The IS Tank (IS in Cyrillic "ИС", meaning the Joseph Stalin or Iosif Stalin in Cyrillic "Ио́сиф Ста́лин") was a series of heavy tanks developed as a successor to the KV-series by the Soviet Union during World War II. It was named after Soviet leader Joseph Stalin. The heavy tank was designed with thick armour to counter the German 88 mm guns, and carried a main gun that was capable of defeating the German Tiger and Panther tanks. It was mainly a breakthrough tank, firing a heavy high-explosive shell that was useful against entrenchments and bunkers. The IS-2 was put into service in April 1944, and was used as a spearhead in the Battle of Berlin by the Red Army in the final drive to Berlin.
The IS-3 (Object 703) was developed in late 1944 by ChTZ (in Chelyabinsk) and left the factory shop in May 1945.This tank had an improved armour layout, and a semi-hemispherical cast turret (resembling an overturned soup bowl) which became the hallmark of post-war Soviet tanks. While this low, hemispherical turret improved protection, it also significantly diminished the working headroom, especially for the loader. The low turret also limited the maximum depression of the main gun (the A-19 122 mm field gun cannon), since the gun breech had little room inside the turret to pivot on its vertical axis. As a result, the IS-3 was less able to take advantage of hull-down positions than Western tanks. It weighed slightly less and stood 30 centimetres (12 in) lower than previous versions.
IS-3 Stalin Tank in The Hot WarEdit
IS-3s continued to be used at the spear-point as the invasion progressed but needed infantry support to operate with relative safety in the densely populated and close lying cities of Germany. While the hardest Soviet tank to kill, they were still vulnerable to bazookas or grenades through open hatches. Gustav Hozzel managed to kill a Stalin in Dortmund by throwing a Molotov cocktail through the open cupola hatch as its commander stood head and shoulders outside.