Categories
WW2 Soviet Prototypes

GAZ-68 / KSP-76

Soviet Union (1943-1944)
Experimental wheeled infantry support gun (1 built)

The SU-76 remains, to this day, one of the most well-known Soviet self-propelled guns of the Second World War. Yet, at the start of its production, it was plagued by unreliability and mechanical issues caused by its drivetrain. Thus, production was halted at only 560 units in order to remedy these problems. Solutions came with the SU-76M in 1943, but in between this period, another vehicle was designed, not to replace the SU-76, but rather supplement it. This was the GAZ-68 (also later referred to as KSP-76). Meant as a desperate and ultimately unsuccessful attempt to bolster tactical mobility, it was meant to provide close support artillery for rifle and cavalry units through direct fire. The GAZ-68 was based on a truck chassis, and the main gun would still be the famous ZiS-3 field gun.

SU-76M in what seems like Berlin, 1945. The SU-76M was an attempt to fix some problems with the SU-76. The GAZ-68 was a different vehicle in its role but would have functioned alongside the SU-76s.
Source: Pinterest

Why?

Throughout the early stages of the Second World War, the Soviet military found itself in a dire need of a fast vehicle, with good firepower, able to take on German Panzers but also other targets. Mainly, it would assist the infantry units in dealing with armored and unarmored targets, but also have the capability of responding quickly, moving and penetrating deep into enemy lines, accompanied by infantry attacks. Until 1943 and ‘44, the RKKA had no designated infantry support vehicle, relying entirely on towed artillery. Using a wheeled chassis as a basis, would allow much greater on-road speed, while also, theoretically, keeping production and maintenance costs down. On paper, a vehicle like the GAZ-68 was just what the Red Army needed, but in reality, it was the complete opposite, a consequence of the Soviet war and industrial struggle. Contrary to popular conceptions, this vehicle was not meant for artillery units for indirect fire or ‘shoot and scoot’ purposes, rather just an infantry support gun.

Front of the GAZ-68 as it is preserved at Kubinka, Moscow.
Source: A. Tarasov’s personal collection

Development

Shortly after the battle of Kursk (July – August 1943), where the use of mobile defenses and counter-attacks (plus numerical superiority) proved key for the Soviet victory, the mobility of artillery and self-propelled guns proved crucial. Thus, the Gorky Automobile Plant (Gorkovsky Avtomobilny Zavod, GAZ) started the development of a wheeled infantry support gun with the approval of the head of GAZ, V.A. Grachev, who was head designer of the project, while N. Astrov was head of the project. Already in August of 1943, the design office and plant management approved the idea. Grachev, a lesser-known name within western literature, was the chief designer at GAZ between 1941 and 1944 when he created many vehicles, most notably the GAZ-64 and BA-64. Post-war, he continued his career at ZiL, where he created, among others, the famous ZiL-157 and BTR-152.

The first ideas involved mounting a ZiS-3 gun on a 1½ tonne truck chassis, with only minor modifications. Clearly, the main goal here was to get a mobile vehicle for as little money as humanly possible.

Drawings for the installation of a ZiS-3 76 mm gun on a truck chassis, which has been stripped down to the bare minimum, missing even an enclosed driving cabin. For obvious reasons, the combat value of such a creation would be extremely limited.
Source: Солянкин А.Г., Павлов М.В., Павлов И.В., Желтов И.Т. Отечественные бронированные машины. XX век. Том 2. 1941-1945

The idea of a wheeled infantry support gun interested the Soviet military, leading to a go-ahead to the project from the People’s Commissariat (Ministry) of Medium Machine Building and the Main Armored Directorate of the Red Army (GABTU). Previously, all self-propelled artillery projects were under the command of GAU (Main Artillery Directorate), until all the SPGs were re-subordinated to GABTU as Stalin personally was outraged that the GAU adopted SU-12 (SU-76) in an unsatisfactory condition. Thus, the Directorate of the Self-Propelled Artillery of the GABTU was established on the 21st of May 1943.

Work started in October of 1943 under the name ‘Izdelie 68-SU’, but this was changed to GAZ-68. By December, a wooden mockup was already completed and documentation on the vehicle from GAZ was sent to the GABTU in mid-December. The GABTU approved the project for further development. On the 7th of February, 1944, the GABTU gave a green light for the production of a prototype. It was around this time that the name ‘KSP-76’ appeared, most likely a product from GABTU to remove the GAZ factory name. It stands for Wheeled Self-Propelled Gun with a 76 mm gun (‘Kolyosnaya Samokhodnaya Pushka’, KSP).

An experimental model of the wheeled self-propelled gun KPS-76.
Curiously that the name in the document is КПС-76 (KPS-76), not KSP-76.
Source: TsAMO

Following the approval for a prototype, the design bureau quickly sent the plans and documents to the workshops, which meant that, by April, the armored hull was completed. This was designed by Y. N. Sorochkin and A. N. Kirilov and was to protect from small arms fire and splinters. To keep weight down, the top was left open. On the 4th of May, the prototype was already completed.

An important part of this quick development and production process was the use of an already tried and tested chassis (not that this meant much for the Soviets, as there were plenty of prototypes in all fields made pre-war, but in this case, it did help boost development). The GAZ-68 was based on the GAZ-63 truck, however, it needs to be pointed out that the production of the GAZ-63 began only in 1948. Rather, the GAZ-68 was based on the experimental GAZ-63 developed in 1939. Essentially this was an all-wheel-drive GAZ-51, which itself was made to replace the aging GAZ-MM. Ironically, a GAZ-MM superstructure was used for the prototype. A Dodge D5 Diesel engine was used, outputting 76 horsepower, coupled to a 4-speed transmission. These trucks were tested at Kubinka in 1940, with good results. Mass production was to begin in 1942, but the start of the Great Patriotic War (as WW2 is called in Russia) meant that all projects were canceled.

The GAZ-63 model 1939. Not to be confused with the GAZ-63 model 1948.
Source: Rus-texnika.ru

Grachev, very sensibly so, claimed that using this already finished and tested chassis would greatly increase the development speed and trials. The advantages of a wheeled vehicle over a tracked one are also clear, with cheaper maintenance and higher speeds on roads. The designers wanted to use as many readily available components as possible for reliability and production purposes. This idea was, however, the one that led to the GAZ-68’s demise.

Design

The GAZ-68 was surely an unorthodox vehicle, especially by Soviet standards. However, at its core, it was essentially a SU-76 on wheels, albeit 69 cm narrower, 65 cm lower, and 135 cm longer.

The superstructure was thinly armored, made from a simple box, and no roof. The gun was mounted slightly behind the front wheel axle. The driver was located to the right of the gun, and with the gunner to the left. Ammunition was stowed to the sides of the casemate and behind. Thanks to the long wheelbase, the vehicle was very low to the ground, ideal for ambushes and camouflage, but also offered good stability. The engine was located at the back, over the rear axles. The design was rudimentary and simple, allowing for a very cheap vehicle to manufacture if the situation of Soviet truck plants was not as disastrous as it was. The top could be covered with a tarpaulin to protect from precipitation and wind. Two large fenders would protect the front wheels. As a result of the lack of resources, automotive plants were forced to take shortcuts during production, such as fitting just a single headlamp. On the GAZ-68 it was placed on the left side fender, to not further impair the view of the driver. Coupled with the low-mounted gun, these give the GAZ-68 its iconic look.

The very low profile of the GAZ-68/KSP-76 can be seen here. It was only 155 cm tall, 54 cm shorter than the SU-76. This would have made it a smaller target, crucial for a vehicle with such little armor.
Source: Maximonline.ru

Crew

The vehicle had a crew of only 3, a gunner (who also served as a commander and radio operator), a driver, and a loader. The gunner was responsible for aiming and firing the main gun. He had two vision slits through which he could see, plus the scope of the ZiS-3 gun, extending above the frontal shield. If in doubt, he could just stick his head up to get a clear 360° view using a pair of binoculars. The gunner also had a panoramic sight at his disposal.

Overloading the gunner/commander with so many tasks is unusual for the Soviets, especially in a late 1943 design and it is noteworthy that there was also enough space in the vehicle to put a fourth crew member, although test reports claim other crew positions were cramped. It is also worth mentioning that the Soviets had already suffered catastrophic losses, especially in specialized troops, such as tankmen. This might have been a deciding factor.

Commander/Gunner’s location. Radio and equipment have been removed, but the sight is still there.
Source: svsm.org

As mentioned previously, the driver sat on the right. He had a slightly larger viewport to view out of compared to that of the commander. Oddly, the large steering wheel went above the viewport, which could have been inconvenient for taller drivers.

Driver’s position. Most of the electronics and dials have been removed, but there probably were not many to begin with. Note the large viewport.
Source: svsm.org

The loader was seated behind the gunner, on a foldable seat. He had a ready rack behind him, incorporated into the engine compartment and in front of the fuel tank, which was not very safe, but considering the overall protection, or lack thereof, it did not matter. Forty-one rounds were stored here, in a horizontal position. 13 more rounds were stored on the other side, vertically, behind the driver. The crew also had 2 PPSh submachine guns for self-defense, with 12 magazines (852 rounds).

View from the front of the rear of the fighting compartment. Note the foldable loader’s chair on the right. The rack is right behind him, but is, in this picture, almost obscured by the cover. On the left, the other rack can be seen, and other storage spots.
Source: svsm.org

Armament

The armament of the GAZ-68 was the trusty 76 mm M1942 ZiS-3 divisional gun, one of the most common guns within the Red Army at the time, and also the main weapon of the SU-76. The field gun was capable of both direct and indirect fire (once mounted on the GAZ-68 it was not). Over 100,000 units were produced by the end of the war and saw service post-war with many nations. It had a range of above 10 km and could use a variety of shells.

The KSP-76 would have most likely used AP and HE shells, but there were AP, APHE, HE, HEAT, Fragmentation, and other shells available. Most shells weighed around 6 kg and had a muzzle velocity between 680 and 700 m/s. On the KSP-76, 54 rounds were stored in total. The position of the gun in such a low profile vehicle affected its ergonomics compared to a regular field gun mount. The gun could only be elevated to +15° and depressed to -3° and had a horizontal traverse of 37°, 18.5° to both left and right sides of the gun.

The gun was supported by a travel lock mounted on the edge of the frontal slope. Despite the rather large compartment, the estimated rate of fire was 8 rounds per minute (one round in 7.5 seconds). The ergonomically well-placed ammo rack could have allowed an experienced loader to shorten the reload time even more.

The vehicle lacked any secondary armament, which was a common defect in Soviet SPGs, making them extremely vulnerable in close range combat with infantry, exactly the type of engagements the KSP-76 was meant to tackle.

View of the vertical breech and aiming system to the left.
Source: svsm.org
The iconic recoil system of the ZiS-3 mounted on the KSP-76.
Source: svsm.org

Armor

The armor of the vehicle was thin, only being able to withstand rifle fire and shrapnel. The GAZ-68 was never meant to be well armored in order to keep costs and weight down, plus its low silhouette would have played a big role in improving its survivability. The frontal plate was initially 10 mm thick, later increased to 16 mm. The top of the sides was 7 mm and the inwards angled bottom side plates 4 mm. This was not even bulletproof but would provide some protection against shell splinters and ricochets. The roof of the engine compartment was 5 mm thick but there was no protection over the heads of the crew apart from their own helmets leaving them, and some of the ammunition dangerously exposed. The cutting of corners and economy made in this aspect of the vehicle made it have a low unit production cost but would have clearly made it vulnerable to even rifle rounds from the side. The tires were bulletproof, filled with an elastic substance.

External view of the front corner, driver’s side. Note the thinness of the welded front and side plates. There were small covers for the viewports, but these seem to have vanished.
Source: svsm.org

Engine and Chassis

The chassis was, as previously stated, that of the GAZ-63 model 1939 truck. The engine and transmission were changed from the truck to a single GAZ-202 (some sources state that the engine was a GAZ-202, but the TsAMO document states that it was a GAZ-203), engine outputting 85 hp, mounted in the rear compartment, offset by 276 mm to the right. To the left of the gun, a 140 liter insulated fuel tank was placed. In front of this, the 41 round ammo rack was placed. A very scary thought, considering the armor was only a few millimeters thick! An upwards-facing cooling grille was placed in the back. The transmission was a 5-speed manual (4 forwards, 1 reverse) coupled to both axles. However, the rear axles could be disconnected from the drive when not needed such as on a long road march. The suspension was standard and common to the truck consisted of simple leaf springs and shock absorbers.

Rear top view of the prototype. The rear compartment housed the engine, transmission, fuel tank, and ammunition, with only 4-7 millimeters of protection.
Source: Topwar.ru

Trials and Fate

As soon as the prototype was finished, it began factory testing around May 1944 and had finished tests by autumn of the same year. From the Gorky factory, the GAZ-68 went to the Kubinka test range. Allegedly, it traveled under its own power and with an impressive speed of 60 km/h. Again, this information has to be taken with a grain of salt.

In September-December 1944 the experimental SPG was tested at Kubinka proving grounds and Gorokhovetskii artillery range. During a 2,528 km test drive, it is claimed to have reached a top speed of 77 km/h on-road, but this seems hardly possible in regular conditions. Even if it was true, the limited view of the driver would make such a speed hazardous, to say the least. The vehicle only had an 85 horsepower engine and weighed 5,430 kg battle-ready. During firing trials, 409 shots were fired of unspecified type at the Gorokhovetskii artillery range.

However, testing was not all going to plan for the Soviets. The original chassis took a hard beating and broke down frequently, putting into question the validity of the tests made at Kubinka of the GAZ-63. The driveshafts, gearbox, leaf springs, and frontal axle suffered some form of damage. To be fair, the GAZ-68 did weigh over 2 tonnes more, with different weight distribution. It was also noted that the crew compartment was too small and uncomfortable for some of the crew, especially the driver, who was cramped up by the gun and steering wheel.

The small silhouette and profile of the vehicle were deemed as a plus. However, there were significant issues with accuracy, thanks to the chassis and the suspension, which made the ride very bouncy. This also caused the sight and barrel to become misaligned after driving. Off-road tests were a mixed bag. On one hand, the GAZ-68 proved satisfactory, on the other, it was far inferior to what a tracked vehicle was capable of. Testing was finished by the 24th of December. The Military Council of the Armored and Mechanized forces of the Red Army (Военный Совет БТ и МВ КА, Voennii Sovet Bronetankovyh i Mekhanizirovannyh Voisk Krasnoi Armii), proposed to GOKO (State Committee on Defence) to produce the initial test batch of 10 units at the GAZ factory and undergo army tests. However, this was not achieved and, instead, the project was terminated altogether.

The situation of the war in mid-1944 was very different than that of a year earlier. The Red Army had been on the offensive for almost a year, pushing the Axis almost back to the pre-war borders, and the Allies had just landed in Normandy, sealing the fate of the war. The implementation of the GAZ-68 made even less sense now than it did before, and the questionable combat value it would have brought would far outweigh the industrial strain, despite the seemingly cheap production price.

Doomed from the start

Even before starting prototype production, the fate of the GAZ-68 was predetermined. The straightforward fact that it was based on a truck chassis, which for the designers certainly seemed like an advantage, but the industrial capabilities and resources of the USSR could not deliver. The Soviet industry could not keep up production of ZiS-5 and GAZ-AA simple flatbed trucks, even with help through the Lend-Lease program, let alone the mass-production of an even more complicated truck designed in 1939 and canceled because of the German invasion.

Automotive factories could not start assembly of a new, complex, and relatively new design, in the conditions that they could not even keep up with simple production models. It is important to note, both of these truck models were standard commercial trucks, with little to no improvements for off-roading or any sort of military specialization. Before the war, the Red Army only had the GAZ-M1 and no off-road trucks.

Side view of the prototype showing off the impressively low profile to a good extent. Note the tarpaulin and muzzle cleaning rod.
Source: Topwar.ru

The GAZ-68/KSP-76 was also doomed through its design. The use of wheels would have given it faster speeds on good terrain, but most of the western Russian terrain was flat plains and forest, with poor road connections. This is not to take into account the harsh conditions of thick winter snow or deep muds, where even tracked vehicles could struggle. The supply of tires before and during the war was also a big issue for the Red Army. While the situation to some extent improved during the war, they still relied on imported tires for around 33% of their needs.

In modern eyes, a wheeled vehicle might seem superior, as we now have many roads and good infrastructure, plus more advanced technologies, but this was Russia in 1943. The GAZ-68 was simply not compatible with Soviet military doctrine, industrial capabilities, and the terrain of Eastern Europe.

Compared to the SU-76, the GAZ-68 was far cheaper to build and maintain, was 54 cm lower, but with similar protection levels and firepower, in addition to the pros and cons of a wheeled chassis. Whether the KSP-76 was an improvement over the SU-76 is up to debate, but it clearly was not enough to justify the changing of truck production lines to a new vehicle this late into the war.

GAZ-68/KSP-76 illustrated by Pavel Alexe, funded through our Patreon Campaign

GAZ-68 / KSP-76 specifications (Source: TsAMO)

Dimensions (L-W-H) mm 6,350 / 2,050 / 1,550
Total Weight, Battle Ready 5.39 tonnes
Crew 3 (Commander, Driver and loader)
Propulsion X
Speed X km/h
Range X km
Armament 76 mm gun ZiS-3 M1942 Regimental gun (662 m/s muzzle velocity)
Ammunition count 54
Maximum speed, km/h 62.5
Average speed on a paved road, km/h 49.3
Average speed on an unpaved road, km/h 21.2
Engine GAZ-203 (with an aluminum head) outputting 85 hp
Fuel type and range KB-70 or B-70 fuel,
140 liters for 430 km range
Armor (frontal hull, fighting compartment), 7-16 mm
(Sides, rear hull and fighting compartment), 4-7 mm
Total Production 1 prototype

Sources:

https://topwar.ru/51030-kolesnaya-sau-gaz-68-ksp-76.html
S. Lopovok, Inventor and Rationalizer, No 12,
Zaloga, Steven J., James Grandsen Soviet Tanks and Combat Vehicles of World War Two
https://rus-texnika.ru/gaz-62-obrazca-1939-goda.html
A.V. Karpenko. Part 1. Light self-propelled artillery installations  Domestic self-propelled artillery and anti-aircraft installations
https://rus-texnika.ru/gaz-63-obrazca-1939-goda.html
https://tech.wikireading.ru/9308
Солянкин А.Г., Павлов М.В., Павлов И.В., Желтов И.Т. Отечественные бронированные машины. XX век. Том 2. 1941-1945
TsAMO & GABTU archives (from A. Tarasov)

Red Army Auxiliary Armoured Vehicles, 1930–1945 (Images of War)

Red Army Auxiliary Armoured Vehicles, 1930–1945 (Images of War), by Alex Tarasov

If you ever wanted to learn about probably the most obscure parts of the Soviet tank forces during the Interwar and WW2 – this book is for you.

The book tells the story of the Soviet auxiliary armor, from the conceptual and doctrinal developments of the 1930s to the fierce battles of the Great Patriotic War.

The author not only pays attention to the technical side, but also examines organizational and doctrinal questions, as well as the role and place of the auxiliary armor, as it was seen by the Soviet pioneers of armored warfare Mikhail Tukhachevsky, Vladimir Triandafillov and Konstantin Kalinovsky.

A significant part of the book is dedicated to real battlefield experiences taken from Soviet combat reports. The author analyses the question of how the lack of auxiliary armor affected the combat efficacy of the Soviet tank troops during the most significant operations of the Great Patriotic War, including:

– the South-Western Front, January 1942
– the 3rd Guards Tank Army in the battles for Kharkov in December 1942–March 1943
– the 2nd Tank Army in January–February 1944, during the battles of the Zhitomir–Berdichev offensive
– the 6th Guards Tank Army in the Manchurian operation in August–September 1945

The book also explores the question of engineering support from 1930 to the Battle of Berlin. The research is based mainly on archival documents never published before and it will be very useful for scholars and researchers.
Buy this book on Amazon!


One reply on “GAZ-68 / KSP-76”

Top speed of a vehicle is not defined by its engine power or its power to weight ratio. It is rather defined by its friction with a ground and internal elements. Thus, what limits top speed is largely vehicle’s suspension and soil characteristics. If forces urging vehicle to move forward are stronger than forces holding it back, vehicle will keep increasing it speed no matter how underpowered it is. Vehicle’s engine comes into play only when trying to have more power to overcome those forces. However, even modern vehicles are not much better in this regard due to the fact that various friction tend to increase exponentially with speed.

Due to this, I find it quite believable that this vehicle could drive at 77 km/h at right conditions.

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