Nudelman-Rikhter NR-30

The Nudelman-Rikhter NR-30 was a Soviet autocannon widely used in military aircraft of the Soviet Union and Warsaw Pact. It was designed by A.E. Nudelman and A.A. Rikhter, entering service in 1954.

Description
The NR-30 was a single-barrel, short recoil operated cannon, essentially an enlarged version of the 23 mm NR-23 weapon introduced in 1949. It fired a massive projectile (more than twice the weight of the NR-23's 23 mm shell), requiring a muzzle brake with an integrated flame damper to prevent airframe damage from its firing. Before this gun, the Soviet standard fighter armament was two 23 mm and one 37 mm gun, that were ballistically quite different. The 23 mm was quite powerful, but with a relatively low initial velocity, while the 37 mm was lacking in rate of fire and ammunition reserve.

A MiG-15 typically had 80 cartridges for each 23 mm gun and 40 for the single 37 mm NR-37. The 30 mm gun was needed to make a weapon capable of combining the destructive power and the ballistic qualities of the 37 mm and the rate of fire typical of the 23 mm NR-23.

It had a velocity of around 800 m/s, a projectile weighing 400 grams (twice that of the 23 mm and half that of 37 mm guns), a rate of fire of 900 cycles per minute, even greater than NR-23, and a typical load of 70 shells for each gun. Generally it was fitted into the wings rather than in the nose. There were several types of ammunition, no less than 20 models. The most used were AP and HEI, the latter of 40–48 g HE internal charge (several times larger than 20 mm ammunition).

It was clear that this gun was meant to fire heavy projectiles, as DEFA guns (firing the far less powerful 30x113 ammunition) had projectiles weighing around 270 g, with similar velocity, but a better rate of fire (1200-1300 rounds per minute), more versed in air-to air engagements. DEFAs had typically 120-140 cartridges each. The NR-30 was also remarkably light, with more firepower (comparing rate of fire and projectile's weight) despite being one-third lighter. Only the GSh-301 is lighter among all the 30 mm guns. One unusual ammunition was the Chaff dispenser PRL, with 48,000 chaff particles internally, however it is unknown how it was used practically.



The NR-30 was used mainly in the MiG-19 (before this model, MiGs had 23 and 37 mm mixed armament), early MiG-21 models, the Sukhoi Su-7, and the Sukhoi Su-17. It was also used on the Shenyang J-6, the Chinese copy of the MiG-19, with a third gun in the nose. The Chinese manufactured their own version, the Type-30, which has slightly different characteristics, but is basically similar in operation.

Although its rate of fire makes it more suited for air-to-ground use, it is, by all accounts, a formidable weapon combining reasonable accuracy and devastating hitting power. It also appears a version of the gun was modified for use in space, with successful testing on a military Almaz station.

Ammunition specifications

 * Caliber: 30x155mm (belted) with a brass case
 * Projectile weight: 410 grams (14½ oz), 840 g (1 lb 13½ oz) complete
 * Launch charge: 95 g to 99 g of 6/7fl VBP smokeless powder
 * Types of ammunition: HEI, AP, TP, Chaff dispensers