YakB-12.7 machine gun

The Yakushev-Borzov YakB-12.7 mm[1] is a remotely controlled 12.7×108mm caliber four-barrel rotary cannon developed by the Soviet Union in 1973 for the Mil Mi-24 attack gunship and low-capacity troop transporter, with 1470 rounds, which can also be mounted in GUV-8700 machine-gun pods with 750 rounds. It has a high rate of fire (4–5,000 rounds per minute) and is also one of the few self-powered guns of the Gatling type (i.e. it is gas-operated, rather than requiring an external motor to operate).

Yak-B machine gun
Yakushev-Borzov YakB-12.7 machine gun in the Prague Aviation Museum)
Type	Aircraft rotary cannon
Place of origin	Soviet Union
Service history
In service	1973–present
Production history
Designer	KBP
Manufacturer	KBP Instrument Design Bureau
Specifications
Mass	45 kg (99 lbs), cartridge weight 0.130 kg, bullet weight 0.048 kg
Length	1.345 m (4 ft)
Width	0.13 m (5.1 in)
Shell	12.7×108mm
Caliber	12.7 mm
Barrels	4
Action	Gas-operated
Rate of fire	4,000–5,000 rounds/min
Muzzle velocity	810 m/s (2,657 ft/s)

On the Mi-24 it is mounted in the VSPU-24 undernose turret, with an azimuth of 60° to either side, an elevation of 20°, and a depression of 60°. The gun is slaved to the KPS-53AV undernose sighting system with a reflector sight in the front cockpit.

It was replaced by the fixed, side-mounted GSh-30K or the swivel-mounted GSh-23L in the late mark of the Mi-24 helicopters, as it did not provide enough firepower against dug-in or lightly armored targets that did not necessitate a rocket attack[2] but it is still used on Mil Mi-24,[3] Mil Mi-36, and Mil Mi-40 helicopters.