The Bren gun (Brno-Enfield) was a series of light machine guns (LMG) made by the United Kingdom in the 1930s and used in various roles until 1992. While best known for its role as the British and British Empire forces' primary infantry LMG in World War II, it was also used in the Korean War and saw service throughout the latter half of the 20th century, including the 1982 Falklands War. Although fitted with a bipod, it could also be mounted on a tripod or be vehicle-mounted.
The Bren gun was a licensed version of the Czechoslovak ZGB 33 light machine gun which, in turn, was a modified version of the ZB vz. 26, which British Army officials had tested during a firearms service competition in the 1930s. The designer was Václav Holek, a gun inventor and design engineer. The later Bren gun featured a distinctive top-mounted curved box magazine, conical flash hider, and quick change barrel.
In the 1950s, many Bren guns were re-barrelled to accept the 7.62×51mm NATO cartridge and modified to feed from the magazine for the L1 (Commonwealth version of the FN FAL) rifle as the L4 light machine gun. It was replaced in the British Army as the section LMG by the L7 general-purpose machine gun (GPMG), a belt-fed weapon. This was supplemented in the 1980s by the L86 Light Support Weapon firing the 5.56×45mm NATO round, leaving the Bren gun in use only as a pintle mount on some vehicles. The Bren gun was manufactured by Indian Ordnance Factories as the "Gun Machine 7.62mm 1B" before it was discontinued in 2012.
Name The name Bren was derived from Brno, the city in Czechoslovakia, where the Zb vz. 26 was designed (in the Zbrojovka Brno Factory) and Enfield, site of the British Royal Small Arms Factory.
Development
At the close of World War I in 1918, the British Army was equipped with two main automatic weapons; the Vickers medium machine gun (MMG) and the Lewis light machine gun. The Vickers was heavy and required a supply of water to keep it in operation, which tended to relegate it to static defence and indirect fire support. The Lewis, although lighter, was still heavy and was prone to frequent stoppages: its barrel could not be changed in the field, which meant that sustained firing resulted in overheating until it stopped altogether.
In 1922, to find a replacement for the Lewis, the Small Arms Committee of the British Army ran competitive trials between the Madsen machine gun, the M1918 Browning Automatic Rifle (BAR), the Hotchkiss M1909 machine gun, the Beardmore–Farquhar rifle, and the Lewis itself. Although the BAR was recommended, the sheer number of Lewis guns available and the difficult financial conditions meant that nothing was done. Various new models of light machine gun were tested as they became available, and in 1930, a further set of extensive trials commenced, overseen by Frederick Hubert Vinden. This time the weapons tested included the SIG Neuhausen KE7, the Vickers–Berthier and the Czechoslovak ZB vz. 27. The last did not meet high requirements for durability and reliability, mainly because gunpowder residue from British cordite was obstructing the gas tube (ZB vz. 27 was also sent in 7.92 Mauser instead of .303 British, but ZB already held a patent, Czech patent No. 36583 for a staggered magazine for rimmed rounds). The Vickers–Berthier was later adopted by the Indian Army because it could be manufactured at once, rather than wait for the British Lewis production run to finish; it too saw extensive service in World War II.
A modified variant with a shortened gas tube was tested again in June 1932, and then newly developed ZB-30 in .303 yet again tested in November. Receiving more feedback and incorporating it into the design by January 1933, yet two other modifications were tested by British representatives in Brno in July. One of the variants was selected, designated ZGB 33 (for Zbrojovka, Great Britain, 1933), and 10 samples were sent to England in autumn 1933. After additional trials in early 1934, more samples were ordered during the summer of 1934, and on May 24, 1935, the licence for British manufacture was finally acquired, and the design was adopted under the Bren name.
The major changes were in the magazine and barrel and the lower pistol grip assembly which went from a swivelling grip frame pivoted on the front of the trigger guard to a sliding grip frame which included the forward tripod mount and sliding ejection port cover. The magazine was curved in order to feed the rimmed .303 inch SAA ("Small Arms Ammunition") cartridge, a change from the various rimless Mauser-design cartridges such as the 7.9-mm Mauser round previously used by Czech designs. These modifications were categorised in various numbered designations, ZB vz. 27, ZB vz. 30, ZB vz. 32, and finally the ZGB 33, which was licensed for manufacture under the Bren name.
The Bren was a gas-operated weapon using the same .303 ammunition as the standard British bolt-action rifle, the Lee–Enfield, firing at a rate between 480 and 540 rounds per minute (rpm), depending on the model. Propellant gases vented from a port towards the muzzle end of the barrel through a regulator (visible just in front of the bipod) with four quick-adjustment apertures of different sizes, intended to tailor the gas volume to different ambient temperatures (smallest flow at high temperature, e.g. summer desert, largest at low temperature, e.g. winter Arctic). The vented gas drove a piston which in turn actuated the breech block. Each gun came with a spare barrel that could be quickly changed when the barrel became hot during sustained fire, though later guns featured a chrome-lined barrel, which reduced the need for a spare. To change barrels, the release catch in front of the magazine was rotated to unlock the barrel. The carrying handle above the barrel was used to grip and remove the hot barrel without burning the hands.
The Bren was magazine-fed, which slowed its rate of fire and required more frequent reloading than British belt-fed machine guns such as the larger .303 Vickers machine gun. The slower rate of fire prevented more rapid overheating of the Bren's air-cooled barrel, and the Bren was much lighter than belt-fed machine guns, which typically had cooling jackets, often liquid filled. The magazines also prevented the ammunition from getting dirty, which was more of a problem with the Vickers with its 250-round canvas belts. The sights were offset to the left, to avoid the magazine on the top of the weapon. The position of the sights meant that the Bren could be fired only from the right shoulder.
Service World War II
Organization and issue In the British and Commonwealth armies, the Bren was generally issued on a scale of one per rifle section. An infantry battalion also had a "carrier" platoon, equipped with Universal Carriers, each of which carried a Bren gun. Parachute battalions from 1944 had an extra Bren in the Anti-tank platoon. The 66-man "Assault Troop" of British Commandos had a nominal establishment of four Bren guns. Realising the need for additional section-level firepower, the British Army endeavoured to issue the Bren in great numbers, with a stated goal of one Bren to every four private soldiers.
The Bren was operated by a two-man crew, sometimes commanded by a Lance Corporal as an infantry section's "gun group", the remainder of the section forming the "rifle group". The gunner or "Number 1" carried and fired the Bren, and a loader or "Number 2" carried extra magazines, a spare barrel and a tool kit. Number 2 helped reload the gun and replace the barrel when it overheated,Pamphlet No. 4 "Lesson 12 - Elementary Handling (No.1 Assisted by No.2)" and spotted targets for Number 1. For a light machine gun of the interwar and early World War II era, the Bren was about average in weight. On long marches in non-operational areas it was often partially disassembled and its parts were carried by two soldiers. The top-mounted magazine vibrated and moved during fire, making the weapon more visible in combat, and many Bren gunners used paint or improvised canvas covers to disguise the prominent magazine.
A tripod mount with 42 degrees of traverse was available to allow the Bren to be used on "fixed lines" of fire for defensive shooting at pre-determined areas in the dark or if obscured by fog or smoke.
The Bren was also used on many vehicles, the Universal Carrier also known as the "Bren Gun Carrier", and on tanks and armoured cars. The Carrier was intended to use its "armour, speed and cross country performance" to bring the gun team into position from where it would fire dismounted; firing from the vehicle only in an emergency.
The Bren could not be used as a co-axial weapon on tanks, as the magazine restricted its depression and was awkward to handle in confined spaces, and it was therefore used on a pintle mount only. (The belt fed Vickers or Besa, the latter being another Czechoslovak machine gun design adopted by the British, were instead used as co-axial weapons.)
An unfortunate problem occurred when the Bren was fired from the Dingo Scout Car; the hot cartridge cases tended to be ejected down the neck of the driver, whose position was next to the pintle. A canvas bag was designed to catch the cartridges and overcome the problem, but it seems to have been rarely issued. The Bren was also employed in the anti-aircraft role with the tripod reconfigured for high angle fire. There were also several designs of less-portable mountings, including the Gallows and Mottley mounts. A 100-round pan magazine was available for the Bren for use in the anti-aircraft role.
Firing positions and assault use The Bren was generally fired from the prone position using the attached bipod."It [the L4A4 Bren] is normally fired from the shoulder in the lying position, supported by the bipod, although it may be fired from other positions to engage targets at close range". Chapter 1, Section 1, para 102, Australian Army Manual of Land Warfare, Part 2, Infantry Training, Vol 4 Pam 6, Machine Gun 7.62mm L4A4, Australian Government 1979. On occasion, a Bren gunner would use his weapon on the move supported by a sling, much like an automatic rifle, and from standing or kneeling positions. Using the sling, Australian soldiers regularly fired the Bren from the hip, for instance in the marching fire tactic, a form of suppressive fire moving forward in assault. A Victoria Cross was awarded to Private Bruce Kingsbury for such use at Isurava, New Guinea, in 1942, during the Australians' fighting retreat from Kokoda.
Each British soldier's equipment normally included two magazines for his section's Bren gun. The large ammunition pouches on the 1937 pattern web equipment were designed around the Bren magazine. The Bren was regarded as the principal weapon of an infantry section, providing the majority of its firepower. As such, all ranks were expected to be "experts in its use". The Bren had an effective range of around when fired from a prone position with a bipod. It could deliver a beaten ground of by at on the bipod. A 'rapid' fire rate of 120 rounds per minute (four magazines a minute) was sustainable with a barrel change after ten magazines (or reduction in fire rate) to limit wear but doctrine was to fire in 4-5 round bursts. Soldiers were instructed to fire single-shot in imitation of rifle fire to conceal the presence of an automatic weapon.Pamphlet No. 4 "Lesson 4 - Firing"
Magazine loading and ejection