Post by Diarist on Jul 27, 2014 11:46:48 GMT 1
The Browning Automatic Rifle (BAR) is a family of United States automatic rifles (or machine rifles) and light machine guns used by the United States and numerous other countries. The primary variant of the BAR series is the M1918, chambered for the .30-06 Springfield rifle cartridge and designed by John Browning in 1917 for the U.S. Expeditionary Corps in Europe as a replacement for the French-made Chauchat and M1909 Benet-Mercie machine guns.
The BAR was designed to be carried by advancing infantrymen, slung over the shoulder or fired from the hip, a concept called "walking fire"—thought to be necessary for the individual soldier during trench warfare. However in practice, it was most often used as a light machine gun and fired from a bipod (introduced in later models).
Development
In 1917, prior to America's entry in the war, John Browning personally brought to Washington, D.C. two types of automatic weapons for the purposes of demonstration: a water-cooled machine gun (later adopted as the M1917 Browning machine gun) and a shoulder-fired automatic rifle known then as the Browning Machine Rifle or BMR, both chambered for the standard U.S. .30-06 Springfield cartridge. Browning had arranged for a public demonstration of both weapons at a location in southern Washington, D.C. known as Congress Heights. There, on 27 February 1917, in front of a crowd of 300 people (including high-ranking military officials, Congressmen, Senators, foreign dignitaries and the press), Browning staged a live fire demonstration which so impressed the gathered crowd, that he was immediately awarded a contract for the weapon and it was hastily adopted into service (the water-cooled machine gun underwent further testing).
Design details and accessories
The M1918 is a selective fire, air-cooled automatic rifle using a gas-operated long-stroke piston rod actuated by propellant gases bled through a vent in the barrel. The bolt is locked by a rising bolt lock. The gun fires from an open bolt. The spring-powered cartridge casing extractor is contained in the bolt and a fixed ejector is installed in the trigger group. The BAR is striker fired (the bolt carrier serves as the striker) and uses a trigger mechanism with a fire selector lever that enables operating in either semi-automatic or fully automatic firing modes. The selector lever is located on the left side of the receiver and is simultaneously the manual safety (selector lever in the "S" position – weapon is "safe", "F" – "Fire", "A" – "Automatic" fire). The "safe" setting blocks the trigger.
The weapon's barrel is screwed into the receiver and is not quickly detachable. The M1918 feeds using double-column 20-round box magazines, although 40-round magazines were also used in an anti-aircraft role; these were withdrawn from use in 1927. The M1918 has a cylindrical flash suppressor fitted to the muzzle end. The original BAR was equipped with a fixed wooden buttstock and closed-type adjustable iron sights, consisting of a forward post and a rear leaf sight with 100 to 1,500 yard range graduations.
As a heavy automatic rifle designed for support fire, the M1918 was not fitted with a bayonet mount and no bayonet was ever issued. Only one experimental bayonet fitting was ever made for the BAR by Winchester. This was a standard, M1917 bayonet fitted at the Winchester factory with a special muzzle ring. The bayonet was attached to a standard M1918 BAR by means of a special experimental flash hider assembly.
Variants and subsequent models
During its lengthy service life, the BAR underwent continuous development, receiving many improvements and modifications. The first major attempt at improving the M1918 resulted in the M1922 light machine gun, adopted by the United States Cavalry in 1922. The weapon used a new heavy profile ribbed barrel, an adjustable spiked bipod (mounted to a swiveling collar on the barrel) with a rear, stock-mounted monopod, a side-mounted sling swivel and a new rear endplate, fixed to the stock retaining sleeve. The handguard was changed, and in 1926, the BAR's sights were redesigned to accommodate the heavy-bullet 172-grain M1 .30-06 ball ammunition then coming into service for machine gun use.
In 1931, the Colt Arms Co. introduced the Colt Monitor Automatic Machine Rifle (R 80), intended primarily for use by prison guards and law enforcement agencies. Intended for use as a shoulder-fired automatic rifle, the Colt Monitor omitted the standard bipod, instead featuring a separate pistol grip and buttstock attached to a lightweight receiver, along with a shortened 458 mm (18.0 in) barrel fitted with a 4-inch (100 mm) Cutts compensator. Weighing 16 lb. 3 oz. empty, the Colt Monitor had a rate of fire of approximately 500 rpm. Around 125 Colt Monitor automatic machine rifles were produced; of these ninety were purchased by the FBI. Eleven rifles went to the U.S. Treasury Department in 1934, while the rest went to various state prisons, banks, security companies, and accredited police departments. Although the Colt Monitor was available for export sale, no examples appear to have been exported to other countries.
In 1932, a greatly shortened version of the M1918 BAR designed for 'bush warfare' was developed by USMC Major H.L. Smith, and was the subject of an evaluative report by Capt. Merritt A. Edson, Ordnance officer at the Quartermaster's Depot in Philadelphia, Pennsylvania. The barrel was shortened nine inches (229 mm) at the muzzle, and the gas port and gas cylinder tube were relocated. The modified BAR weighed 13 lb. 12 oz. and was only 34.5 inches (880 mm) long overall. Though it proved superior to the M1918 in accuracy when fired in automatic mode using the prone position, and equal in accuracy to the standard M1918 at ranges of 500-600 yards when fired from a rest, it was less accurate when fired from the shoulder, and had a loud report combined with a fierce muzzle blast. Attaching a Cutts compensator materially reduced the muzzle blast, but this was more than offset by the increase in smoke and dust at the muzzle when fired, obscuring the operator's vision. Nor did it improve control of the weapon when fired in bursts of automatic fire. Though the report recommended building six of these short-barrelled 'jungle' BARs for further evaluation, no further work was done on the project.
Source: Wikipedia - en.wikipedia.org/wiki/M1918_Browning_Automatic_Rifle
The BAR was designed to be carried by advancing infantrymen, slung over the shoulder or fired from the hip, a concept called "walking fire"—thought to be necessary for the individual soldier during trench warfare. However in practice, it was most often used as a light machine gun and fired from a bipod (introduced in later models).
Development
In 1917, prior to America's entry in the war, John Browning personally brought to Washington, D.C. two types of automatic weapons for the purposes of demonstration: a water-cooled machine gun (later adopted as the M1917 Browning machine gun) and a shoulder-fired automatic rifle known then as the Browning Machine Rifle or BMR, both chambered for the standard U.S. .30-06 Springfield cartridge. Browning had arranged for a public demonstration of both weapons at a location in southern Washington, D.C. known as Congress Heights. There, on 27 February 1917, in front of a crowd of 300 people (including high-ranking military officials, Congressmen, Senators, foreign dignitaries and the press), Browning staged a live fire demonstration which so impressed the gathered crowd, that he was immediately awarded a contract for the weapon and it was hastily adopted into service (the water-cooled machine gun underwent further testing).
Design details and accessories
The M1918 is a selective fire, air-cooled automatic rifle using a gas-operated long-stroke piston rod actuated by propellant gases bled through a vent in the barrel. The bolt is locked by a rising bolt lock. The gun fires from an open bolt. The spring-powered cartridge casing extractor is contained in the bolt and a fixed ejector is installed in the trigger group. The BAR is striker fired (the bolt carrier serves as the striker) and uses a trigger mechanism with a fire selector lever that enables operating in either semi-automatic or fully automatic firing modes. The selector lever is located on the left side of the receiver and is simultaneously the manual safety (selector lever in the "S" position – weapon is "safe", "F" – "Fire", "A" – "Automatic" fire). The "safe" setting blocks the trigger.
The weapon's barrel is screwed into the receiver and is not quickly detachable. The M1918 feeds using double-column 20-round box magazines, although 40-round magazines were also used in an anti-aircraft role; these were withdrawn from use in 1927. The M1918 has a cylindrical flash suppressor fitted to the muzzle end. The original BAR was equipped with a fixed wooden buttstock and closed-type adjustable iron sights, consisting of a forward post and a rear leaf sight with 100 to 1,500 yard range graduations.
As a heavy automatic rifle designed for support fire, the M1918 was not fitted with a bayonet mount and no bayonet was ever issued. Only one experimental bayonet fitting was ever made for the BAR by Winchester. This was a standard, M1917 bayonet fitted at the Winchester factory with a special muzzle ring. The bayonet was attached to a standard M1918 BAR by means of a special experimental flash hider assembly.
Variants and subsequent models
During its lengthy service life, the BAR underwent continuous development, receiving many improvements and modifications. The first major attempt at improving the M1918 resulted in the M1922 light machine gun, adopted by the United States Cavalry in 1922. The weapon used a new heavy profile ribbed barrel, an adjustable spiked bipod (mounted to a swiveling collar on the barrel) with a rear, stock-mounted monopod, a side-mounted sling swivel and a new rear endplate, fixed to the stock retaining sleeve. The handguard was changed, and in 1926, the BAR's sights were redesigned to accommodate the heavy-bullet 172-grain M1 .30-06 ball ammunition then coming into service for machine gun use.
In 1931, the Colt Arms Co. introduced the Colt Monitor Automatic Machine Rifle (R 80), intended primarily for use by prison guards and law enforcement agencies. Intended for use as a shoulder-fired automatic rifle, the Colt Monitor omitted the standard bipod, instead featuring a separate pistol grip and buttstock attached to a lightweight receiver, along with a shortened 458 mm (18.0 in) barrel fitted with a 4-inch (100 mm) Cutts compensator. Weighing 16 lb. 3 oz. empty, the Colt Monitor had a rate of fire of approximately 500 rpm. Around 125 Colt Monitor automatic machine rifles were produced; of these ninety were purchased by the FBI. Eleven rifles went to the U.S. Treasury Department in 1934, while the rest went to various state prisons, banks, security companies, and accredited police departments. Although the Colt Monitor was available for export sale, no examples appear to have been exported to other countries.
In 1932, a greatly shortened version of the M1918 BAR designed for 'bush warfare' was developed by USMC Major H.L. Smith, and was the subject of an evaluative report by Capt. Merritt A. Edson, Ordnance officer at the Quartermaster's Depot in Philadelphia, Pennsylvania. The barrel was shortened nine inches (229 mm) at the muzzle, and the gas port and gas cylinder tube were relocated. The modified BAR weighed 13 lb. 12 oz. and was only 34.5 inches (880 mm) long overall. Though it proved superior to the M1918 in accuracy when fired in automatic mode using the prone position, and equal in accuracy to the standard M1918 at ranges of 500-600 yards when fired from a rest, it was less accurate when fired from the shoulder, and had a loud report combined with a fierce muzzle blast. Attaching a Cutts compensator materially reduced the muzzle blast, but this was more than offset by the increase in smoke and dust at the muzzle when fired, obscuring the operator's vision. Nor did it improve control of the weapon when fired in bursts of automatic fire. Though the report recommended building six of these short-barrelled 'jungle' BARs for further evaluation, no further work was done on the project.
Source: Wikipedia - en.wikipedia.org/wiki/M1918_Browning_Automatic_Rifle