| Yak-B machine gun | |
| Origin: | Soviet Union |
| Type: | Aircraft rotary heavy machine gun |
| Is Ranged: | yes |
| Is Artillery: | yes |
| Service: | 1973–present |
| Manufacturer: | KBP Instrument Design Bureau |
| Designer: | KBP |
| Weight: | 45 kg (99 lbs), cartridge weight 0.130 kg,bullet weight 0.048 kg |
| Length: | 1.345abbr=onNaNabbr=on |
| Width: | 0.13m (00.43feet) |
| Caliber: | 12.7 mm |
| Cartridge: | 12.7×108mm |
| Barrels: | 4 |
| Action: | Gas-operated |
| Rate: | 4,000–5,000 rounds/min |
| Velocity: | 810 m/s (2,657 ft/s) |
The Yakushev-Borzov YakB-12.7 mm[1] is a remotely controlled 12.7×108mm caliber four-barrel rotary heavy machine gun 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).
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.