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The NR-30 cannon is an automatic weapon with
a continuous, double-sided belt feed, the opera-
tion of which is based on the principle of using
recoil energy with a short barrel recoil. During
barrel recoil, the rotary bolt is unlocked and ac-
celerated backward by a lever accelerator. A gas
gate is used to brake the barrel recoil and bring
it back to its forward position - it uses gunpowder
gases taken from within the gun barrel. These
gases are fed into the gas cylinder through chan-
nels and fill the working space in front, sealed by
the piston and at the rear by inserts with sealing
rings. During barrel recoil, the barrel collar first
hits the piston, causing it to move with the collar
and the barrel as the recoil continues. The gas
channels are closed off by engaging the insert
sealing rings and the gases in the gas cylinder
are compressed. Their pressure exerts a force on
the piston surface that slows the barrel‘s back-
ward momentum and, after stopping, returns it
to the forward position. Just before reaching this
forward position, the gunpowder gases from the
cylinder are blown out of the system.
The simple rifled barrel is supplemented with
a muzzle brake in some variants of the weap-
on, which simultaneously functions as a flame
suppressor and directs the escaping exhaust
gases outside the aircraft. The gun is cocked
pneumatically (by compressed air), and fired
electronically, by releasing the bolt from the
rear position. The electric trigger circuit includes
a round counter and a signal indicating the need
for pneumatic cocking. A silencer is inserted be-
tween the weapon and its mount in the aircraft.
The NR-30 aircraft cannon was designed by Soviet designers A. E. Nudelman and A. A. Richter in the mid-1950s. The name
of the weapon was derived from the initials of their surnames (Nudelman, Richter) and the number ‘30’ refers to the weap-
on’s caliber. This period was characterized by a great boom in the design and production of new types of jet aircraft in the
Soviet Union and, by extension, their internal gun armament. This specific cannon was gradually installed in the Mikoy-
an-Gurevich MiG-19S fighter (three in the nose of the aircraft, all equipped with a muzzle brake at the end of the barrel),
the supersonic MiG-21F (on the right side of the fuselage, below the cockpit), the Sukhoi Su-7BM, BKL fighter-bombers
(one in each wing root, just behind the cockpit, without muzzle brakes) and later the Su-17 M3, M4, UM-3 (the latter two-
seat version with only one cannon in the right wing) and its export variants Su-22M3, M4, UM-3K, with a like number of
cannons as the Su-7. Due to the political division of the world at that time and the existence of a military grouping of
countries in the socialist camp, called the Warsaw Pact, the above-mentioned types gradually entered the inventory of
the air force of the former ČSLA (Czechoslovak People‘s Army). The ammunition was initially produced in and imported
from the Soviet Union, but later it began to be produced in Czechoslovakia, initially under license, but later as an evolution
under its own development program. The weapon was designed to deal with aerial as well as ground targets effectively.
The NR-30
Aircraft
Mounted
Weapon
Tomáš Dedera
HISTORY
INFO Eduard
7
January 2025