The "Condensator-2P" heavy self-propelled gun

After the end of the World War Two, additional works were accomplished to develop a new self-propelled gun on the base of IS-3. The new SPG was armed with the 152 mm gun-howitzer ML-20SM. This SPG distinguished from its predecessors (the ISU-122 and the ISU-152) by increased armor protection and improved angles of the frontal armor. However, due to several serious drawbacks this SPG did not put in a mass production, while a mass production of the ISU-152 has continued up to 1955, and 2450 vehicles were built in a post-war period (plus a 4075 were produced in a time of war). The manufacturing of ISU-122 was cancelled just after the end of war, but in 1947 its production was re-started and has continues up to 1952 and about 3130 were produced. After the end of war these both assault gun were modernised twice: in 1956 and 1959.

At the end of 1950th a two new self-propelled guns have been developed: a SPG of a special purpose "Condensator" (armed with 406 mm SM-54 gun) and "Oka" (armed with 420 mm mortar of Shavyrin's design). Both vehicles were based on ISU (IS) chassis. That was a Russian answer on a new American 280 mm "nuclear gun".

The self-propelled gun-mortar Oka. The self-propelled gun-mortar Oka.

At the beginning of 1960th, after the introducing of a R-11 "Skad" and a "Luna" (FROG-3) missiles, the chassis of ISU was choosed for a new 8K11 (SS-1b "Skad") missile launchers. Later, they have been modernised for launching a R-17 "Zemlya" missiles, and those launchers were renamed 8K11/8K14 (SS-1c "Skad B"). These modernised missile launchers served in Soviet Army since 1961, but sooner they were replaced with 9P117 (wheeled variant).

From 1959 some existed ISU were modernised to heavy prime movers BTT-1. In 1960 they were modernised and renamed BTT-1T. Though the IS tank were not exported in large amount, their variants used widely outside the USSR.

Most of all those vehicles (which were based on IS chassis) served in Poland: 10 ISU-152s and 22 ISU-122s. The Poles formed the 25th Self-Propelled Artillery Regiment that completely consisted of ISU-122 assault guns.

As element of the 13th Polish Tank Corps this regiment took part in battles at Nysa river in March of 1945. The Poles wanted to form one more regiment (a 13th Self-Propelled Artillery Regiment) but they didn't because of lack of proper number of ISU-152.

As a result, the 13th Regiment had a mix structure: two batteries of ISU-152 (5 tanks per battery) and two batteries of SU-85 (5 tanks per battery as well). That unit took part in Berlin Operation. ISU remained in Polish service after the end of war, some of them were modified as repair-evacuation vehicles (at the end 1960th).

Egypt was a single country that bought a large amount of ISU-152. By the beginning of 1960th it had at least one regiment equipped with ISU-152. During a wars in 1967 and in 1973, Egypt used these assault guns. Later, ISU-152 have been used as a pillboxes along the Suez Canal.

2K1 rocket launchers on military parade at the Red Square.

The 8K11 and 8K11/8K14 rocket launchers were used widely by Poland, Czechoslovakia, Eastern Germany, Rumania, Hungary and Bulgaria. These countries received that weapons in 1960-1961 as a part of a weapon modernisation program (for Warsaw Block only).

Later, Poland and Eastern Germany replaced their tracked 8K11 and 8K11/8K14 with more reliable wheeled variant 9P117. By the way, the 9P117 was based on the MAZ-543 heavy wheeled truck.