The first Soviet 30-mm mount was the AK-230 60-calibre system which entered service in 1960 to replace the elderly 25-mm 60-calibre twin antiaircraft gun on new-build major and minor warship classes. The small enclosed turret is usually known by the nickname Dalek because of its physical appearance. The two 30-mm cannon fitted are fully automatic in operation, and the barrels are water-cooled. The theoretical maximum rate of fire for the guns is 1,050 rounds per minute, but the maximum realistic rate to prevent damage is actually in the region of 200240 rounds per minute. The guns are usually used in conjunction with a 'Drum Tilt' fire-control radar or a remote optical director. On the smaller ships fitted with the AK-230 an anti-surface role is also assigned to the type, the maximum effective range being 2500 m (2,739 yards). A shell weighing 0.54 kg ( 1.2 Ib) is used. The system has been widely exported to Soviet-supplied states as the gun forms the main armament of the 'Osa' class missile craft.

To counter the threat of missile attack the Soviets developed the 30mm weapon further to produce a 'Gatling' gun version with six 30-mm barrels inside a larger barrel-like cylinder in a similar shaped mount known by the designation AK-630. This is designed to fire at a fast rate as large a number of the 0.54-kg ( 1.2-Ib) shells as possible, with high-density metal penetrators to destroy cruise missile sized targets at relatively close range. Usually

mounted in pairs with a 'Bass Tilt' fire control radar, the mount is in service on the 'Kiev', 'Kara', 'Udaloy', 'Sovremenny', 'Slava' and 'Kresta II' classes, and has been retrofitted to several older ships. On smaller warships it is usually found as a single mount together with a larger-calibre gun and a fire-control radar. Each mount also has a remote fire-control optical director.

Specification AK-230

Calibre: 30 mm Number of barrels: two Elevation: 0° to +85°

Muzzle velocity: 1000 m (3, 281 ft) per second

Effective range: 2500 m (2, 735 yards) Rate of fire: l, 050 rounds per minute

Specification AK-630

Calibre: 30 mm Number of barrels: six Elevation: 0° to +85°

Muzzle velocity: 1000 m (3, 281 ft) per second

Effective range: 3000 m (3, 280 yards) Rate of fire: 3, 000 rounds per minute