Berezin UB (Березин УБ - Универсальный Березина, Universalni Berezina, Berezin Universal) was a 12.7 mm caliber Soviet aircraft machine gun widely used during World War II.

Contents 1 Development 2 Description 3 Specifications (UBS) 4 References 5 Related content

[edit] Development

In 1937, M.E. Berezin began designing a new large-caliber aircraft machine gun chambered to the 12.7 mm round used by infantry machine guns. The new design passed factory trials in 1938 and was accepted into service in 1939 under the designation BS (Березин Синхронный, Berezin Sinkhronniy, Berezin Synchronized). The rate of fire was about twice that of the comparable M2 Browning machine gun, making it well suited for use as defensive armament in aircrafts. While a successful design, BS was not without its faults, the biggest being its cable-operated charging which required considerable physical strength. Continued development resulted in the improved UB which came in three versions: UBK (Kрыльевой, Krylyevoi, for the wings), UBS (Синхронный, Sinkhronniy, Synchronized), and UBT (Турельный, Turelniy, for the turret), with UBS and UBK charged by compressed air. UB was accepted into service on April 22, 1941, just two months before the start of the Great Patriotic War.

[edit] Description

The Berezin UB is a gas-operated air-cooled machine gun chambered to the Soviet 12.7 x 108 mm infantry machine gun round. Ammunition is supplied via a disintegrating link belt with a unique system in which each new round helps to extract the spent cartridge. Another unusual feature is that the belt is advanced during the return of the moving portion of the gun and not during the recoil. Turret installations were charged manually, while wing and synchronized versions utilized pneumatic charging.

The UB in all variants was used by the vast majority of Soviet military aircraft of World War II.

[edit] Specifications (UBS)

• Ammunition: 12.7 x 108 mm (0.5 x 4.3 in)
• Empty weight: 21.5 kg (47.3 lb)
• Muzzle velocity: 814-850 m/s (2,670-2,790 ft/s)
• Rate of fire: 800-1050 rounds/min
• Mass of one-second burst: 0.8 kg (1.8 lb)

[edit] References

• Широкоград А.Б. (2001) История авиационного вооружения Харвест (Shirokograd A.B. (2001) Istorya aviatsionnogo vooruzhenia Harvest. ISBN 985-433-695-6) (History of aircraft armament)

[edit] Related content

Related developments:

• Berezin B-20 autocannon

Similar weapons:

• M2 Browning machine gun

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