Throughout the Second World War, the German Army captured hundreds of tanks and armored vehicles from countries it invaded. The same was true during the invasion of the Soviet Union. The Germans frequently made upgrades and modifications to fit their needs. This process spawned one of the larger armored vehicle enigmas to come out of the War.
This was the KV-1 that was captured and then re-armed with the 7.5cm KwK 40 gun. Not much is known about the history of this improvisation, and there is only one known photo to prove its existence.
It is not the only tank of the Second World War that was retrofitted in the field to accept a gun from another nation. Other examples include the Churchill NA 75 which was a British Churchill tank modified to accept the American 75mm Tank Gun and the Matilda II that was modified to accept the 76mm ZiS-5 gun. In both of these cases, of course, they were not captured vehicles.
The only known image of the modified KV-1.
Background, the KV-1
The KV-1 was the unsuspecting winner of a Soviet contract for a new heavy tank to replace the obsolete T-35A Multi Turreted Heavy Tank. The KV tank beat the SMK and T-100 to make it to mass production. Immediately prior to the invasion of the USSR in June 1941, roughly 508 KV-1 tanks were in Red Army service.
The KV-1 was an unpleasant surprise to the advancing Germans in June 1941, due to its excellent armor protection. The KV-1 quickly gained a fearsome reputation on the battlefield, being able to withstand point-blank shots from the standard 37mm anti tank guns fielded by Germany. Many KV-1s returned from combat peppered with dents and gouges from ricochets which had failed to penetrate its armor. However, the KV-1s made little impact on the actual fighting during the months of Operation Barbarossa with the exception of a small number of engagements. Poor crew training, poor logistical support and inept command and control meant that the Soviet tanks, including the mighty KV-1, where deployed in small packets that were easily swallowed and terminated by the better organized German units.
The KV-1 tank weighed 45 tonnes, and was powered by the 660hp V2K engine. The suspension was the first Soviet use of torsion bars, and it consisted of six road wheels, a rear drive wheel, a large front idler wheel and three return rollers. The tank had a crew of five. Soviet engineers constantly updated the tank and, between 1941 and 1942, the armor was thickened from 90mm to 200mm in places. The firepower was improved too, from the 30.2 calibre long F-32 76.2mm gun, to the 42.5 calibre long 76.2mm Zis-5 gun. The F-32 gun could penetrate 50mm of armor at 1,000m, whereas the Zis-5 gun could penetrate 60mm of armor at the same range. In 1942, this made the gun a significant threat to most German tanks. However, the gun was similar to the one on the T-34 medium tank, which was far more mobile and far cheaper to build.
KVs in German Service
When the Wehrmacht first encountered the KV-1, they were horrified and greatly impressed with its capability to take extreme punishment from the main German tank and anti-tank guns of the time. Contrary to popular belief, there were only a handful of KV-1 tanks that were ever pressed into German service. The captured tanks were known as ‘Beutepanzer’ or trophy tanks.
In 1941, the Germans had a categorizing system for those units captured from the enemy, this was an “Ebeuten” number. The number for KV tanks of all sub-types was “E I”. The overwhelming majority of these tanks were either dismantled at the roadside, or returned to the Reich for museums or testing. However, there were some KV tanks pressed into Wehrmacht service.
Beutepanzer KV-1 ‘1’ of the of the 8th Panzer Division. Photo: SOURCE
The earliest known Beutepanzer KV-1s, which in the German numbering system were known as the Pz.KpfW KV-1a 753 (r) (r = Russia) were deployed in the Autumn of 1941. German changes were minimal, with most Beutepanzer KV-1s retaining the original Soviet radio and equipment, however, occasionally German radios and tool sets were issued. The most interesting German acquisitions were the two OKV-1 tanks pressed into service. The Kirov works in Leningrad had manufactured six prototype flame throwing KV tanks, with a flame unit in the hull. All were used in combat, and two were subsequently pressed into Wehrmacht service after their capture.
Between 1941 and 1943, the German army likely dealt with thousands of lost KV tanks, of which perhaps several hundred were captured in working condition. It is thought however that less than 50 KV-1 tanks were pressed into German service. A multitude of factors can explain this, from lack of spare parts, to German overconfidence in their own tanks, to the Nazi ideological doctrine that viewed anything manufactured by a Slavic race to be inferior.
The specific model of KV-1 that this conversion was based upon was a 1942 model, manufactured at Factory 100 Chelyabinsk (ChTZ) and was probably manufactured in the first or second quarter of 1942. It was fitted with the applique armor on the nose, and on the glacis plate which increased the armor up to 200mm (7.9 in) thick in places. It was equipped with the lightweight cast turret. Sometimes, this model also carried a heavyweight cast, or simplified welded turret. Standard armament remained the same, being the 76mm ZiS-5 gun. In German service, this was designated as the Pz.Kpfw KV-1B 755(r). This modified version was designated Pz.Kpfw KV-1B 756(r). The construction work was carried out by the maintenance battalion of Panzer Regiment 204 of the 22nd Panzer Division.
The most drastic modification to this single KV was the alteration made to the main armament. The original Soviet 76mm ZiS-5 gun was removed to make way for the German’s own 7.5cm KwK 40 L/43.
Diagram of the L/43 gun in its standard mounting, the Panzer IV
This gun was derived from the 7.5cm PaK 40, a towed anti-tank gun that entered service in 1942. In 1942-43, the gun was also mounted on Germany’s main medium tank, the Panzerkampfwagen IV, replacing the short barreled 7.5cm KwK 37 howitzer. Tanks with this new armament were designated as the Panzer IV Ausf.F2. It was a deadly weapon, with a range of ammunition types. These included Armour Piercing Capped Ballistic Cap (APCBC), Armor-Piercing Composite Rigid (APCR) and High-Explosive Anti-Tank (HEAT). The APCBC was its most deadly round, able to penetrate a maximum of 99mm (3.9 in) of armor.
At this time, the 7.5cm KwK L/43 was a rare gun, as only 135 Panzers were equipped with it. One these tanks must have been irreparably damaged in action, but retained an operable gun that was able to be cannibalized. Though the ZiS gun was removed, the mantlet was retained. The new gun was posted through the void breach first and mounted into position, complete with its coaxial MG 34 machine gun. It is unknown as to what internal modifications took place concerning the placement of the trunnions and elevation/depression gears. Being the more powerful gun, the KwK 40 was larger in the breach than the ZiS. The 7.5cm shell was 100mm longer than the 76mm shell of the ZiS, meaning the breach was also 100mm longer. Recoil length would also have been longer, meaning there was even less room behind the gun.
Minor modifications were also made to the turret. A salvaged commander’s cupola from either a Panzer III or Panzer IV (It is unclear which one it is) was added atop the turret. This was not added over the original commander’s hatch at the rear of the turret. A new hole was cut in the roof towards the right front of the turret, and the cupola added above it. This cupola gave the commander far better visibility, allowing him to spot targets, navigate terrain and observe friendly units easier.
On the left, an air filter was added, with a cover salvaged from a T-34.
A great deal of time was spent theorizing this matter by both authors of this article. The conversion of just this one vehicle would have been time and resource consuming. Other vehicles that were modified in such a way, such as the Churchill NA 75 and Matilda II with ZiS-5 which are mentioned in the introduction, had a designed purpose. The idea behind the Churchill NA 75 was to make use of guns from wrecked tanks, and give the poorly armed Churchill more Anti-Armor and High-Explosive firepower. The same was true for the Matilda, the original 2-Pounder gun of which was considered useless by the Soviets.
This KV, however, seems to lack any recorded intention. The German 7.5cm KwK 40 was a much better gun than the Soviet ZiS-5 76mm. At 1000 meters, the ZiS could only penetrate 61mm of armor, at the same distance, the 7.5cm could punch through 82mm. Ammunition may also have been a factor, as it would’ve been far easier for the Germans to resupply with 7.5cm ammunition than 76mm ammunition.
These are the only practical advantages of adding this gun to the KV. The KV, at this time, was one of the best heavy tanks in the war, and as already discussed, the Germans already had a number of captured examples in their arsenal. It may be that this was intended as somewhat of an ‘Anti-KV’ or ‘Anti-T-34’ vehicle. The Soviets’ own 76mm Gun could not penetrate the front of a standard KV-1 (without 200mm armor) or T-34 at 1000m. The German 7.5cm could handle both. Putting this gun on a chassis the 76mm could not penetrate would prove deadly to any Soviet vehicle facing it.
There is, however, an element of redundancy in the project worth highlighting. At the time this vehicle was built, German vehicles such as the Panzer IV (with long 75mm), Panzer V Panther, Panzer VI Tiger, and Panzerjager Tiger (P) were appearing. All of these, while still teething, were adequately armed so that the armor on the T-34 and KV-1 did not provide the advantage they had. With the 8.8cm gun or high velocity 7.5cm gun both the T34 and KV-1 were much more vulnerable.
The most logical conclusion as to why this KV was modified in this way is therefore that it was simply a culmination of spare parts and ingenuity.
This KV was apparently active at Kursk, but further details of this are scarce.
|Dimensions (L-w-h)||5.8 x 4.2 x 2.32 m (19.2×13.78×7.61 ft)|
|Total weight, battle ready||45 tonnes|
|Crew||4 (commander, driver, 2 gunners)|
|Propulsion||V12 diesel V2, 600 bhp (400 kW)|
|Maximum Speed||38 km/h (26 mph)|
|Range (road/off road)||200 km (140 mi)|
|Armament||7.5cm KwK 40 L/43|
2x DT 7.62 mm machine-guns 1x MG 34 7.92mm machine gun
|Armor||30 to 100 mm (1.18-3.93 in)|
Links, Resources & Further Reading
Panzer Tracts No.19-2 – Beutepanzer – British, American, Russian and Italian Tanks Captured From 1940 to 1945, Thomas L. Jentz & Werner Regenberg
Osprey Publishing, New Vanguard #17: KV-1 & 2 Heavy Tanks 1939-45
Frontline Illustrated, History of the KV Tank, Part 1, 1939-1941, M Kolomiets.
The Panzerkampfwagen KV-1B 756(r) with added 7.5cm KwK 40. Illustrated by Tank Enyclopedia’s own David Bocquelet.