ISU-152 Object 704 or Kirovec-2 1945 with 152mm Cannon Soviet Self-Propelled Howitzer Trumpeter 05575
The ISU-152 (Russian: Самоходная установка на базе танка ИС с орудием калибра 152мм, ИСУ-152, romanized: Samokhodnaya Ustanovka na baze tanka IS s orudiyem kalibra 152mm, meaning "IS tank based self-propelled installation with 152mm caliber gun") is a Soviet self-propelled gun developed and used during World War II. It was unofficially nicknamed Zveroboy (Russian: Зверобой; "beast killer")[1] in response to several large German tanks and guns coming into service, including Tigers and Panthers. Since the ISU-152's gun was mounted in a casemate, aiming it was awkward, and had to be done by repositioning the entire vehicle using the tracks. Therefore, it was used as mobile artillery to support more mobile infantry and armor attacks. It continued service into the 1970s and was used in several campaigns and countries.
Object 704 (Объект 704) was the factory designation for a prototype self propelled gun developed in 1945. Also known as the Kirovets-2, it was developed on the chassis of the Kirovets-1, the initial prototype of the project that became the IS-3. The overall height of the vehicle was reduced to 2,240 millimetres (7.35 ft), which was compensated with an increased width of the superstructure. It was armed with the 152.4 mm ML-20SM model 1944 (МЛ-20СМ обр. 1944 г.) gun-howitzer, with a barrel length of over 4.5 metres (15 ft) (29.6 calibers) and no muzzle brake. It had a maximum range of 13,000 metres (42,651 ft). The self-propelled gun carried 20 rounds of two-piece (shell and charge) armour-piercing and high-explosive ammunition. The armour-piercing round, weighing 48.78 kilograms (107.5 lb), had a muzzle velocity of 655 metres per second (2,149 ft/s). The rate of fire was 1-2 round/min. Object 704 had four hatches at the superstructure roof and one emergency hatch at the bottom of the hull behind the driver's seat, which had an armoured cover. The self-propelled gun carried two external 90-litre (19.8 imp gal; 23.8 US gal) fuel tanks, not connected to the supply system. The secondary armament of the fighting vehicle consisted of two 12.7×108 mm DShK machine guns, one anti-aircraft and one co-axial. The protection was increased by placing thicker armour at more radical angles. In the area of the gun, where the mantlet combined with the hull front behind it and the housing of the recoil mechanism, the armour thickness was 320 millimetres (13 in). Object 704 was the best protected of all experimental or production Soviet self-propelled guns of the Second World War. However, the radical incline of the superstructure walls combined with the increased recoil of the gun, due to the lack of a muzzle brake, significantly complicated the work of the crew, and for this reason it was not adopted.
