YakB-12.7 machine gun

{{Infobox weapon

|name=Yak-B machine gun

| image= Letecké muzeum Kbely (15).jpg

| image_size = 300

|caption=Yakushev-Borzov YakB-12.7 machine gun in the Prague Aviation Museum)

|origin= Soviet Union

|type=Aircraft rotary heavy machine gun

|is_ranged=yes

|is_artillery=yes

|service=1973–present

|used_by=

|manufacturer= KBP Instrument Design Bureau

|designer = KBP

|design_date=

|production_date=

|variants=

|spec_label=

|weight= 45 kg (99 lbs), cartridge weight 0.130 kg,

bullet weight 0.048 kg

|length={{convert|1.345|m|ft|abbr=on|sigfig=1}}

|width={{convert|0.13|m|ftin|abbr=on}}

|height=

|caliber=12.7 mm

|cartridge=12.7×108mm

|barrels= 4

|action= Gas-operated

|rate= 4,000–5,000 rounds/min{{Citation needed|date=February 2015}}

|velocity= 810 m/s (2,657 ft/s)

}}

The Yakushev-Borzov YakB-12.7 mm{{cite web|url=http://weaponsystems.net/weaponsystem/II04%20-%20Yak-B.html |title=Yakushev-Borzov Yak-B |publisher=Weaponsystems.net |access-date=2018-04-22}} 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{{cite web|url=http://www.faqs.org/docs/air/avhind1.html#m3 |title=[1.0] Hind Variants / Soviet Service |publisher=Faqs.org |access-date=2018-04-22}} but it is still used on Mil Mi-24,{{Cite book | url=https://books.google.com/books?id=tlW1CwAAQBAJ&q=Mil+mi+40+Yak-B+12.7mm&pg=PA48 |title = Mil Mi-24 Hind Gunship|isbn = 9781846039546|last1 = Mladenov|first1 = Alexander|date = 2012-07-20}} Mil Mi-36, and Mil Mi-40 helicopters.