This is not Russian propaganda
Iosif Stalin tank IS-2 tankWikipedia give this details
Specifications (IS-2 Model 1944[1])
Weight 46 tonnes
Length 9.90 m
Width 3.09 m
Height 2.73 m
Crew 4
Armor 30–160 mm
Primary
armament D25-T 122 mm gun (28 rds.)
Secondary
armament 2×DT, 1×DShK machine guns
Engine 12-cyl. diesel model V-2
600 hp (450 kW)
Power/weight 13 hp/tonne
Suspension torsion bar
Fuel capacity 820 l
Operational
range 240 km
Speed 37 km/h
Other material about IS-2
In January of 1944 the last 40 JS-85s were manufactured at the ChKZ. After this, it produced only the JS-122. These mounted the new 122 mm Tank Cannon D-25T with a wedge-shaped semi-automatic breech, which allowed an increased rate of fire from 1–1.5 shots per minute to 1.5–2 shots per minute. In March 1944, the «German-type» muzzle brake was replaced with a better design from the TsAKB. At the same time, the JS-85 was renamed JS-1, and the JS-122 was renamed JS-2.
At this stage, the issue of the JS-2's armament was not completely resolved. The military was not satisfied with its low rate of fire and limited ammunition stowage — only 28 two-piece rounds (compared to the 59 one-piece rounds for the JS-1 and 114 one-piece rounds for the KV-1S).
Further, after the first encounters between the JS-2 and German heavy tanks, it turned out that the sharp-nosed 122 mm APHE round — BR-471 — could only penetrate the frontal armour of a Panther up to 600–700 metres. The less powerful frontal armour of a Tiger could be penetrated at distances up to 1200 metres. However, at such distances only very well trained and experienced gunners could score a hit. The vertical armour of a Tiger I, although thicker than that of a Panther, was more easily defeated by the sharp-nosed projectile of the JS-2 Main Gun, whilst it often ricocheted off the sloped armour of a Panther. Later, Soviet designers noticed the blunt-nosed projectiles worked fine against sloped armour. After several tests, designers revealed the effect of «normalisation». The powerful HE round, OF-471, when fired at German tanks, caused cracking and could even completely tear off the front armour plate at the seam weld. The first results of the IS-2 in combat (backed by the results of its tests at the Kubinka testing grounds in January of 1944) forced designers to look for new solutions to its problems.
However, in the summer of 1944, the problem of the poor AP performance disappeared. The performance of the D-25T gun of the JS-2 against the German tanks improved dramatically. The reports from the front described cases where the BR-471 APHE round 122 mm projectile fired from 2500 metres ricocheted off the front armour of a Panther leaving huge holes and cracks in it.
This was explained by an interesting change of circumstances in the Summer of 1944. The Germans experienced a shortage of manganese and had to switch to using high-carbon steel alloyed with nickel, which made armour very brittle, especially at the seam welds. The first encounters of JS-2 tanks with the Germans also showed that the front protection of its hull was not impenetrable.
In the beginning of 1944, an attempt was made to improve the protection of the JS-2 by tempering the front armour to very high hardness. In practice, it led to a drastic increase in the number of components needed for the hull and significantly increased the cost of the tank's production.
In March 1944, firing tests were conducted with a 76.2 mm Gun ZiS-3 firing at an JS-2 tank from 500–600 metres. The tank's armour was penetrated from all sides of the tank. Whilst while most of the projectiles did not penetrate the armour completely, they created major splintering and fragmentation inside the turret. This explains the considerable losses of JS-85 and JS-122 tanks during the Winter-Spring of 1944.
In February of 1944 the Central Scientific Research Institute #40 (TsNII-40) was delegated the task of researching the armour protection of the JS-2 heavy tank. The research showed that, given the existing shape of the front of its hull, the tank would be invulnerable to penetration by any German 75-mm and 88-mm AP projectiles only if the hull's armour thickness were increased to at least 145-150mm (i.e. an addition of 20–30 mm thickness).
On the recommendation of the TsNII-40, new specifications for armour tempering and a new design for the front of the JS-2's hull were developed. The new hull, with a straightened glacis, preserved the same armour thickness while the plug-type driver's hatch was removed, greatly increasing its protection from the front. The glacis was sloped at 60 degrees from the vertical, which resulted in the German 88 mm KwK 36 gun being unable to penetrate it even at point-blank range when fired at a ±30 degrees angle.
However, the lower front hull armour plate, sloped at 30 degrees from the vertical, remained vulnerable. To increase its slope would require significant alteration to the layout and design of the driver's compartment. Since the probability of a hit on the lower part of the hull was low, it was decided to leave the design unchanged. From July 15 1944, spare tracks were attached to the lower hull to increase its protection. In May of 1944, the UZTM plant started manufacturing the new straightened welded hulls. Factory #200 began making the new type of hulls from June of 1944, but these were cast, not welded. However, for a while, tanks with old and new hull-types were produced simultaneously.
As for the tank's turret, it turned out to be impossible to increase its armour protection. Designed for the 85 mm gun, it was completely balanced. After installing the 122 mm weapon, the turret became very unbalanced. The Design Requirements intended for an increase of its frontal armour thickness to 130 mm which would have unbalanced the turret even further and would have made a new traverse mechanism necessary. SInce all these changes required a complete redesign of the turret, they were all cancelled.
Nevertheless, the appearance of the turret was considerably changed in the process of its production. The first batch of tanks manufactured in 1943 had a narrow porthole through which the sighting telescope fits. After the installation of the D-25T Main Gun, it became almost impossible to use the telescopic sight, even though its breech was the same as that of the D-5T.
Starting in May of 1944, a new turret with a widened porthole was manufactured, which resulted in the sight being moved to the left. The armour protection of the tank's mantlet was improved and the armour thickness of the sides of the lower hull was increased.
The commander's cupola was shifted 63 mm to the left and the PT4–17 periscopic sight was changed to a MK-IV sight. A DShK anti-aircraft machine gun (designer P. P. Isakov) was installed on the commander's cupola. After that, no further significant changes were made to the turret until the end of the war.
http://www.battlefield.ru/en/armors/28-heavy-tanks/32-js1-js2.html_____________________________________________________
It would be nice if IS-2 will have upgrade available.
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