The Russian IS-3 Heavy Tank was an upgraded IS-2 in late 1944. The IS-3 had improved armour layout, and a hemispherical cast turret. The turret offered a 30cm lower profile and cramped conditions for the crew and also restricted the elevation of the main gun, which limited its range whilst firing.
Starting in 1960, the IS-3 was slightly modernized as the IS-3M, in a manner similar to the IS-2M.
Firepower
The 122mm A19 main gun was an established field gun as a towed howitzer and not only offering a capable armour piercing capacity at short ranges, it offered a superior bunker bashing capability thanks to the High Explosive rounds it fired. The 122m A19 had been around since the 1930’s and had an established manufacturing infrastructure behind it, which also supported the decision to adopt it as the main gun.
AKA the D25-T, it used a two part ammunition. The HE round or Armour piercing round was loaded in to the breach and then the combustible charge was loaded after, at which point the breach was closed and the gun fired. Two 9.62mm and one 12.7mm MG’s were used as secondary armaments.
Armour
The KV series had an all-round respectful level of protection, but the IS series had a better layout enabling it to offer a greater level of frontal protection against the German Tiger and Panther tanks main guns.
Built of an all steel construction its frontal armour was equivalent to 160mm thickness and the turret layout meant it had a lower profile than those of German tanks making it a harder target to hit.
Mobility
Engine 600hp 12-cyl. diesel model V-2
Power/weight 13 hp/tonne
Suspension torsion bar
Fuel capacity 820 litres (180 imp gal; 220 US gal)
Operational range 240 km (150 mi)
Speed 37 km/h (23 mph)
Production & Development
Designer Zh. Kotin, N. Dukhov
Designed 1944
Manufacturer Kirov Factory, UZTM
Produced 1945 – 47
Number built 2311
The Russian IS-3 Heavy Tank Service History
The IS-3 was used in the 1956 Soviet invasion of Hungary and the Prague Spring in 1968.
During the early 1950s all IS-3s were modernised as IS-3M models. The Egyptian Army acquired about 100 IS-3M tanks in all from the Soviet Union. During the Six Day War, a single regiment of IS-3M tanks was stationed with the 7th Infantry Division at Rafah and the 125th Tank Brigade of the 6th Mechanized Division at Kuntilla was also equipped with about 60 IS-3M tanks.
Israeli infantry and paratrooper units had considerable difficulty with the IS-3M when it was encountered due to its thick armour, which shrugged off hits from normal infantry anti-tank weapons such as the bazooka. Even the 90 mm AP shell fired by the main gun of the Israeli Defense Force (IDF) M48 Patton tanks could not penetrate the frontal armour of the IS-3s at normal battle ranges.