The Soviet Sewing Machine

The ZSU-23-4 "Shilka" is a lightly armored Soviet self-propelled, radar guided anti-aircraft weapon system. It is named after the Shilka River in Russia. Soviet soldiers nicknamed it the "sewing machine" due to the sound of firing guns.

The previous Soviet self-propelled anti-aircraft gun, the ZSU-57-2, was armed with two 57 mm autocannons; it was aimed optically using a basic tracking and lead calculating system. Although very powerful the ZSU-57-2 proved ineffective, particularly against fast jets. 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 aircraft and helicopters.

ZSU-23-4 units saw active service in the Yom Kippur War and other Arab-Israeli conflicts, the Iran–Iraq War and the First Gulf War During the 1973 Yom Kippur War, Egyptian and Syrian Shilkas proved very effective against the Israeli Air Force. Israeli pilots attempting to fly low in order to avoid SA-6 missiles were often shot down by ZSU-23-4s.