ZSU-23-4 Shilka

ZSU-23-4 "Shilka"
A ZSU-23-4 on display
Type	Self-propelled anti-aircraft gun
Place of origin	Soviet Union
Service history
In service	1962–present
Used by	See Operators
Wars	See Combat history
Production history
Designed	1957–1962
Manufacturer	Mytishchi Engineering Works (MMZ)
Produced	1964–1982
Number built	About 6,500
Specifications
Weight	19 tonnes
Length	6.535 m
Width	3.125 m
Height	2.576 m (3.572 m with elevated radar)
Crew	4 (commander, driver, gunner, radar operator)
Armor	Welded steel, 9.2 mm turret, up to 15 mm hull
Main armament	4 × 23 mm 2A7 autocannons (AZP-23 "Amur" quad automatic anti-aircraft gun), ammunition 2,000 rounds
Engine	V-6R, 6-cylinder 4-stroke airless-injection water-cooled 20 litre diesel 280 hp (209 kW) at 2,000 rpm
Power/weight	14.7 hp/tonne (11.0 kW/tonne)
Suspension	Individual torsion bar with hydraulic shock absorbers of 1st, 5th left and 6th right road wheels
Ground clearance	375 mm
Fuel capacity	515 l
Operational range	450 km (road), 300 km (off-road)
Speed	50 km/h (road), 30 km/h (off-road)

The ZSU-23-4 "Shilka" is a lightly armored Soviet self-propelled, radar guided anti-aircraft weapon system (SPAAG).

The acronym "ZSU" stands for Zenitnaya Samokhodnaya Ustanovka (Russian: Зенитная Самоходная Установка), meaning "anti-aircraft self-propelled mount"; the "23" signifies the bore diameter in millimeters; the "4" signifies the number of gun barrels. It is named after the Shilka River in Russia. Afghan soldiers nicknamed it the "sewing machine" due to the sound of firing guns. It is also referred to by its nickname of "Zeus".

The previous Soviet self-propelled anti-aircraft gun (SPAAG), the ZSU-57-2, was armed with two 57 mm ; it was aimed optically using a basic tracking and lead calculating system. The ZSU-57-2 was not particularly successful despite its very powerful autocannons; it could only carry a relatively small amount of ammunition, was inaccurate as it lacked radar and could not fire while on the move.

The ZPU series armed with 14.5 mm heavy machine guns carried on a towed mount for stationary, point air defence had a much higher rate of fire. The 23 mm version of this weapon system was known as the ZU-23-2, a towed mount carrying two 23 mm cannons. However, these towed or improvised truck-mounted weapons had similar disadvantages.

The development of the ZSU-23-4 "Shilka" began in 1957 along with ZSU-37-2 "Yenisei" and the vehicle was brought into service in 1965, replacing all ZSU-57-2s in air defense units toward the beginning of the 1970s. The ZSU-23-4 was intended for AA defense of military facilities, troops, and mechanized columns on the march; originally, the more powerful guns of "Yenisei" were judged to be effective at covering the inner dead-zone of Soviet surface-to-air missile systems despite the increased weight of the vehicle, but commonality prevailed. Initially, tank regiments should have had the anti-aircraft artillery battalion of "Shilka" (consisting of two batteries, four ZSU-23-4s in each). At the end of the 1960s, one battery was equipped with ZSU-23-4s and the other with ZSU-57-2s. Motorized rifle and tank regiment standard anti-aircraft batteries consisted of two platoons later (one platoon was equipped with four ZSU-23-4s and another with four mobile surface-to-air missile systems 9K31 Strela-1 or 9K35 Strela-10). The ZSU-23-4 combined a proven radar system, the non-amphibious chassis based on GM-575 tracked vehicle, and four 23 mm autocannons. This delivered a highly effective combination of mobility with heavy firepower and considerable accuracy. The ZSU-23-4 outclassed all NATO anti-aircraft guns at the time, and it is still regarded as posing a major threat for low-flying fixed-wing aircraft and helicopters.