BSA .5

BSA .5
Production information
Country of origin	United Kingdom
Manufacturer(s)	Birmingham Small Arms
Year(s) designed	1924
Technical specifications
Weapon type	Heavy machine gun Observer's gun
Caliber	.5 BSA
Action	Recoil-operated
Weight	46 pounds (21 kilograms)
Feed system	37 rounds
Cyclic rate	400rpm
Muzzle velocity	2,600 feet per second (790 metres per second)
Other information
Other name(s)	BSA M1924

The BSA .5, sometimes referred to as the Model 1924, was a British heavy machine gun produced by Birmingham Small Arms.

History

BSA designed this .5-inch machine gun in 1924. It was intended as an observer's gun on aircraft or an anti-aircraft gun on shipdecks, and was marketed for sale in these roles. The Royal Air Force arranged trials for the weapon in 1928 but found little to recommend in it, as its fire rate and magazine capacity were considerably lower than desired. No sales of the gun were made and by 1930 it was abandoned.

Design

Despite bearing a heavy resemblance to the Lewis gun, the BSA .5 internally had little in common, and was instead recoil-operated. The barrel and bolt carrier recoiled back upon firing until the bolt carrier would hit a stop while the barrel would reciprocate back into its original position. The empty casing would then eject while the bolt carrier was held back and then the carrier would be allowed to return forward when a new round was chambered. When the magazine depleted, both the barrel and carrier would remain recoiled, and the chamber open, until a new magazine was fitted.

The fire rate was low at 400 rounds per minute and Lewis-like flat-pan magazines held only 37 rounds, making it difficult to sustain lengthy fields of fire with the BSA .5. It was offered in both air-cooled and water-cooled variants, although it is not known if any of the latter version were ever produced.

The BSA .5 machine gun was chambered in a proprietary .5-inch BSA cartridge, which was roughly equivalent to the American .50 Browning cartridge.