The Object 704 (another designation: ISU-152 model 1945) was a Soviet prototype self-propelled gun from the end of World War II. Its main armament was a single 152 mm ML-20SM mod.1944 howitzer, and its additional armament was provided by two 12.7 mm DSzK machine guns.
Object 704 was built in 1945 as a far-reaching modification of the ISU-152 self-propelled gun, produced on a fairly large scale. During its construction, many elements from the following vehicles were used: ISU-152, IS-2 and IS-3. Particular emphasis was placed on the crew's cover, which resulted in the use of armor up to 160 mm thick, moreover, inclined at large angles - especially on the front and sides. It is quite commonly accepted that it was the best armored Soviet self-propelled gun of the Second World War. In addition, the designers managed to lower the silhouette of the car, which made it difficult to detect. The gun also had a different howitzer than the standard ISU-152, although it had the same caliber. However, due to the end of hostilities, as well as the low working comfort of the crew, the vehicle did not enter mass production. Only one copy of Object 704 was built.
The ISU-152 is a Soviet self-propelled gun (also classified as a tank destroyer) from the Second World War. The first prototypes of this vehicle appeared in 1943, and the weapon entered mass production and the line in the same year. The weight of the vehicle in the basic version was 46 tons. The drive was provided by a single 520 HP W-2-IS engine. It was armed with a 152.4 mm ML-20S cannon-howitzer and one 12.7 mm DSzK machine gun. The self-propelled gun ISU-152 was developed at the Fabryka im. Kirov in Chelyabinsk. Initially, it was assumed that the new vehicle would be structurally based on the KW-1s tank, but it was quickly decided to use the new IS-2 heavy tank for this purpose. It is worth adding that the ISU-152 shared many structural elements and components with the ISU-122 self-propelled gun, which of course greatly facilitated the production and operation of both types of vehicles. As the ISU-152 showed high combat value in the course of combat operations in 1944-1945, the vehicle remained in the line or reserve of the Soviet Army for a good part of the Cold War. After 1945, two modernized versions of this vehicle were built. The first one was called ISU-152K and was developed in 1953. It had a new engine (the same as in the T-54 tank) and an increased supply of fuel and transported ammunition. In 1959, a version of the ISU-152M was created, which differed slightly from the ISU-152K. Among other things, she used another machine gun as an additional weapon.