Categories
WWII Soviet SPGs

SU-26

USSR Soviet Union (1941-1944)
Assault Gun – 14 built

Mobile Fire Support

World War I led to the creation of a myriad of new weapon platforms, which include the Self Propelled Gun (SPG) and Assault Gun types. These vehicles had to provide direct or indirect fire support, while also having decent mobility and light armor protection. An Assault guns job was generally as a direct fire support weapon which means that a heavy gun was used to directly fire in line of sight at a target. A Self Propelled Gun was used for indirect fire support, this is where direct line of sight is not the means of aiming the weapon, and is generally a mobile artillery piece. World War II saw the implementation of the widest array of such vehicles, including the StuG III (Assault Gun), M7 Priest (SPG) and SU-76 (Both an SPG and Assault Gun).

Early T-26 Gun Platforms

The T-26 tank was, at its core, a Soviet manufactured copy of the Vickers 6 Ton tank. As soon as it was introduced into Red Army service in 1931, methods of converting the tank into an assault gun or SPG began to be explored.

SU-1

The first attempt at such a vehicle on the T-26 chassis was the SU-1. SU comes from Самоходная установка, Samokhodnaya Ustanovka, which means self-propelled gun in Russian. This was a very early attempt at an assault gun, being manufactured in 1931. It had a simple superstructure that held a KT-28 gun. The superstructure was similar to that of the production T-26, but it was taller and had a commander’s cupola. However, it did not enter production as it was deemed that the T-26-4 prototype would render the SU-1 redundant. In addition, shortly before cancellation, the interior was deemed inadequate for the crew to operate effectively, this was due to the interior being too small to effectively operate the gun and stow ammunition. The basic layout of this machine was used for the AT-1 prototype.
The SU-1 prototype, Notice the 76.2 mm (3 in) KT-28 gun in the hull, with the gun recuperator system exposed.
The SU-1 prototype, Notice the 76.2 mm (3 in) KT-28 gun in the hull, with the gun recuperator system exposed.

AT-1

The AT-1 is perhaps the best known Assault Gun of the pre-war Red Army. This was a modified SU-1, with the KT-28 gun replaced by a PS-3 76.2 mm (3 in) gun. The vehicle was tested and it was found that the interior of the tank was insufficiently large. However, before the problems could be ironed out, the designer, P.N.Syachintova, was arrested and the project subsequently shelved.
The AT-1 prototype. Notice the similarities to the SU-1, with the exceptions of the gun and subtle superstructure changes.
The AT-1 prototype. Notice the similarities to the SU-1, with the exceptions of the gun and subtle superstructure changes.

SU-5

Later, in 1933, a new self-propelled gun was developed on the aforementioned T-26 chassis. This time, two guns were trialed: a 122 mm (4.8 in) howitzer and a 76.2 mm (3 in) Model 1902/1930 gun. The upper hull of the regular T-26 was relatively unchanged. However, instead of the turret ring, a hatch that allowed access to the internal ammunition stowage was installed. At the rear of the tank, over the engine compartment, were placed the gun mount, the crew positions, a small gun shield and two deployable legs for firing the gun. This self-propelled gun was known as the SU-5. This weapon platform would be an SPG rather than an Assault Gun due to the nature of the 122mm Howitzer and the maximum angle of the main armaments.
The SU-5-1 equipped with a Model 1902/1930 76.2 mm (3 in) gun.
The SU-5-1 equipped with a Model 1902/1930 76.2 mm (3 in) gun.
The SU-5-1 was equipped with the 76 mm (3 in) gun or the 122 mm (4.8 in) gun, whereas  the SU-5-2 was only equipped with the 122 mm (4.8 in) howitzer. The SU-5-2 differed slightly, with a strengthened hull and suspension. SU-5-1s were manufactured in 1936 in a small batch of 23 machines. Shortly thereafter, the Su-5-2 was accepted for production. However, only 20 production vehicles were manufactured. Of these machines, only 18 were still in service in June 1941.
The only surviving report of the SU-5-2 is from the 67th Tank Regiment, where they were used alongside T-35 heavy tanks. These machines were lost during the opening days of the war, with one of the production tanks being reported to have been lost in the village of Gorodok (modern day Horodok) in the Lviv Oblast, where the repair center for the 67th Tank Regiment was based. A second machine was sent to Lviv for repair, however its fate is unknown. Other Su-5s were mostly deployed in the Far East and therefore survived the war to be scrapped.
The SU-5-2  equipped with the 122 mm (4.8 in) howitzer. Notice that the exhaust has been moved to the left side of the vehicle, and two legs have been added.
The SU-5-2 equipped with the 122 mm (4.8 in) howitzer. Notice that the exhaust has been moved to the left side of the vehicle, and two legs have been added.

SU-6

From 1928 to 1941, the Soviet Union also looked into self-propelled heavy Anti Aircraft (AA) guns. One such prototype was the SU-6. This was a heavily redesigned T-26 hull, with a collapsible superstructure and a 3K 76.2 mm (3 in) AA gun. The collapsible superstructure allowed for maximum space for the crew while operating the gun, however allowed the tank to stay the same dimensions as a regular T-26 when in travel mode. This tank was trialed in 1936, but the project was dropped. 7 hulls had been manufactured, and mass production was about to begin. However, all of the hulls were seized due to the designer’s, P.N.Syachintova’s, arrest and subsequent execution on Stalin’s orders.
The SU-6 prototype. Notice the collapsible sides with supporting and levering arms under the sides. This machine could have been a potent weapon.
The SU-6 prototype. Notice the collapsible sides with supporting and levering arms under the sides. This machine could have been a potent weapon.

The Disaster Of Barbarossa

None of the mentioned self propelled guns were successful or produced in high numbers. Therefore, there were few direct or indirect fire support vehicles ready for front line service in June 1941. Several tank variants could provide this assistance, but their numbers were low, they were required to do other jobs such as be a main battle tank, or they were entirely obsolete. Such examples include the KV-2 with a 152 mm (6 in) howitzer, the T-28, T-35 and the BT-7 Artillery version, all having the KT-28 gun. While these tanks were not inadequate, many designs dated back to the early 1930s, or were mechanically unreliable.
While not a must-have weapon, self-propelled guns could have provided a mobile mean of light direct or indirect fire to harass approaching enemy units, to set up mobile defensive points, or simply for mobile anti-tank duties. There are obvious advantages over a typical Field Gun, as the resources needed for towing and deploying it vastly outnumber the resources needed for a typical Assault Gun. The majority of Field Guns of 1941 were horse drawn, with crews numbering upwards of 8 or 9 men. In addition the ammunition for such guns had to be transported separately, these issued are solved in an Assault Gun.
In the subsequent months after Operation Barbarossa, The German invasion of the Soviet Union, scores of T-26 tanks were lost either due to combat, breakdown, or lack of fuel or ammunition. Between June and October 1941, 10,000 Soviet tanks were lost. The obsolescence of the T-26 Model 1931 and 1932 in particular were clear to the red army in 1941. There was still 450 such machines in the Red Army in June 1941, 87 of which were in the Leningrad Military District. Even before the war, it was discussed what should be done with the machine?  The Subsequent invasion of the Soviet Union, and impending arrival of German troops at Leningrad gave the Soviet engineers at Factory 174 within Leningrad a myriad of vehicles on which to experiment. One such experiment was a small, mobile self-propelled gun meant to assist the defenders.
A propaganda photograph of Plant 174 with SU-26s being manufactured. Notice that the axis point for the gun shield is being lifted onto the hull of the foremost vehicle.
A propaganda photograph of Plant 174 with SU-26s being manufactured. Notice that the axis point for the gun shield is being lifted onto the hull of the foremost vehicle.

A SU-26 in winter camouflage.
A SU-26 in winter camouflage. 
A SU-26 in the olive 4BO green that they would have been given as a base camouflage. It is known that some tanks were painted three tone, and others were given divisional numbers on the gun shield.
A SU-26 in the olive 4BO green that they would have been given as a base camouflage. It is known that some tanks were painted three tone, and others were given divisional numbers on the gun shield.
Once German troops approached Leningrad in Late September 1941, the question of obsolete tanks in operation was discussed once again, therefore on August the 5th 1941, Plant 174 presented a new Assault Gun to The Military Council Of The Leningrad Military District. This machine was called the T-26-6. This was done because the need for a direct fire support weapon was high, as troops needed more direct medium or heavy fire support weapons, and it was a useful way of utilizing obsolete types of T-26 tanks.On August 11th, the project was given the green light by the Leningrad Military Council, however two of the 24 hulls earmarked for converting had already been worked on. This new Assault Gun was armed with a 76.2 mm (3 in) KT-28 gun, However two 37 mm (1.46 in) guns were also mounted according to the documentation. The hull and engine deck were redesigned to create a flat platform. A traversable mount was added onto the tank, with a large gun shield, large enough to protect the crew crouching. The gun was mounted in the center of the shield. The original driver’s compartment was kept, but the rest of the superstructure was eliminated to make way for the gun and its mounting.
Another view inside the plant, this time from the opposite end of the floor. Notice that the KT-28 gun is missing the recuperator system armor.
Another view inside the plant, this time from the opposite end of the floor. Notice that the KT-28 gun is missing the recuperator system armor.
The gun shield had a hole for the KT-28 gun in the center, with two small ports on either side of it, in which two DT-29 machine guns could be mounted. Normal operation of the mount was with the gun facing to the rear of the machine to allow for greater crew mobility. However, the vehicle could also operate with the gun firing forwards.
Shortly after production began however, it was decided that some of the chassis would remain as T-26 tanks as stocks of the tanks began to run short. Therefore, only 14 SU-26s were manufactured, with other chassis going towards Flame Throwing Tanks (8), and the retention of 4 twin turreted T-26s. It is likely that less twin turreted tanks were manufactured, as 24 chassis divided between the numbers provided leaves -2 tanks (it is also possible that the two 37mm equipped Su-26s are actually simply T-26s Model 1932s that were retained in the paperwork).
A SU-26 in a static defense position. Notice how the crew compartment has been cut out from the original superstructure. Two DT-29s can be seen on either side of the gun
A SU-26 in a static defense position. Notice how the crew compartment has been cut out from the original superstructure. Two DT-29s can be seen on either side of the gun.
These machines were known as the SU-T-26s, T-26-SU or, more commonly, SU-26 and SU-76. SU-76 was the more common name in the records of the Red Army. However, it was changed to SU-76P (Regimental), after the introduction of the T-70 based SU-76. This was due to the KT-28 being a Regimental Gun, whereas the T-70 Su-76 was fielded with a 76.2mm Zis-3 Anti Tank Gun.
A blown up SU-26. Notice that the engine deck is still accessible
A blown up SU-26. Notice that the engine deck is still accessible.
It is known that the 124th Armored Brigade was issued the two 37 mm gunned versions, and three 76.2 mm (3 in) gunned tanks were reported as being lost in combat with that unit. Another unit that used these machines was the 220th Tank Brigade, which was issued four 76 mm gunned vehicles. In early 1942, an indipendant Anti Tank Battalion was created, namely the 122th Tank Brigade. This fielded Su-26s. Interestingly, these machines are supposed to have been operational up until 1944 in the Leningrad pocket. It is fair to suggest that these machines were true desperation weapons, with a poorly designed exposed gun platform. As only 14 were manufactured, too few Su-26s were manufactured to adequately analyze the effectiveness of the machine.
A propaganda photograph of a SU-26 on the advance.
A propaganda photograph of a SU-26 on the advance. 
The same propaganda film as above. Notice how the fenders have been lifted to allow for a flat platform for the crew.
The same propaganda film as above. Notice how the fenders have been lifted to allow for a flat platform for the crew.

A Su-26 that likely served in the 122th Tank Brigade. Notice the interesting camouflage exhibited on this machine, with a base coat of white (over olive) with further olive painted on lines over the white.

Su-26 specifications

Total weight, battle ready 12 tonnes
Crew 4 (Driver, Commander, Gunner, Loader)
Propulsion T-26 Carburetor, 4 Cylinder, 90 hp
Suspension 4x pivot bogie pairs
Armament 37 mm (1.46 in) or 76.2 mm (3 in) KT-28
2x DT-29
Armor 10-20 mm (0.39-0.79 in)
Total production 14

Sources
The SU-1 on Aviarmor
The SU-5 on Aviarmor
The SU-6 on Aviarmor
The SU-26 on Aviarmor
The SU-26 on Warspot.ru
tanks posters - Soviet Armour 1941
Soviet Tanks in June 1941 (Operation Barbarossa)

Categories
WWII Soviet SPGs

SU-76i

Soviet Union (1942-45) Self-propelled gun – 181 built

The Red Army’s Panzer III 76mm SPG

The SU-76i was built or re-built by the Soviets because, while speeding up their huge production of tanks, they still faced shortages in certain areas. Furthermore, the original SU-76 model had several flaws. They were unreliable and not a pleasure to drive, so much so the Soviet tankers named it “the Bitch”. During the fall of Stalingrad, the Soviets had captured several StuG and Panzer III tank chassis in relatively good condition. With the thought of rearming them with bigger Soviet guns, they were shipped back to factory 37 at Sverdlovsk.
SU-76i self-propelled gun was armed with a 76.2 mm (3 in) S-1 anti-tank gun
The SU-76i self-propelled gun was armed with a 76.2 mm (3 in) S-1 anti-tank gun
By early 1943, the Soviets had some 300 StuGs and Panzer IIIs and decided to mount 76.2 mm (3 in) Zis-3sh guns into their hulls. The resulting non-turreted tank destroyer was meant to fill in the gaps where SU-76s had been destroyed or sent back for repairs. The initial design was to mount the 76.2 mm on a semi traversable pedestal similar to early Italian TD’s, but this left the crew very exposed, more so than the SU-76, and would have left the tank defenceless against close artillery blasts and shrapnel. The gun was then to be mounted in a fixed casemate with limited traverse and a shorter, but more powerful 76.2 mm S1 gun was chosen.
Hinged pistol holes with an armored cover were inserted in the upper slab sided armor plate. This enabled the crew to fire their hand held weapons at enemy infantry that were getting too close. A vision slit was fitted above the pistol hole.
The hull mounted machine gun found on the Panzer III tank was removed on the SU-76i SPG. The driver sat on the left and had limited vision. He could only see directly ahead and to his left through an armored vision slit.
The prototypes were ready by March 1943 and sent for testing to the Sverdlovsk grounds. Even while the weather was extremely cold, with temperatures at -35 degrees Celsius, the new tanks destroyers, with their durable German components, passed the test. A few modifications were made, including oil heaters to stop the engine from freezing and other minor changes to batteries and sights. They were given the designation SU-76i, with the letter ‘I’ standing for ‘Inostrannaya’ or foreigner. It seems the hatred for Germans was even placed upon their equipment. The new SU-76i would have to prove itself.
This Su-76i SPG does not have the external fuel tanks fitted to on the rear of the vehicle or the armoured engine hatch covers.
This Su-76i SPG does not have the external fuel tanks fitted onto the rear of the vehicle or the armored engine hatch covers.
Some 181 of these tank destroyers and 20 command vehicles were built by November 1943. Production was stopped after that date, mainly because, by then, the original SU-76 had all of its bugs rectified and was running well. The other reason was cost; stripping down and rebuilding a knocked out or captured Panzer III was harder than building a new SU-76, which could now be easily repaired and updated.
The SU-76i self-propelled gun was in some ways better than the SU-76 standard version. It had better armor, with 35 mm (1.38 in) of frontal plate, 25 (1 in) on the sides and about 15 mm (0.59 in) on the back. The SU-76 on the other hand, had only enough armor to stop small arms fire and splinters. The second and more important thing to those that drove it was that the SU-76i was fully enclosed. This made a huge difference to morale in the biting Russian winds and harsh temperatures present during that winter, and SU-76i crews could stay snug inside the vehicle by keeping the engine ticking over.
This Su-76i SPG does not have the external fuel tanks fitted to on the rear
This Su-76i SPG did not have the external fuel tanks fitted onto the rear of the vehicle
The superstructure itself was of a welded design which, while more expensive than bolting, was necessary as the tank was not being made out of pre-fabricated parts, but was rather a chop shop job. Only the roof was bolted on, and this as a single piece to increase its strength. It was not unheard of for crew to remove this roof during the hot summer months and use the vehicle as an open topped tank.
The command tanks did not remove their roof and kept the original German commander cupola in situ. Their left ammunition bank was removed in order to fit an extra radio with improved signal capabilities in place.
Very few modifications were made or needed to the SU-76i. A reinforced shield was added over the mantle to stop stray rounds, and small changes were made to the suspension, as the Soviets had no natural replacement parts for this. The torsion suspension, on the other hand, was durable and lasted well. Despite its radical facelift and altered parts, the SU76i handled very well and was popular with its crews, despite its original heritage.
SU-76i SPGs were used on the Eastern Front during the winter of 1943-44
SU-76i SPGs were used on the Eastern Front during the winter of 1943-44

Active Service

The SU-76i self-propelled guns fought from spring 1943 until early spring 1944. They were part of the Soviet armored forces at the battle of Kursk, where they were attached to the 5th Guards, 13th Army of the Central Front. Eight were lost and three totally burnt out.
During the assault on Orel, in late July 1943, sixteen SU-76i SPGs were deployed in operations. The Voronezh front saw the same number in action. Many were destroyed in the German counter attack near Prokhorovka. They saw action in South Russia and northern Ukraine.
After 1944, unlike many captured German tanks that were scrapped immediately when they were of no further combat use, the SU-76i had earned a warm place in the hearts of a few and as such the surviving 10-15 vehicles went on to be training vehicles at tank and artillery schools.
SU-76i Command Vehicle with Panzer III cupola fitted to the roof
SU-76i Command Vehicle with Panzer III cupola fitted to the roof

The SU-76i command vehicle version

Twenty SU-76i self-propelled guns were constructed as command vehicles. They had an improved high powered radio and a Panzer III commander’s copula fixed on the roof. Less ammunition was carried to give extra room for the radio and maps.

The Gun

The 76.2 mm (3 in) S1 gun could fire high explosive HE shells, as well as armor piercing rounds. Firing as an artillery gun using HE shells, it had a maximum range of 13.29 km (8.25 miles). Its armor piercing rounds could penetrate 75 mm (2.95 in) of armor plate at a distance of 500 m and 82 mm (3.23 in) at 100 m range, when the armour was at a 90 degree angle. It could not penetrate the front armor of a Tiger tank, but could knock out a Panzer III or IV tank.
An article by Ed Francis

Specifications

Dimensions (L-W-H) 5.56 x 2.90 x 2.5 m
( 18’3″ x 9’6″ x 8’2″)
Crew 4 (driver, commander, gunner loader)
Propulsion 12-cylinder Maybach HL120 TRM, 296 bhp
Top road speed 40 km/h (25 mph)
Operational Range 165 km (103 miles)
Armament 76.2 mm (3 in) S-1 gun with 48 shells
Hull Armor Front 30 mm, sides 30 mm, rear 20 mm (1.18, 1.18, 0.8 in)
Upper Armor Front 35 mm, sides 25 mm, rear and roof 15 mm (1.38, 1 ,0.59 in)
Production Around 181 SU-76i
+20 Command Vehicles

Sources

aviarmor.net
valka.cz
Pejčoch: Obrněná Technika
The SU-76i on Tank-Hunter.com
The SU-76M on Wikipedia
Battlefield.ru
The SU-76 on WWIIVehicles.net

Battle of Kursk SU-76i attached to the 5th Guards.
Battle of Kursk SU-76i attached to the 5th Guards.
SU-76i in winter camouflage, Eastern Front, 1943.
SU-76i in winter camouflage, Eastern Front, 1943.
SU-76i command tank variant with Panzer III tank cupola fixed to the roof.
SU-76i command tank variant with Panzer III tank cupola fixed to the roof.

Gallery

Soviet SU-76i SPG, Eastern Front, Winter 1943-44
Soviet SU-76i SPG, Eastern Front, Winter 1943-44
Only the command version of the SU-76i SPG was fitted with a cupola - Eastern Front, Winter 1943-44
Only the command version of the SU-76i SPG was fitted with a cupola – Eastern Front, Winter 1943-44
Rear view of a SU-76i SPG. Notice the large crew hatch, armored engine hatch covers and external fuel containers.
Rear view of a SU-76i SPG. Notice the large crew hatch, armored engine hatch covers and external fuel containers.

Surviving SU-76i SPGs

This SU-76i Soviet SPG can be found in the Central Museum of the Great Patriotic War 1941 - 1945, Park Pobedy, Moscow Russia
This SU-76i Soviet SPG can be found in the Central Museum of the Great Patriotic War 1941 – 1945, Park Pobedy, Moscow Russia.
The SU-76i driver could only see straight ahead and to his left. Notice the vision slit above the covered pistol hole on the left side of the armored casement.
The SU-76i driver could only see straight ahead and to his left. Notice the vision slit above the covered pistol hole on the left side of the armored casement.
The SU-76i Soviet SPG was armed with a 76.2 mm (3 in) anti-tank gun. It is missing the additional gun shield and dust cover.
The SU-76i Soviet SPG was armed with a 76.2 mm (3 in) anti-tank gun. It is missing the additional gun shield and dust cover.
Surviving SU-76i self-propelled gun used as a war memorial in Sarny, Rivne Oblast, Ukraine.
Surviving SU-76i self-propelled gun used as a war memorial in Sarny, Rivne Oblast, Ukraine.
SU-76i Command Tank replica at the Museum of Military Equipment Battle Glory of the Urals, Verkhnyaya Pyshma, Sverdlovsk, Russia
SU-76i Command Tank replica at the Museum of Military Equipment Battle Glory of the Urals, Verkhnyaya Pyshma, Sverdlovsk, Russia
ww2 soviet armour
All ww2 Soviet Tanks Posters

Categories
WWII Soviet SPGs

ISU-122 & ISU-122S

Soviet Union Soviet Union (1944-1952?) Heavy self-propelled gun – Estimated 2,410 built

An under-gunned ISU-152

The ISU-122 was a heavy self propelled gun, and de facto tank destroyer. The vehicle came to be because the Soviets were able to produce ISU-152 hulls faster than they could produce their 152 mm (6 in) ML-20S armament. Not wanting to slow down heavy tank production, it was realized that there was a surplus of 122 mm (4.8 in) A-19 guns, and thus the problem was solved – the two were mated. Much like its older brother, the ISU-152, the ISU-122 saw action as a multi-role vehicle, but it was used as a tank destroyer more than the ISU-152 because its 122 mm gun was much more accurate than the 152 mm ML-20S howitzer. However, postwar, the ISU-122 was deemed unsatisfactory, and many were later refitted for other military uses, such as armored recovery vehicle. Many were disarmed, and handed over for civilian purposes, such as working on railways.

Design process

The creation of the ISU-122 was a direct result of ISU hulls having production speed stepped up, but their ML-20S armament’s production speed being kept the same. State authorities wanted to speed up tank production, and were not willing to wait for new 152 mm (6 in) guns to be produced. As a result of this lack of armament, the stock of surplus A-19 122mm guns were mounted instead, and, rather handily, the A-19 and ML-20 field guns were both mounted on the same towing carriage (the 52-L-504A), and so the gun mount in the ISU’s hull needed little redesigning to fit the new gun.
The A-19 was modified to fit tanks, and was designated A-19S, but as a result of the manual-piston breech, the rate of fire was reduced from 2.5 to a mere 1.5 rounds per minute. This was hardly an under-armament, because it excelled at providing effective direct fire at enemy heavy tanks – something that the ISU-152 was known for, but did not excel at in reality. Seeing the huge benefit over the ISU-152 for this role, the State Defense Committee accepted the Object 242 (as it was known during tests) as a new design, as opposed to a stopgap improvisation on April 12th, 1944, and the first vehicles left the ChTZ factories in the same month.

Hello dear reader! This article is in need of some care and attention and may contain errors or inaccuracies. If you spot anything out of place, please let us know!
When the ISU-122’s production ended seems to be open to debate. According to some sources, production was concluded at the end of 1945, but, according to other sources, most notably, Zaloga’s “IS-2 Heavy Tank, 1944-1973”, production resumed in 1947 until 1952, with 3130 produced, for unstated reasons. It is possible that there were large stocks of A-19 or D-25S guns that needed using up. The total number produced remains unclear, with many sources giving figures not even close to the other. The highest estimate is over 5000, and lowest at roughly 2000.
In the 1950s, many ISU-122s were converted for civilian use (such as on the railways or even reportedly in the arctic as transport vehicles). Many others were converted into ARVs, and some others into heavy rocket launching platforms.  However, the few ISU-122s that were not converted were modernized in 1958, similar to the ISU-152 modernization. However, it was not as thorough, and most only received upgraded gun sights and radio sets, with some few getting a new engine. The ISU-122 was totally withdrawn from service by 1960.

Variants

ISU-122S

Realizing that the A-19S had a slow rate of fire, the famous D-25 gun was later fitted. D-25S production was prioritized to be fitted to IS-2s, but as more became available in late 1944, they were fitted to the ISU hull. This variant passed trials in late 1944 and was referred to as the Object 249 or ISU-122-2. Rate of fire was now 2-3 shots per minute, and even 4 shots per minute with experienced loaders.
The easiest way to spot this variant is by the double baffle muzzle brake or by the ball-shaped gun mantlet. The D-25S’ muzzle brake reduced the recoil force from firing the gun and made working conditions better for the crew, as well as allowing a smaller, lighter gun mantlet being mounted, but with the same effective armor protection due to its round shape. 675 ISU tanks were fitted with the D-25 gun, but because of the huge stocks of the A-19, both the ISU-122 and ISU-122S were produced until the end of 1945.

BTT-1 and ISU-T

These were armored recovery vehicles based on the ISU-122. Because the ISU-122 was effectively redundant after WWII, they were converted for many other uses. The ISU-T was an early version that was made in the early 1950s, by simply removing the gun and placing a metal sheet over the top. However, this was little more than a cheap conversion. In 1959, the BTT-1 was designed as a more serious and better equipped vehicle.
Essentially the same as the ISU-T, they also had any combination of: a basket mounted on the rear deck, a winch, crane, a dozer blade (of various sizes) and other towing equipment. In 1960, modernization of these vehicles took place which saw another generator added to the vehicle to allow welding and field repairs of vehicles. There was also fairly little standardization of the vehicle, with some featuring local modernization with A-frame cranes.
Further details on the vehicle are scarce, but it appears that many different countries used this vehicle, such as Egypt, the USSR, Poland, and Czechoslovakia. Egypt seemed to get their BTT-1s along with a purchase of a regiment of ISU-152s in the early 1960s. At least one was captured by Israel during either the 1967 or 1973 war, and now stands at Yad La-Shiryon Museum.
A captured Egyptian BTT-1 armored recovery vehicle at Yad la-Shiryon museum, Israel
A captured Egyptian BTT-1 armored recovery vehicle at Yad la-Shiryon museum, Israel.
An ISU-T armored recovery vehicle preserved in Poland
An ISU-T armored recovery vehicle preserved in Poland.

ISU-122E

According to Zaloga, this was a very short-lived project designed with wider tracks and heavier armor. It was designed to be protected against German 88 mm (3.46 in) guns, but it was not accepted into service due to its significantly reduced mobility.

“ISU-122BM” projects

These “BM” or “High Powered” projects were attempts in mid-1944 at Zavod Nr. 100 at making the ISU chassis into a dedicated heavy tank hunter capable of destroying the King Tiger and Jagdtiger. Many designs were made from June 1944 right up to the end of 1945, using various calibers such as 122 mm, 130 mm, and 152 mm. For the 152 mm projects, see the ISU-152 article. None of the “BM” designs were accepted for a variety of reasons, such as poor gun handling, excessively long barrel length (thus making maneuvers in urban areas difficult), the lack of King Tigers (and similarly armored vehicles) expected to be encountered, and the relative sufficiency of ISU-122S and IS-2 tanks at dealing with these heavily armored rarities.

ISU-130

The ISU-130 was built in autumn, 1944 and featured a 130 mm (5.12 in) S-26 gun. This gun is sometimes referred to as a naval gun, but this is not entirely accurate – the S-26 derived from a naval gun, and featured a muzzle brake and horizontal wedges. In October, 1944, the ISU-130 underwent factory trials, and the following month, trials were held at the Polygon. Testing ended in 1945, and the gun was sent to the TaSKB for completion, but the war was over, and the project was disbanded. Its main advantage was that, whilst it provided similar ballistic results to the high powered 152 mm projects, it had smaller shells, which meant the vehicle could carry 25 shells, as opposed to 21. It had a muzzle velocity of 900 m/s, and a range of 500 m, placing it in roughly the middle of all “BM” project guns. It is currently preserved at Kubinka Tank Museum.
The ISU-130 on display at Kubinka
The ISU-130 on display at Kubinka.

Object 243

The Object 243, or ISU-122-1, featured a 122 mm BL-9 gun – one of the infamous BL guns made at OKB-172. It essentially looked like a longer version of the A-19S, although the gun mantlet had some tweaking to fit the longer and heavier gun. It could carry 21 AP rounds. Its muzzle velocity was 1007 m/s, which was the highest of all “BM” guns.

Object 251

The ISU-122-3 (-2 was the ISU-122S with the D-25S) was derived from the ISU-130. It featured essentially a 122 mm version of the 130 mm S-26, which was designated the S-26-1. It had practically the same ballistics as the BL-9, but it had a muzzle brake, different components, and the chassis used a different mantlet. It could fire 1.5-1.8 rounds per minute, and had a muzzle velocity of 1000 m/s. It underwent field tests in November, 1944, but according to sources, something (probably the mantlet or gun mechanism) was simply not strong enough to withstand firing the gun. The gun project was totally completed in June, 1945, but was abandoned due to the war’s end.
Photograph of an ISU-122-3. Its muzzle brake is very distinguishable, compared to the ISU-122-1, which featured a similar length gun, but no muzzle brake
Photograph of an ISU-122-3. Its muzzle brake is very distinguishable, compared to the ISU-122-1, which featured a similar length gun, but no muzzle brake.
Another supposed ISU-130 name is scarcely referred to in Zaloga’s “Soviet Tanks and Combat Vehicles of World War Two“. According to the book, it was a design that came about towards to the end of the war by Dukhov’s team. It was either an ISU-122 or IS-3 chassis (he later contradicts himself, but the drawing certainly appears to show an IS-2/ISU-122 chassis) with a 130 mm naval gun. It was not produced until after the war, and strongly resembled the Object 704. It is more than likely that this was a version of the above, and due to the lack of access to Kremlin archives at the book’s publication date, it is probably an inaccurate story and depiction.
Drawing of an
Drawing of an “ISU-130” as taken from Zaloga’s “Soviet Tanks and Combat Vehicles of World War Two”. It closely resembles the Object 704, and appears to be based on an IS-2/ISU-122. Due to the lack of access to Kremlin archives at the book’s publication date, it is probably an inaccurate depiction.

isu-122 camo
An ISU-122 with winter camouflage, Germany, 1945.

The ISU-122 in action

The ISU-122 was a multi-role tank, much like the ISU-152. However, it had the advantage of a fairly accurate gun, with excellent AT capabilities. At a range of 1000 m, the ISU-152 could penetrate 120 mm (4.72 in) of armor (which was the Tiger’s maximum armor thickness), but the ISU-122 could penetrate 160 mm (6.3 in) (which is much closer to the King Tiger’s 185 mm/7.28 in maximum armor thickness), and was more accurate.
Whilst the ISU-122 tended to use armor piercing rounds, due to supply issues, they often found themselves firing high-explosive shells designated OF-471. These shells weighed 25 kilograms, had a muzzle velocity of 800 m/s, and had a 3 kilogram TNT charge. This proved absolutely excellent for AT duties as the explosion and shock-wave sent across the mechanisms on the targeted tank were sometimes enough to knock it out even without penetrating!
However, its AT capabilities were rarely taken advantage of due to the tactics used by heavy SPG regiments. It was used, like the ISU-152, for direct fire, and there was no practical distinction between the ISU-152 and ISU-122 at the time.
An ISU-122 in Gdansk, Poland, 1944
An ISU-122 in Gdansk, Poland, 1944.
Many ISU-122s were often fielded in mixed units with the ISU-152, despite attempts by Red Army Commanders to avoid this within one tank regiment or at least a tank brigade. There were two main reasons for this – the first being that two sets of calculations would be needed for indirect fire orders, and the second being that the tanks took different ammunition types, which would cause supply problems as two different shell types would need transporting.
Aside from that minor problem, the ISU-122 fared very well in combat. Being based on the IS-2 hull, it had excellent armor performance, which was previously a problem for many Soviet SPGs, such as the SU-76 and SU-85, which would not be able to handle much attention from enemy armor or AT guns.
An ISU-122S in Czechoslovakia. The D-25S' muzzle is covered up, but still distinguishable
An ISU-122S in Czechoslovakia. The D-25S’ muzzle is covered up, but still distinguishable.
Duties as a self-propelled howitzer with indirect fire were rare, but not unheard of. This was usually done during quick advances, when support from field artillery was not available. The gun had a maximum range of 14 km, which made it a viable role to take on, but it was simply not a common tactic.
In urban combat, the ISU-122 fared marginally less well than the ISU-152 for two reasons – first, the longer gun barrel made traversing difficult in small, rubble filled streets, whereas the ISU-152, with its smaller gun, did not have this problem. Secondly, the smaller, 25 kg HE shell, was not as destructive as the shells fired from the ISU-152. The ISU-152 was given a 43.56 kg HE shell, a 48.78 kg AP shell, and even a 56 kg long range, concrete-piercing shell which could obliterate enemy positions.
As mentioned earlier, the ISU-122 only had AP and HE shells, which were less destructive and therefore not as effective as the ISU-152. Despite this, it was viewed as a good urban assault gun (again, there was practically no distinction between the ISU-122 and ISU-152 by Red Army Command), and HE shells were usually sufficient at taking out enemy pillboxes, fortified buildings, and trenches. Even considering that the ISU-122’s shells were not as destructive, it must be remembered that the ISU-122 had just over twice the rate of fire than the ISU-152, even without experienced loaders.
After the war, most ISU-122s survived, although many were, as mentioned, scrapped, or converted in the 1950s and 1960s. Despite those programs, some are still preserved today and at least five stand in museums across Eastern Europe. Many others are preserved as memorials.

ISU-122 in Chinese service

Once the Red Army left Dailan, Liaoning Province, in former Manchuria, all weapons from that area were sold to the People’s Liberation Army. An unknown number of ISU-122 tanks (according to an available photo of a parade, at very least, six) were sold to the People’s Republic of China, along with SU-76s, ISU-152s, T-34/85s, T-34/76s, SU-100s, and SU-76s. It is unknown if any ISU-122S tanks were sold along with these.
An ISU-122S at Konigsberg
An ISU-122S at Konigsberg.
An ISU-122S crosses a pontoon bridge
An ISU-122S crosses a pontoon bridge.
ISU-122 of the 59th Independent Breakthrough Tank Regiment, 9th Mechanized Corps, 3rd Guards Tank Army, in a strange winter livery, Ukrainian SSR, 1944
ISU-122 of the 59th Independent Breakthrough Tank Regiment, 9th Mechanized Corps, 3rd Guards Tank Army, in a strange winter livery, Ukrainian SSR, 1944.
A column of ISU-122s, notice that the A-19S gun does not feature a double-baffle muzzle brake and has a heavier gun mantlet
A column of ISU-122s, notice that the A-19S gun does not feature a double-baffle muzzle brake and has a heavier gun mantlet.
An ISU-122 and an IS-2 pass through Transylvania, 3rd Ukrainian Front, 1944
An ISU-122 and an IS-2 pass through Transylvania, 3rd Ukrainian Front, 1944.

An ISU-122 passes through a parade in Lodz, Poland, 1945
An ISU-122 passes through a parade in Lodz, Poland, 1945.

ISU-122 specifications

Dimensions (L-w-h) 9.85 x 3.07 x 2.48 m (32.3 x 10 x 8.1 ft)
Total weight, battle ready 45.5 tonnes
Crew 4 or 5 Commander, Gunner, Driver, Loader and an optional second loader)
Propulsion 12 cyl. 4 stroke diesel, V-2IS 520 hp
Speed (road) 37 km/h (23 mph)
Range 220km (137 miles)
Armament 122 mm (4.8 in) A-19S tank gun (ISU-122) or 122 mm (4.8 in) D-25S (ISU-122S)
DShK 12.7 mm (0.3 in) AA machine-gun (250 rounds)
Armor 30-90 mm, plus 120 mm mantlet (1.18-3.54 +4.72 in)
Total production 2410 (1735 ISU-122, 675 ISU-122S), 1944-1945. Possibly at least 1000 more 1947-1952, although sources give wildly varying different figures.

An article by Will Kerrs

Sources

Russian Tanks of World War II, Stalin’s Armoured Might“, by Tim Bean and Will Fowler.
Soviet Tanks and Combat Vehicles of World War Two” by Steven J. Zaloga and James Grandsen.
IS-2 Heavy Tank 1944-1973” by Steven J. Zaloga
ftr.wot-news.com
russian-tanks.com
tankarchives.blogspot.co.uk
www.ww2incolor.com
russianarmor.wikia.com
www.las-arms.ru
Photographs: Wikipedia.
ww2 soviet armour
All ww2 Soviet Tanks Posters

ISU-122, summer, 1944
ISU-122, summer, 1944
ISU-122, unknown unit, east Prussia, 1944
ISU-122, unknown unit, east Prussia, 1944
ISU-122, unknown unit, Germany, 1945
ISU-122, unknown unit, Germany, 1945
ISU-122, winter camouflage, Germany, 1944-45
ISU-122, winter camouflage, Germany, 1944-45
ISU-122 camouflaged, unknown unit, 1944
ISU-122 camouflaged, unknown unit, 1944
ISU-122, 338th Guards Kirovgradarsky heavy self propelled regiment, 1945
ISU-122, 338th Guards Kirovgradarsky heavy self propelled regiment, 1945
ISU-122S, unknown unit, Poland, summer, 1944
ISU-122S, unknown unit, Poland, summer, 1944
ISU-122S
ISU-122S
ISU-122S, Berlin, April, 1945
ISU-122S, Berlin, April, 1945
ISU-122S, Hungary, March, 1945
ISU-122S, Hungary, March, 1945

ISU-122 of the People’s Liberation Army, on parade in Beijing, 1954.
BTT-1 heavy duty armoured recovery vehicle after the war. Many were resold to the Egyptian Army, well into service in the 1980s.
BTT-1 heavy duty armoured recovery vehicle after the war. Many were resold to the Egyptian Army, well into service in the 1980s.

Categories
WWII Soviet SPGs

ISU-152

Soviet Union Soviet Union (1943-1947) Heavy Self-Propelled Gun – 4635 built

A 152 mm “beast killer”

The ISU-152 was an absolute nightmare for the Wehrmacht. Much like the SU-152, it was capable of blowing Tiger, Ferdinand, and Panther turrets/casemates open. However, what made the ISU-152 inherently better than the SU-152 was its superior armor and towing power. It had three major roles – assault gun, tank destroyer and mobile artillery, which made it one of the most versatile heavy vehicles of the war. After the war, it remained in service well until the 1970s, and some even saw some unconventional action at the Chernobyl liquidation, 1986.
A very dramatic photo of a pair of ISU-152s fording a river
A very dramatic photo of a pair of ISU-152s fording a river.

Design process

The ISU-152 came about for two main reasons – the success of the SU-152, and the arrival of the IS heavy tank hull. Seeing as though the IS was an upgrade of the KV series, which the SU-152 was based on, it made perfect sense to mount the same weapons on the newer platform. This would mean that maintenance would be easier, with a sort-of standardization of late war tanks. Shortly after the SU-152’s deployment, the NKTP (Ministry of Transport Machine-Building Industry) ordered design teams in Chelyabinsk, in cooperation with the Mechanized Artillery Bureau, and General F. Petrov, to design two new heavy assault guns based on the IS-2 hull on May 25th, 1943. The development for this tank was undertaken by the famous Joseph Kotin, and G.N. Moskvin as the main designer – the first prototype was ready in only a month.
The first prototype, known as the IS-152, was similar to the SU-152, except for a higher superstructure that was more rectangular, and also featured less sloped side armor. Thicker frontal and side armor (90 mm instead of 60 mm) did not make the crew compartment any smaller, so there was still space for 20 shells for the ML-20S gun. The other main differences between the SU-152 and the IS-152 were that the suspension was lower, and a heavy, two-piece gun mantlet was bolted onto the right of the hull. It underwent factory trials in September, 1943, but a large number of problems with the design was encountered, so the design was reworked.

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Finally, the second vehicle, designated the Object 241, was ready in October, and it began factory trials, shortly followed by state trials at Gorohovestskom test range. By November 6th, 1943, an order was issued for this tank to be mass produced and it was now known as the ISU-152. Production started in December and replaced production of the SU-152 at the Chelyabinsk Kirovsk Plant.
The ISU-152 was hardly a different concept to other Soviet self-propelled guns. It still featured two compartments – the fighting compartment and ammo storage in the front, and engine and transmission at the back. The gun was mounted slightly off-center and could traverse 12 degrees left and right. It had 12 torsion bars, 6 road wheels, rear drive sprockets, and front idlers identical to road wheels, thus making maintenance easier. There were three internal fuel tanks – one in the rear compartment, and two in the fighting compartment. Like most late-war Soviet tanks, there were also up to four external fuel tanks that were not connected to the engine.
The crew of an ISU-152 appear to be cleaning their boots with Nazi banners
The crew of an ISU-152 appear to be cleaning their boots with Nazi banners.
All roof hatches were fitted with periscopes, as well as there being two gun sights – a telescopic, and a panoramic ST-10. An intercom was also fitted, and each vehicle had a standard 10R or 10RK radio set. The crew was also given a pair of PPSh-41 sub-machine guns with up to 1491 rounds, as well as 20 F-1 grenades in case they needed to abandon the vehicle in combat. Giving the crew weapons was not at all an uncommon practice. Whilst at first, the ISU was based on the IS-1 hull, it was later based on the IS-2 hull in 1944, which meant that the vehicle had extra fuel capacity, a newer radio, a slightly modernized main gun, mantlet armor was increased, and finally, an AA machine gun was installed in an AA mount. Also, a fourth, round hatch was fitted at the top right of the roof, next to the rectangular hatch on the left-hand side. The later ISU-152 modifications, with newer gun and slightly longer barrel, (4.9 meters), had a maximum range of fire of up to 13,000 meters. Between December 1943 and May 1945, 1885 ISU-152s were made. When production finally ended in 1947, 3242 vehicles had been produced, although some sources give wildly varying figures for total production.
An ISU-152 at Yad la-Shiryon museum, Israel. On the right is a BTT-1 recovery vehicle which was converted from the ISU chassis, after having its main gun removed
An ISU-152 at Yad la-Shiryon museum, Israel. On the right is a BTT-1 recovery vehicle which was converted from the ISU chassis, after having its main gun removed.

Variants

ISU-152 M1945 (Object 704)

One prototype was developed using ideas from the IS-2 and IS-3 in 1945. It was fitted with a modernized ML-20SM mod.1944 gun-howitzer, which was 4.5 m long. Muzzle velocity firing the 48.78 kg HE shells was 655 m/s and the tank could fire 1-2 rounds per minute. It featured four hatches, as well as one emergency hatch below the driver’s seat. It also had two 12.7 x 108mm DShK machine guns, one as coaxial and one in an AA mount. Armour thickness at the front of the gun was 320 mm (12.6 in) thick, combining the hull with the mantlet, making it one of the best protected vehicles of the era. However, the extreme armor angle and the increased gun recoil meant that the crew had substantially worse working conditions and for this reason, it was never adopted.
Object 704 at the Kubinka museum
Object 704 at the Kubinka museum.

ISU-152K

This was a modernized variant from 1956, undertaken at the Leningrad Kirov Plant and designated the Object 241K. It took a new engine, the same as the T-54 and the main, internal fuel tank now had a capacity of 920 L, giving it 500 km more operational range. It had ammo capacity for another 10 shells, now giving it a grand total of 30 shells, due to an additional fuel tank in the crew compartment being removed. The commander’s cupola and sights were reworked and improved. It was also given a new running gear design based on the T-10 heavy tank. The mantlet was given an additional armor ring – some even had 15 mm extra welded onto the 60 mm mantlet from above.

ISU-152M

This was the last modernization that the ISU would face and it was undertaken in 1959 at the Chelyabinsk Kirvosk Plant, ‘the birthplace of the ISU’. It was much the same as the IS-2M modernization at this time, and the upgraded vehicles were designated the Object 241M. It featured all the same upgrades as the ISU-152K, except they were given night vision sights, more ammunition for the new DShKM machine guns, but they were not given a new cooling system for the new engine.
A pair of ISU-152Ms are landed from
A pair of ISU-152Ms are landed from “Voronezhskiy Komsomolets”, a Tapir Class Landing Ship (NATO Reporting Name: Alligator), some time in the late 1960s.

“ISU-152BM” (Object 246 and 247)

In August 1944, there was a need to create a tank that could directly and easily knock out the heaviest German tanks, such as the Jagdtiger and King Tiger. This led to the attempt to build a longer barreled 122 mm gun on the IS-2 and ISU-122, as well as a longer barreled 152 mm gun on the ISU-152.
The first, the Object 246 (ISU-152-1), featured the BL-8 gun. It had a maximum range of 18,500 m with a muzzle velocity of 880 m/s with its 43.56 kg HE shell. The gun itself was eight meters long! During testing, it was discovered that it could penetrate 203 mm of armor at 90 degrees from up to 2000 m away. However, whilst this sounds excellent, trials in December 1944 showed that the crew found operating the gun difficult, the muzzle brake and breech block were unreliable, the barrel strength and angle of horizontal guidance were unsatisfactory, and finally, the very long gun would limit the maneuverability of the vehicle, much like the D-25 on the ISU-122 limited its maneuverability.
A second prototype was reportedly made in August 1944, the Object 247 (ISU-152-2). It fitted the improved BL-10 gun, which had a maximum range of 18,500 m firing a 43.56 kg HE shell, featuring a muzzle velocity of 850 m/s with 3 rounds per minute. During testing, it was discovered that it could penetrate 203 mm of armor at 90 degrees from up to 2000 m away, but the barrel integrity and angle of horizontal guidance were poor. Another attempt at improving the gun was made, but the war ended before anything more than a test revealing that the new gun had a maximum range of 19,500 m and a muzzle velocity of 880 m/s. It was then deemed that there was no need for this work to continue, mostly because the war was over, and there was no need to combat heavily armored German vehicles.
Two similar projects were also made based on the ISU-122 chassis.
An ISU-152-1 with the BL-8 gun
An ISU-152-1 with the BL-8 gun.

Gallery

A Soviet tanker fires a DShK mounted on an ISU-152. Hungarian partisan stands guard near a knocked out ISU-152, 1956.An abandoned ISU-152 with the Chernobyl nuclear facility in the background. This tank is far too irradiated for further use.An ISU-152 knocks down a building at Chernobyl, 1984.152 mm shells being prepared and verifiedFinnish ISU-152Finnish troops prepare a captured ISU-152 for rail transport.This Iraqi ISU-152 was knocked out near Camp Fallujah by a coalition airstrike. The fighting compartment was blown off!A preserved Guards ISU-152K at Victory Park, Moscow, Russia.A knocked out ISU-152 in Berlin. The main gun has been shot by a Panzerfaust, and it appears as though the hull was hit by numerous rounds, too.Czech TSD-152s in paradeAnother ISU-152 during the Hungarian Uprising. A partisan inspects the driver’s viewport.Ukrainian ISU-152s, summer 1944

Video: Inside the Chieftain’s hatch

The ISU-152 in action

Most ISU-152 were often fielded in mixed units with the ISU-122, despite attempts by Red Army Commanders to segregate the two vehicles. There were two main reasons for this – the first being that two sets of calculations would be needed for indirect fire orders, and the second being that the tanks took different ammunition types, which would cause supply problems, as two sets of ammunition would need transporting.
The biggest let down for the ISU-152 was its ammunition capacity. It only had space for 20 shells, usually 13 HE and 7 AP or Concrete-Piercing, and possibly some stowed on the rear deck. It took up to 40 minutes to resupply ammunition and it needed a very strong loader, as each shell weighed over 40 kg. This would strongly affect combat capabilities, especially if supply lines were bogged down, or if an offensive lasted too long, meaning that the tank would run out of munitions far too quickly. Having said this, an experienced crew would make the best use of its limited ammunition and it would fare well.
Much like its older brother, the SU-152, the ISU-152 took on three major roles:

1. Tank Destroyer

Whilst not designed for this role, it inherited the name “Zveroboy” (Beast killer) from the SU-152, because it could knock out the Panther, Tiger, and King Tiger tanks, as well as the Jagdtiger, and Ferdinand/Elefant. It is actually well known for this role because the Soviets were able to make this into a very effective propaganda tool in the late war. Whilst the weight of the shells (and therefore slow loading) resulted in 1-3 rounds per minute, the sheer mechanical shock was enough to kill the crew of an enemy tank, or disable an enemy tank even without an armor penetration, which is useful because generally, these shells did not penetrate. It has even been reported that the shell could totally blow the turret off of a Tiger tank!
At Kursk, AP shells were given to the ISU-152, but these rounds were expensive, hard to make, and were in very short supply, as well as only being a little more effective than the HE round. Finally, when fired upon, the ISU-152’s 90mm, 90 degree sloped armor fared well against 75 mm German guns at long ranges, but the Tiger’s 88mm gun was always a killer. However, despite stories and amazing photos of the ISU-152’s exploits as a tank destroyer, at close ranges, it was vulnerable to German high caliber guns, and it had a low rate of fire. Not only this, but it was inaccurate, and not intended for the role. ISU-152s tended to be used for direct fire as an assault gun, which saw it fighting against enemy positions, not necessarily enemy tanks.
The result of an ISU-152 shell hitting a Panther’s turret. Instead of being knocked off, the turret was blown wide open!
The result of an ISU-152 shell hitting a Panther’s turret. Instead of being knocked off, the turret was blown wide open!
This Brummbar was reportedly hit by an ISU-152
This Brummbar was reportedly hit by an ISU-152.

2. Self-propelled Artillery

When field guns were in short supply, the ISU-152 was able to perform preparatory shelling to help out with Red Army advances. The Soviets never had any specialized, mass-produced vehicle for this purpose, but the ISU-152 was as close as they would get for the time being. Whilst towed artillery units were given to mechanized divisions, they were vulnerable and slow to field compared to the ISU-152. However, it must be remembered that in heavy SPG regiments, the tactics used for the ISU tanks were not indirect fire, but direct fire, making this role a rarity.

3. Assault gun

Assault gun was the main role taken on by the ISU-152. It was described as one of the most valuable weapons in urban areas like Budapest, Berlin, and Konigsberg. Its armor was, as mentioned, surprisingly excellent defense against German AT guns. The massive HE shells were perfect for taking out enemy fortified positions and buildings. Considering that using the conventional, towed ML-20 field gun would result in its crew being exposed, mounting the same gun in a tank negated that problem, and proved to have fantastic results. When supporting other tanks, the ISU-152 was always placed behind an IS, about 100-200 m behind, and it was usually second in the column.
The commander of an ISU-152 and other officers consult a map during WWII.
The commander of an ISU-152 and other officers consult a map during WWII.
Regiments using the ISU were formed as Independent Heavy Self-propelled Artillery Regiments, and between May 1943, and 1945, 53 of these regiments existed. In December 1944, Guards Heavy Self-propelled Artillery Brigades were formed which gave heavy fire support to tank armies, and fielded 65 ISU-152s or ISU-122s (sometimes combined, although, as mentioned, there were attempts to segregate the vehicle types). Many were reformed regiments, and used similar tactics to what they were used to, such as supporting infantry through direct fire. These regiments fielded trucks, jeeps, and motorcycles for support.
The biggest risk to the ISU-152 was posed by Panzerfaust-equipped infantry in urban combat. To combat this, they operated sometimes in pairs of tanks, but always with infantry, much like many tanks did in urban combat. The supporting infantry always had a specialized sniper (or marksman), sub-machine gunners, and sometimes a flamethrower. The heavy DShK machine gun on the ISU-152 was also excellent for killing Panzerfaust-wielding soldiers in upper floors or behind cover, as it had excellent stopping power. However, if these tactics were not strongly understood, the ISU’s less-well armored roof was vulnerable and this would be exploited by the enemy.
The ISU-152 would later be used in many maneuvers across the Eastern Bloc, and a small number were later sent to Hungary in 1956 to end the uprising. These were often knocked out due to the brutal street fighting and use of Molotov cocktails by Hungarian Partisans. It is known that a very small number of ISU-152s took part in the liquidation of the Chernobyl disaster, 1986. They were used to clear buildings by ramming them down, like a bulldozer. After they became too irradiated for use, many were either dumped in vehicle graveyards, or were just left where they were.

The ISU-152 in foreign service

Finnish ISU-152s

In 1944, two vehicles were captured. One was lost in fighting, the other never saw combat.

Polish ISU-152s

In 1944, 30 were given to the People’s Army of Poland. This led to the formation of the 25th Self-Propelled Artillery Regiment with 10 ISU-152s and 22 ISU-122s. It was fielded with the Polish 1st tank corps (which had T-34/76s, and T-34/85s) and fought in south-west Poland. The later, 13th Self-Propelled Artillery Regiment, with two ISU-152s, took part in the Berlin offensive. They remained in service until 1962.

Chinese PLA ISU-152s

Once the Red Army left Dailan, Liaoning Province, in former Manchuria, all weapons from that area were sold to the People’s Liberation Army, including 67 ISU-152s, which later formed the 1st Mechanical Division.
A pair of Chinese ISU-152s at the CPLA tank museum
A pair of Chinese ISU-152s at the CPLA tank museum.

Czechoslovakian TSD-152s

Some ISU-152s were given after WWII and remained in service until the late 1950s with the Czechoslovakian Army, designated locally TSD-152.
Czechslovakian TLD-152s
A column of Czechoslovakian TSD-152s.

Romanian ISU-152s

Some ISU-152s were given to the 6th, 7th, and 57th Tank Divisions in the 1950s.

North Korean ISU-152s

An unknown number were used during and after the Korean war. They were most likely sold to them by the PRC.
An Egyptian ISU-152 during the 1973 war, it is being used as self-propelled artillery, and has been given a desert camouflage.
An Egyptian ISU-152 during the 1973 war, it is being used as self-propelled artillery, and has been given a desert camouflage.

Egyptian ISU-152s

As a result of the growing relationship between the USSR and Egypt in the mid-20th century, Egypt received (or more likely, bought) at least “one regiment” from the USSR in the early 60s, and these ISU-152s (and ISU-122 chassis based BTT-1 recovery vehicles) were used during the 1967 and 1973 Egypt-Israel wars. At least one captured ISU-152 stands in Yad la-Shiryon museum, Israel.

Yugoslavian ISU-152s

One ISU-152 was abandoned by the Red Army’s 2nd Ukrainian Front because it was stuck in the mud near Pancevo Bridge. In 1946, it was salvaged and was used at the Tank School at Bela Crkva (in modern day Serbia), having fitted it with a T-34’s engine. It was later used as target practice at the Manjaca range.

Iraqi ISU-152s

A small number of ISU-152s were used by Iraq during the Iran-Iraq War and First Gulf War. It is unclear how these were obtained, but it is likely that they were sold by the USSR or PRC. They might have been captured during the Iran-Iraq War, but this is speculation only.

ISU-152 specification

Dimensions (L-w-h) 9.18 x 3.07 x 2.48 m (30.1 x 10.1 x 8.1 ft)
Total weight, battle ready 47.3 tonnes
Crew 4 or 5 (Commander, Gunner, Driver, Loader and an optional second loader)
Propulsion 12 cyl. 4 stroke diesel, V-2IS 520 hp
Speed (road/off-road) 30, 15-20 km/h (19 mph, 9-12 mph)
Range Up to 220 km (137 miles)
Armament 152.4 mm (6 in) ML-20S gun howitzer (20 rounds)
DhSK 12.7 mm HMG roof (0.5 in), 250 rounds
Armor 90-120 mm (3.5 – 4.7in)
Total production 4635

Links and Sources

The ISU-152 on Wikipedia
Russian Tanks of World War II, Stalin’s Armoured Might“, by Tim Bean and Will Fowler.
Soviet Tanks and Combat Vehicles of World War Two” by Steven J. Zaloga and James Grandsen.
IS-2 Heavy Tank 1944-1973” by Steven J. Zaloga
Photographs: Wikipedia.
ww2 soviet armour
ww2 Soviet Tanks Poster

Early production ISU-152, summer 1944
Early production, summer 1944ISU-152 of the Red Guards, summer 1944, Bagration offensive
ISU-152 of the Red Guards, summer 1944, Bagration offensive.Camouflaged ISU-152 of the Lviv regiment in Ukraine, July 1944
Camouflaged ISU-152 of the Lviv regiment in Ukraine, July 1944
Finnish ISU-152. Two were captured in the summer of 1944.
Finnish ISU-152. Two were captured in the summer of 1944.
ISU-152 of an unknown unit, Germany, 1945
Unknown unit, Germany, 1945.
ISU-152 of an unknown unit, Germany, 1945.
Unknown unit, Germany, 1945.
ISU-152 of an unknown unit, winter 1944-45
Unknown unit, winter 1944-45. Notice the camouflage improvised on the washable white paint
Unknown unit, winter 1944-45
Unknown unit, winter 1944-45, “Moskva”
ISU-152 of the 7th Independent Guards Heavy Tank Battalion
ISU-152 of the 7th Independent Guards Heavy Tank Battalion, Berlin 1945.
ISU-152 participating in the offensive on Berlin, April 1945
ISU-152 participating in the offensive on Berlin, April 1945. Notice the typical reconnaissance white bands.
Polish ISU-152M, 1960
Polish ISU-152M, 1960.
Egyptian ISU-152
Egyptian ISU-152, war of 1973 (Yom Kippur).
Iraqi ISU-152
Iraqi ISU-152. Several were still in use during the war of 1993, as mobile artillery support.
Chinese ISU-152
Chinese ISU-152 in the 1950s. This one preserved at the CPLA tank museum.
Categories
WWII Soviet SPGs

KV-2

Soviet Union Soviet Union (1940-1941) Heavy Assault Tank – 203 built

The bunker-buster

The Russo-Finnish war proved the soundness of the decision to manufacture the KV-1. However, when encountering difficulties on the heavily fortified Mannerheim line during the Winter War in Finland, the General Staff demanded a specially equipped version fitted with a heavy howitzer, intended to deal with concrete bunkers, in support of the regular KV-1 units. Instead of choosing the more pragmatic solution of a traditional SPG, they decided to use the same turret ring to accommodate a fully traversed, redesigned turret that housed the gargantuan howitzer. This gave the KV-2 an unmistakable profile, with its towering turret, which was only accessible by a ladder – an obvious target which was also notably top-heavy, compromising the lateral stability of the tank while crossing a sloped terrain, a problem which would later haunt Soviet tank crews. All these deficiencies were taken into account when the factory was relocated in the new “Tankograd” complex at the steps of the Ural. However, production was no longer maintained. Only 203 were built in all from late 1939 to mid-1941.

Design process

The North-West front headquarters and the Commander of the Seventh Army, Kiril Meretskov, made forceful requests for a bunker-busting heavy tank. Several projects were then undertaken. In one of their last projects before disbandment, the OKMO team revived the T-100 hull and mounted a B-13 130 mm (5.12 in) naval gun, designating it the SU-100Y. However, this was rejected because of the army’s lack of barrels and naval semi-armor piercing rounds, at a time when the Soviet Navy was beginning a massive expansion in order to create a more powerful, ocean-going fleet. Somewhat more pragmatically, Zhozef Kotin’s team, at the Kirov Plant in Leningrad, developed two designs based on the already battle-proven KV chassis, which made more sense in terms of streamlining production costs. There was an initial attempt to mount a 152 mm (5.98 in) BR-2 and a 203 mm (8 in) B-4 howitzer on a lengthened KV hull, but this was never completed.


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The third design was the design which was chosen. Completed in two weeks, it had a 152 mm (5.98 in) howitzer with two DT machine guns mounted on an unmodified KV chassis. It was accepted for production and designated the KV-2. First trials were conducted on 10th February, 1940 and shortly after, two prototypes were sent to the front on the Karelian Isthmus. However, there is some debate as to whether these prototypes saw combat. Recent evidence suggests that Meretskov’s and others’ reports on the excellent results achieved by the KV-2 against fortified positions and pillboxes referred to tests conducted against already captured positions.
The KV-2 had one of the most unique silhouettes of WWII. The hull was no different to that of a KV-1, but in order to fit the 152 mm (5.98 in) L20 howitzer, a box shaped, 12.9 tonne turret was mounted. This now made the vehicle stand 4.9 m (16 ft) tall, compared to the 3.9 m (12.8 ft) height of the KV-1. However, the high profile of the KV-2’s turret was compensated by its immense armor – 110 mm (4.33 in) frontal armor and 75 mm (2.95 in) side armor.
In October 1941, KV-2 production was halted as Soviet factories relocated and were moved eastwards to avoid German capture.

Variants

Designation of the two models varies between sources and can be confusing. The earlier model of the KV-2 had a turret with a sloped front with rivets and only featured one DT machine gun in a hull mount. It weighed 53.8 tons, and was the lesser produced model. In German sources, this variant is referred to as the KW-II.  This model is sometimes erroneously called the KV-2 M1939 or KV-2 M1940. The turret is often wrongly called the MT-1, but that is the designation of the gun mount, not the turret. Sometimes the MT-10 designation is also wrongly used for the turret, and this seems like a mix of the mount name and the gun name (MT-1 + M-10). The turret was actually simply called “big turret” (большой башней).
The later variant of the KV-2 featured the more common and boxy turret, featuring a second DT machine gun in a rear mount, and an improved rear turret hatch that made resupplying ammunition easier. The armor was kept the same, but thanks to the removal of the angled turret front, it had a much roomier crew turret, meaning that working conditions were better for the crew, especially the loaders. In German sources, this variant is referred to as the KW-2B or KW-IIB. It is sometimes wrongly designated as the KV-2A, KV-2 M1940, KV-2 M1941 or KV-2B. The turret is often erroneously called the MT-2, seemingly as a progression over the wrong MT-1 designation of the previous turret. The turret was also simply called “reduced turret” (пониженная башня).
Very few early production models were fitted with the 122 mm (4.8 in) 1938 L/22.7 howitzer fitted to the earlier turret. The number produced is unknown, but were very limited before they were upgunned with the 152 mm (5.98 in) howitzer.
An unknown number of KV-2s were captured by the Wehrmacht. They were sent to Berlin for tests before they were fitted with a new commander’s cupola and sent back to the front line. These were designated (Sturm)Panzerkampfwagen KV-II 754(r) and were often used for artillery observation due to their height.
Perhaps the most interesting variant was a KV-2 armed with a 107 mm (4.21 in) gun. This was during a time when the superheavy tank concept was still being considered by Soviet leadership. There were no plans to serially produce a KV-2 with a 107 mm gun. Instead, just before the Siege of Leningrad, a KV-2 with a 107 mm gun was made and sent for fire testing in March, 1941. The 107 mm gun was going to be mounted on vehicles such as the KV-3, KV-4, and KV-5, but none of these projects left the drawing board as a result of the Siege of Leningrad. All 107 mm guns were destroyed and work on superheavy tanks was stopped.

The KV-2 in action

Due to its size and armored strength, it was nicknamed “Dreadnought” by its six man crews. The KV-2 first saw service in the Winter War as a prototype, as did many other vehicles. However, they were too late to test their might against the more fortified Finnish defenses, as they had already been overrun. Despite this, they still destroyed some remaining enemy bunkers and AT guns. Finnish AT guns were ill-prepared for the KV-2’s strong armor, and even reportedly stopped firing after three non-penetrations.
In the opening years of WWII, when the KV-2 operated in vast numbers, it was virtually invulnerable to direct fire from all but high velocity weapons at horrifically close-range. The best the enemy could hope to was force the KV-2’s crew to abandon the vehicle by disabling it, such as by hitting its tracks and wheels, but this did not always go to plan. A clear example of this was in June 1941, near Raseiniai. Roughly 20 KV tanks of the Soviet 3rd Mechanized Corps met the assault of the 6th Panzer Division, with approximately 100 vehicles. Another vehicle, probably a KV-2 tank, managed to hold off the German advance for a full day while being pummeled by a variety of antitank weapons, until finally the tank ran out of ammunition and was finally knocked out.
Having said this, the KV-2 paid a high price for its immense gun and vast armor. Its mobility between engagements and during battle was heavily restricted by many of the initial gear and transmission problems that the KV-1 faced. This situation was made even worse by the fact that the vehicle now weighed 53.8-57.9 tonnes depending on the model, as well as by using the unimproved 500 bhp V-2 diesel engine.
The road speed of a KV-2 was no more than 25 km/h (15.5 mph) and it only reached a mere 12 km/h (7.5 mph) off-road, making it a very slow moving vehicle. It was also prone to having trouble traversing the heavy turret if not on relatively flat ground. These problems all limited the flexibility of the KV-2 combat, but nevertheless, it was still a formidable opponent if dug into a strategic position. However, it lacked speed and mobility – two traits shown to be massively important in the opening years of the war.
The worst problem for the KV-2 was by far its unreliability. The gearbox would often break easily, and the immense recoil of the gun meant that the small turret ring could jam, or the engine or gearbox could suffer severe damage. The majority of KV-2 losses in 1941 were due to breakdowns or lack of fuel which forced them to be abandoned. The 41st Tank Division lost two thirds of its 33 KV-2s, but only five were as a result of enemy action – usually landmines, as there were few insufficient AT guns or enemy tanks capable of knocking out a KV-2, and as it was used as a breakthrough tank, the KV-2 would often be the first victim of mines.
Despite this, KV tanks came as a nasty shock to German invaders due to their resilience. They had no comparable tanks in strength, and few AT guns that could destroy them.
Marshal Rokossovsky later recalled in his memoirs, A Soldier’s Duty:
“They withstood the fire of every type of gun that the German tanks were armed with. But what a sight they were returning from combat. Their armor all pock-marked all over and sometimes even their barrels were pierced.”
Similarly, the experience of the 1st Panzer Division on 23rd June, 1941 in Lithuania proves just how resilient the KV-2 could be. Here is a record of the engagement:
“Our companies opened fire from 700 m (765 yd). We got closer and closer… Soon we were only about 50-100 m (55-110 yd) from each other. A fantastic engagement opened up – without any German progress. The Soviet tanks continued their advance and our armor-piercing projectiles simply bounced off. The Soviet tanks withstood point-blank fire from both our 50 mm (1.97 in) and 75 mm (2.95 in) guns. A KV-2 was hit more than 70 times and not a single round penetrated. A very few Soviet tanks were immobilized and eventually destroyed as we managed to shoot at their tracks, and then brought up artillery to hammer them at close range. It was then attacked at close range with satchel charges.”

Links

The KV-1 (generic) on Wikipedia

KV-2 specifications

Dimensions (L-w-h) 7.31 x 3.49 x 3.93 m (23ft 11in x 11ft 5in x 12ft 1in)
Total weight, battle ready 53.8 (early), 57.9 (late) tonnes
Crew 5– later 6 (driver, commander, gunner, 2 loaders)
Propulsion V-2 diesel, 500 bhp
Speed (road/off-road) 25/12 km/h (15.5/7.5 mph)
Range 200 km (120 mi)
Armament 152 mm (5.98 in) 1938/1940 L20 howitzer or 152 mm M-10T (later models)
2 x DT 7.62 mm (0.3 in) machine-guns (8000 rounds)
Armor 75-110 mm (2.95 – 4.3 in)
Total production 203

KV-2, model 1939, 3rd Regiment of the 2nd Tank Division, Central front, summer 1941. The KV-2 was globally an impressive but unsatisfactory model
KV-2, pre-production turret, 3rd Regiment of the 2nd Tank Division, Central front, summer 1941. The KV-2 was globally an impressive but unsatisfactory model.
KV-2 model 1939, unknown unit, winter livery, Leningrad sector, December 1941.
KV-2 in fictional livery. In reality, none are known to be painted with patriotic slogans.
PzKpfw KW II 754(r), Panzerkompanie (z.b.v.) 66, Malta invasion force, 1941. Notice the Panzer III commander cupola and headlight
PzKpfw KW II 754(r), Panzerkompanie (z.b.v.) 66, Malta invasion force, 1941. Notice the Panzer III commander cupola and headlight.

Gallery

Blueprints of the KV-2, U-3 preseries prototype
Blueprints of the KV-2, U-3 preseries prototype.
A technical drawing of the KV-2.
A technical drawing of the KV-2.
A KV-2 of the 2nd Tank Division/3rd Mechanised Corps being inspected by Germans. Notice the numerous 37 mm (1.46 in) AT shells that bounced off the turret. Baltic area, June 1941, suspected to be the infamous Raseiniai KV!
A KV-2 of the 2nd Tank Division/3rd Mechanised Corps being inspected by Germans. Notice the numerous 37 mm (1.46 in) AT shells that bounced off the turret. Baltic area, June 1941, suspected to be the infamous Raseiniai KV!
KV-2 displayed at the Central Museum of Russian Armed Forces, Moscow - Credits: Wikipedia.
KV-2 displayed at the Central Museum of Russian Armed Forces, Moscow – Credits: Wikipedia.
The U-3, a KV-2 prototype, February, 1940.
The U-3, a KV-2 prototype, February, 1940.
A KV-2 with a 107 mm gun. The KV-2 was similar to some superheavy tank projects the gun was intended for use with
A KV-2 with a 107 mm gun. The KV-2 was similar to some superheavy tank projects the gun was intended for use with.
KV-2Another destroyed KV-2A child next to the KV-2Another view of the KV-2 armed with the 107 mm gun
ww2 soviet armour
ww2 Soviet Tanks Poster