the NKV Collegium E. Satel (signature)"
It should be noted here that most of the equipment and workers of the plant No. 592 (the plant was located in Mytishchi near Moscow, now it is the Mytishchi machine-building plant) was evacuated in October – November 1941. By February 1942, the enterprise had only about 2000 workers and 278 machines, of which 107 required major overhaul. The main products of the plant at that time were the production of bodies for hand grenades, aerial bombs, casting of base plates for mortars and the construction of anti-aircraft armored trains.
Side projection SG-122
At the present time, it was not possible to determine the exact date of the start of design work on the 122-mm self-propelled howitzer, but the surviving copies of the drawings indicate April 1942. The project, carried out by the design team led by A. Kashtanov, was quite simple. The German StuG III assault gun with a conning tower extended upwards was used as a base for the new vehicle. Such an increase in the cabin made it possible to install a 122 mm M-30 howitzer in the fighting compartment. The new self-propelled gun was named "Artillery attack self-propelled howitzer SG-122", or in abbreviated form SG-122A.
According to the available description of the prototype, the SG-122A was converted from the StuG III assault gun. The conning tower of the assault gun with the roof removed was somewhat cut in height. On the remaining belt, a simple prismatic box of 45-mm (forehead) and 35-25-mm (sides and stern) armor plates was welded on. For the required strength of the horizontal joint, it was reinforced from the outside and from the inside with overlays with a thickness of about 6–8 mm.
Inside the fighting compartment, in place of the 75-mm StuK 37 gun, a new M-30 howitzer machine, made in the German style, was mounted. The main ammunition load of the howitzer was placed on the sides of the self-propelled guns, and several shells of "operational use" - at the bottom behind the howitzer machine.
The crew of the SG-122 (A) consisted of five people: a driver-mechanic (who took a place on the left-in front of the conning tower); the commander of the self-propelled guns, he is also the gunner horizontally (located behind the driver, left side forward); behind him, also sideways in the direction of the car, was the first loader (he is also a radio operator); opposite the commander of the self-propelled guns, with the right shoulder along the vehicle, the gunner was located vertically (the M-30 howitzer had separate aiming); behind him, too, with his right shoulder forward, was the second loader.
For the entry and exit of the crew, there were two hatches in the car. The main one was located in the stern of the wheelhouse, and the reserve one was located in the inclined part of the frontal armor of the wheelhouse in front of the gunner vertically. For communication, a standard German radio station was left in the car.
Due to the lack of the necessary equipment, materials and a lack of personnel, the first sample of the howitzer was tested by mileage (480 kilometers) and firing (66 shots) only in September 1942. The tests confirmed the high combat capabilities of the SG-122A, however, they also revealed a large number of shortcomings: insufficient maneuverability on soft ground and a large load on the front road wheels, a large load on the ACS commander, a small cruising range, the impossibility of firing from personal weapons through the side embrasures. for their unfortunate location, rapid gas contamination of the fighting compartment due to the lack of a fan.
One of the few surviving images of the SG-122
The plant was ordered to manufacture a new version of the self-propelled howitzer, taking into account the elimination of the noted shortcomings. It was also recommended to develop a version of the conning tower to install it on the PzKpfw III tank, which had more running gears than assault guns.
After revising the project, plant No. 592 manufactured two improved versions of the SG-122, differing in the type of chassis used (assault gun and PzKpfw III tank), which had a number of differences from the prototype.
So, the deckhouse was welded from thinner 35-mm (forehead) and 25-mm (sides and stern) sheets. This made it possible to slightly reduce the weight of the vehicle and somewhat improve its cross-country ability. The "staff schedule" of the SG-122 crew was changed: now the vertical gunner became the commander of the ACS, who received his own hatch in the wheelhouse roof. In addition, to review the terrain, the commander received an artillery reconnaissance periscope, which could be advanced in a special glass.
The side embrasures for firing personal weapons were redesigned. Now it was possible to fire through them not only from the "revolver", but even from the TT and PPSh, since the diameter of the embrasure hole was much larger than the previous ones.
The gun mount was lightened, and to simplify loading, the gun was equipped with a folding tray. An electric exhaust fan was installed in the roof of the wheelhouse.
To increase the power reserve, box-shaped fuel tanks from BT and T-34 tanks were placed on the fenders of the self-propelled guns, while the transportable spare parts and trench tools were somewhat reduced.
Specially for the order of the plant № 592 for the SG-122 "improved" Uralmashzavod (UZTM) developed and cast an armored mask of the gun, which was more adapted for serial production than the previous one, and also better protected from bullets and shrapnel. This made it possible to do without bulky side shields, which made it difficult to maintain the machine and increase the load on the front road wheels.
According to the report of the plant No. 592, in 1942, a total of ten SG-122s were manufactured (with a plan for a year of 63 vehicles), one on the T-3 chassis, and the rest on the StuG III chassis. By November 15, 1942, there were five SG-122s at the artillery range near Sverdlovsk. One of the two "improved" SG-122 - on the chassis of the PzKpfw III tank - was delivered to the Gorokhovets proving ground on December 5 for comparative State tests with the U-35 (future SU-122) designed by Uralmashzavod.
A prototype SU-76I being tested in the Sverdlovsk region, March 1943. There is no shield on the gun's mask
The prototype SU-76I moves on virgin snow. Sverdlovsk area, March 1943
Prototype SU-76I. The shape of the cast armored mask is clearly visible. Sverdlovsk area, March 1943
Experienced SU-76I. Sverdlovsk area, March 1943
Experienced SU-76I with open aft hatches. Sverdlovsk area, March 1943
Interior view of the SU-76I wheelhouse through the rear hatch on the port side. The ammo rack, the breech of the gun, the gunner's and driver's seats are visible.
Interior view of the SU-76I wheelhouse through the rear hatch on the starboard side. The ammo rack, the cannon breech and the commander's seat are visible.
Serial sample of SU-76I. This car was in the museum in Kubinka and was scrapped in 1968.
Serial version of the SU-76I. The vehicle already has a shield on the gun mantlet and additional fuel tanks at the stern.
The order for 122-mm self-propelled howitzers to plant No. 592, which was supposed to be in 1943, was canceled, and on February 11, 1943, all manufactured SG-122s stored on the territory of the plant, by order of the NKV were transferred to the head of the armored department for the formation of training tank-self-propelled divisions.
Another SPG on a trophy chassis - SU-76I - became more widespread. The history of its appearance is as follows.
In January – February 1943, mass transmission accidents began to occur, which were adopted by the SU-76 (SU-12). The cause of these accidents was the parallel installation of two twin motors running on a common shaft, which led to the occurrence of resonant torsional vibrations. The defect was considered structural, and it took a long time to eliminate it. Thus, in February 1943, most of the SU-76 (SU-12) required repairs and could not be used for combat. The Red Army was deprived of the most needed 76-mm self-propelled divisional guns.
It was urgently necessary to find a temporary solution for the production of self-propelled 76-mm guns for the summer campaign of 1943. And here Kashtanov's proposal to re-equip the SG-122 with a 76-mm divisional gun came in handy. In addition, according to reports from trophy services, after the end of the Battle of Stalingrad, more than 300 German tanks and self-propelled guns were delivered to the repair enterprises of the People's Commissariat of the Tank Industry (NKTP) and NKV. The decision to prepare for serial production of the 76-mm assault self-propelled gun on a trophy chassis was made on February 3, 1943.
The design team of Kashtanov was transferred to Sverdlovsk, to the territory of the evacuated plant No. 37, and by order of the NKTP was transformed into a design bureau and began to refine the SG-122 project. Time was short, as the prototype SPG was supposed to be ready by March 1. Therefore, the drawings of many units were already made "retroactively", measuring the prototype.
Unlike previously manufactured self-propelled howitzers, the wheelhouse in the new self-propelled gun received inclined sides, which increased their strength. Initially, it was planned to install a 2-mm ZIS-3 cannon in the fighting compartment of the ACS 76 on a machine fixed to the floor, but such an installation did not provide reliable protection of the gun embrasure from bullets and shrapnel, since slots were invariably formed in the shield when lifting and turning the gun.
But this problem was resolved by installing a special self-propelled 76, 2-mm S-1 gun instead of the 76-mm divisional gun. This gun was designed on the basis of the F-34 tank gun and was very cheap. It was developed for light experimental self-propelled guns of the GAZ plant. The new gun differed from the F-34 in the presence of a gimbal, which made it possible to install it directly into the frontal sheet of the hull and free up the useful volume in the fighting compartment.
On February 15, 1943, the head of the Department of the Chief Designer of the NKTP S. Ginzburg reported to the People's Commissar that "… plant No. 37 began manufacturing a prototype of the 76-mm S-1 self-propelled assault gun …" …
The tests took place in the vicinity of Sverdlovsk by driving along roads and virgin snow with a locked and unlocked gun. Despite the harsh weather conditions (thaw during the day, and frost at night, reaching 35 degrees), the car showed itself well, and on March 20, 1943.the vehicle was recommended for adoption under the designation SU S-1, SU-76 (S-1) or SU-76I (Foreign).
The first five serial self-propelled guns on April 3, 1943 were sent to the training self-propelled artillery regiment, stationed in the suburbs of Sverdlovsk. During the month of service, the vehicles “dashed off” from 500 to 720 km and assisted in the training of more than 100 future self-propelled gunners. Reviews of the car were good, and only the difficulty of starting the engine in the cold (for a quick start, you often had to pour hot gasoline into the carburetors) was noted by all technicians as a "disadvantage of the first importance."
In the meantime, according to the revised drawings, the plant began manufacturing a front-line series of 20 self-propelled guns, which for the most part also ended up in training units. Only from May 1943 SU-76 (S-1) began to enter the troops.
The first self-propelled guns had a rather "Spartan" look. Their conning tower was welded from armor plates with a thickness of 35 mm in the frontal part and 25 mm or 15 mm in the sides and stern. The roof of the wheelhouse was originally cut out of a single sheet and bolted. This facilitated access to the fighting compartment of the ACS for repairs, but after the battles in the summer of 1943, the roof on many ACSs was dismantled to improve habitability.
Since at the beginning of 1943 radio stations were in short supply, they were installed on every third vehicle, especially since most of the self-propelled guns entered training units. But already from the middle of May, almost every SU-76I (S-1) was supplied with radio stations of the 9-R type.
At the end of July 1943, according to the experience of using the SU-76I on the Kursk Bulge, an "armored baffle" was installed on the swinging armor of the gun, the purpose of which was to prevent the gun from jamming by small fragments and bullets. At the same time, to increase the range, self-propelled guns began to be equipped with two external gas tanks, which were installed along the stern on easily resettable brackets.
Initially, captured PzKpfw III were used as command vehicles in self-propelled artillery regiments (SAP) armed with SU-76I. In August, it was decided to manufacture also special commander ACS, which were equipped with a commander's cupola from the PzKpfw III and a radio station of increased power with a reduced ammunition load.
The last SU-76Is left the plant at the end of November 1943. By this time, the shortcomings of the domestic SU-76s had been eliminated, and they were shipped to the front in the required quantity by two enterprises of the NKTP (plant No. 38 in Kirov and GAZ in Gorky). Soviet self-propelled guns were cheaper and lighter in comparison with the SU-76I, and besides, there were no problems with their supply of spare parts. During the serial production of the SU-76I, 201 SPGs were produced at Plant No. 37 (including 20 "commander's" SPGs).
The units equipped with SU-76I received their baptism of fire at the Kursk Bulge. It is known that by the beginning of July 1943, the 13th Army of the Central Front had 16 SU-76s on a captured chassis, and eight such vehicles were lost during defensive battles (three were burned out). The Voronezh Front also had a certain number of SU-76Is, but the front report at the beginning of the battles gave only the total number of all self-propelled guns with a 76-mm cannon (33 pieces).
It is also known that during the offensive on Oryol, the Central Front was reinforced by two self-propelled artillery regiments, one of which also had vehicles on a captured chassis (16 SU-76I and one PzKpfw III tank).
It is reliably known that the 1902th SAP, consisting of 15 SU-76Is, arrived in the 5th Guards Army on August 2, 1943. Until August 14, the regiment was not entered into battle, but was engaged in the repair of the ACS and was waiting for replenishment by vehicles (initially the number of vehicles in the SAP was 10% of the regular strength). At the same time, five SU-122s were received to complete the regiment. From 14 to 31 August, the regiment took part in five battles (on average, 2-3 more battles than any other regiment in the army). During this period, self-propelled guns destroyed two tanks, nine guns, 12 machine guns and up to 250 soldiers and officers. According to the report of the regiment commander on September 1, “all vehicles have been damaged in previous battles. Individual vehicles were rebuilt several times, the entire materiel of the SU-76 (based on the T-3) was worn out and in poor condition.
The regiment was constantly understaffed, the training of personnel was satisfactory."
In September 1943, the regiment took part in 14 battles, in which from two to seven self-propelled guns were simultaneously introduced. Self-propelled gun fire provided substantial assistance to the infantry in repelling enemy attacks.
The most productive battles took place during September 20-23, 1943 in pursuit of a retreating enemy, when a group of six SU-76I destroyed three enemy tanks.
Usually, during attacks or pursuit of the enemy, the self-propelled guns followed directly after the tanks, and in the report of the SAP commander it was noted that if "tanks and self-propelled guns were used more massively, the losses of the regiment would be significantly reduced."
The regiment participated in combat operations until the end of November. On November 25, 1943, the 1902nd Kremenchug self-propelled artillery regiment, which lost all its vehicles, departed to be reorganized with domestic materiel.
In addition to 1902, self-propelled guns SU-76I were equipped with the 1901 and 1903 regiments, which were also used in August-September during the Belgorod-Kharkov operation.
In addition, during the Battle of Kursk, some regiments had captured self-propelled guns. For example, in the 1938 SAP of the 7th Guards Army, as of August 10, 1943, there were two SU-122, two SU-76 and two SU-75 (StuG III).
Self-propelled guns loved the SU-76I because, with a closed fighting compartment, it was not as cramped as the SU-85, or captured StuG 40. Often they had to perform typical "tank" tasks - supporting and escorting infantry, fighting enemy firing points … And only the presence of one hatch (and in 1943 there were almost no German chassis with side "hatches" left) made it difficult to evacuate the SU-76I in the event of a fire.
There is curious evidence of the SU-76I in the reconnaissance documents of the German units. So, on October 25, 1943, the headquarters of the 1st Tank Army of the Wehrmacht sent a report to the Foreign Armies - Vostok Directorate of the Abwehr army intelligence service as follows: “In the 177th tank regiment of the 64th mechanized brigade (it was part of the 7 First Mechanized Corps of the Red Army. - Author's note) there are four companies of 11 tanks each. These tanks are designated Sturmgeschuts 76mm. They are made on the chassis of the German Panzer III tank with a Maybach engine. The new wheelhouse has armor thickness in the frontal part of 3-4 cm, on the sides - 1-1.5 cm. The wheelhouse is open from above. The gun has a horizontal aiming angle of 15 degrees in each direction and a vertical aiming angle - plus or minus 7 degrees."
It is not entirely clear what this is about - after all, the self-propelled guns could not be part of the tank regiment of the mechanized brigade of the Red Army, and even in such a number - 44 vehicles. Most likely, we are talking about a self-propelled artillery regiment attached to the mechanized brigade (in this case, the number of self-propelled guns is doubled). An interesting fact is that the SU-76I (and the document is about them) has no roof. Apparently, they were dismantled to improve the actions of the crews.
In August 1943, an attempt was made in the design bureau of A. Kashtanov to strengthen the armament of the SU-76I. On September 14, the chief engineer of plant No. 37 received a letter from the head of the technical department of NKTP Frezerov with the following content: maybe due to the lack of a sufficient number of D-5 guns and the unclearness of the issue with the further delivery of T-3 tanks.
I consider it expedient to temporarily stop this development, keeping the developed material for possible use in the future. On this project, the development of domestic self-propelled guns on trophy chassis ended.
At the beginning of 1944, the chief of GABTU Fedorenko issued an order to transfer all SU-76I units from combat units to training units and to replace them with SU-76M units.
In training units, these combat vehicles met until the end of 1945, after which they were handed over for scrap. In Kubinka, the existing SU-76I prototype existed for quite a long time and was decommissioned in 1968.
The only sample of the SU-76I has survived to this day. For almost 30 years it lay at the bottom of the Sluch River, then it was raised and erected as a monument in the city of Sarny, Rivne region in Ukraine, where it is still located.
SU-76I on a pedestal in the city of Sarny in Ukraine
