The Gryazev-Shipunov GSh-23L is a twin-barreled 23mm cannon developed by the Soviet Union, primarily for military aircraft use. It entered service in 1965, replacing the earlier Nudelman-Rikhter NR-23 cannon.

The GSh-23L works on the Gast principle developed by German engineer Karl Gast of the Vorwerk company in 1916. It is a twin-barreled weapon in which the firing action of one barrel operates the mechanism of the other. It provides a much faster rate of fire for lower mechanical wear than a single-barrel weapon, although it cannot match the rate of fire of an electric Gatling gun like the M61 Vulcan. The Gast principle has been little used in the West, but was popular in the former Soviet Union on a variety of weapons.

This cannon was standard fit on late-model MiG-21 fighters, most variants of the MiG-23, the SOKO J-22 Orao and IAR 93, and the tail turrets of the Tupolev Tu-22M 'Backfire' bomber and some late-model Tu-95s. In that application, it had the unusual ability to fire infrared flares and chaff rounds, allowing it to function as both a weapon and a dispenser of anti-missile countermeasures.

Some MiG-21 models carried the GSh-23L in an underfuselage gondola designated the GP-9, carrying the cannon and 200 rounds of ammunition; this was replaced by a more streamlined semi-conformal installation. There are also several gun pods available for mounting on external hardpoints: UPK-23 for air-to-air use, with one or two fixed GSh-23 guns and 200-400 rounds of ammunition, and SPPU-22 pods with traversable barrels for strafing.

Specifications

• Type: dual-barrel automatic cannon
• Caliber: 30 mm (1.18 in)
• Operation: Gast principle
• Length: N/A
• Weight (complete): 50 kg (105 lb)
• Rate of fire: 3,000 - 3,400 rpm
• Muzzle velocity: 720 m/s (2,362 ft/s)
• Projectile weight: 180 gram (6.35 oz)