The KV-2 was designed as a "bunker-buster", the need for which was discovered during the war against Finland in 1939. During this war, the high command issued that the Red Army had an urgent need for a heavy tank equipped with a more powerful armament to destroy the enemy fortifications (bunkers...). Four KV-1 were diverted to be tested with the heavy howitzer of 152 mm. They were the engineers of the KTZ which was charged to realize this conversion. After only two weeks, the project was finalized on paper. Initially it was the howitzer of 152 mm model 1909/1930 which was selected but the latter was quickly replaced by M-10 model 1938/1940, more modern. Of course, to accommodate this imposing weapon, a new turret (MT-1) was to be created. While it was an effective weapon versus static emplacements, its lumbering bulk was the complete opposite of what was needed during the mobile defensive battles of 1941, and it was quickly phased out of production. One prototype saw action in Finland in February 1940, around Summa. The KV-2's massive turret was difficult to traverse—especially if the tank was not on level ground.
At the beginning of 1941, the project was renamed KV-2. The imposing turret of the KV-2 was assembled on the hull of a KV tank experimental with double turrets. The first tests on this machine had been carried out on February 10, 1940. The tests on defense works were excellent and the KV-2 was thus accepted for the production. A total od 334 specimens of the KV-2 were produced in 1940-1941 in LKZ (Leningrad). Two models were created. The KV-1A (model 1940) had a too heavy turret which could be moved only on flat ground. The production of this model was abandoned end 1941. The KV-2B had a larger mantlet with a rounded shield. It weighed 4 tons more than model A and some were equipped with flame thrower. The KV-2B was carried out starting from the hull of the KV-1A. During the production, an additional machine-gun was installed.
The howitzer of 152 mm M-10 put at fire only high-explosive rounds of 52 kg (with reduced propellant charge) with a muzzle velocity of 436 m/s. The other ammunition of 152 mm were prohibited by the manual like the piercing or anti-concrete rounds. The KV-2 transported 36 rounds of 152 mm and 3087 rounds of 7.62 mm for its machine-guns DT (front hull, back of the turret). The crew of the KV-2 was composed of 6 men: the commander of the tank, the chief of shooting, the loader, the gunner, the driver and the radio-machine gunner. The four first with the howitzer were installed in the imposing (and very high) turret. To reach the trap doors on the roof , levels were laid out on the sides of the turret. This turret was not really a success, indeed, any traverse was impossible on soft and rough ground because of the weight and its height made KV-2 an easy target.
The KV-2 weighed 52 tons and was 7 m long. It had a 3.30 m height and a width of 3.25 m. It was propelled by a diesel engine V-12 V-2K developing 600 hp to 2000 rpm. It transported 600 L of diesel, which allowed him an autonomy on road of 250 km. Because of its weight, the KV-2 could hardly exceed the 26 km/h on road, which made a very slow vehicle of it. For the remainder, the design of the hull, respected that of the KV-1. The suspension always included 6 independent double-road wheels assembled on torsion bars, 3 double-return rollers, a front double-idler and a back double-sprocket-wheel. The tracks had a width of 650 mm.
On the level of the shielding of the hull, not change compared to the KV-1. For the turret made up of perfectly vertical walls, its thickness was of 75 mm. The mantlet had thickness a 110 mm and the roof a 40 mm thickness.
The KV-2 inherited the defects of design of the KV-1, in particular on the level of the transmission and the chassis. Let us add, a too heavy and not very handy turret , a too high silhouette making of him an easy target and one understands quickly that this model wasn't a great success. However, it created because of its imposing mass, a true agitation within the German tank crewmen at the time of its appearance on the battle fields in 1941. It should be said that in more of its impressive dimensions, this monster was safe from all the German anti-tank weapons of the time and only the anti-aircraft gun of 88 mm could bore its shielding.
The Germans of Panzer-Regiment 11, 6th Panzerdivision (Panzer-Gruppe 4), were the first to meet the KV-2 (2nd Russian armored division), June 25, 1941. They knew many difficulties vis-a-vis to these monsters however slow and badly designed. In fact the majority of the lost KV-2 were it because of engine and mechanic trouble or fuel shortage. In October 1941, the production of the KV-2 was abandoned.