Bren light machine gun

Development

At the close of the First World War in 1918, the British Army was equipped with two main automatic weapons; the Vickers Medium Machine Gun (MMG) and the Lewis Light Machine Gun (LMG). 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; the barrel could not be changed in the field, which meant that sustained firing resulted in overheating until it stopped altogether. In 1922, the Small Arms Committee of the British Army ran competitive trials to find replacement for the Lewis, between the Madsen, the Browning Automatic Rifle (BAR), the Hotchkiss, the Beardmore-Farquhar 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 machinegun were tested as they became available, and in 1930, a further set of extensive trials commenced. This time the weapons tested included the SIG Neuhausen KE7, the Vickers-Berthier and the Czechoslovak ZB vz.27. The Vickers-Berthier was later adopted by the Indian Army because it could be manufactured at once, rather than wait for the British Bren production run to finish; it too saw extensive service in World War II.

Following these trials, the British Army adopted the Czechoslovak ZB vz.26 light machine gun manufactured in Brno in 1935, although a slightly modified model, the ZB vz. 27, rather than the ZB vz. 26 which had been submitted for the trials. The design was modified to British requirements under new designation ZGB 33, which was then licensed for British manufacture under the Bren name. The major changes were in the magazine and barrel and the lower pistol grip assembly which went from a swiveling grip frame pivoted on the front of the trigger guard to a s 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 British cartridge, a change from the various rimless Mauser-design cartridges such as the 8mm 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, which used the same .303 ammunition as the standard British bolt-action rifle, the Lee–Enfield, firing at a rate of 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 in the photo, 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.

Second World War

In the British and Commonwealth armies, the Bren was generally issued on a scale of one per rifle section, with three rifle sections in each platoon. A further three Bren guns were issued to the Admin platoon of each rifle company. An infantry battalion also had a "carrier" platoon, equipped with Universal Carriers, most of which carried Bren guns. Parachute battalions from 1944 had an extra Bren in the AT 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, and spotted targets for Number 1.

Generally, the Bren was fired from the prone position using the attached bipod. 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. Every soldier would be trained to fire the Bren in case of an emergency, though these soldiers did not receive a Bren proficiency badge.

The Bren had an effective range of around 600 yards (550 m) when fired from a prone position with a bipod. Initial versions of the weapon were sometimes considered too accurate because the cone or pattern of fire was extremely concentrated. Soldiers often expressed a preference for worn-out barrels in order to spread the cone of fire and increase suppressive effects. Later versions of the Bren addressed this issue by providing a wider cone of fire.

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.

The 30-round magazine was in practice usually filled with 27 or 28 rounds to prevent jams and avoid wearing out the magazine spring. Care needed to be taken when loading the magazine to ensure that each round went ahead of the previous round, so that the .303 cartridge rims did not overlap the wrong way, which would cause a jam. The spent cartridge cases were ejected downwards, which was an improvement on the Lewis gun which ejected sideways, since the glint of them flying through the air could compromise a concealed firing position.

In general, the Bren was considered a reliable and effective light machine gun, though in North Africa it was reported to jam regularly unless kept very clean and free of sand or dirt. It was popular with British troops, who respected the Bren for its reliability and combat effectiveness. The quality of the materials used would generally ensure minimal jamming. When the gun did jam through fouling caused by prolonged firing, the operator could adjust the four-position gas regulator to feed more gas to the piston increasing the power to operate the mechanism. The barrel needed to be unlocked and slid forward slightly to allow the regulator to be turned. It was even said that all problems with the Bren could simply be cleared by hitting the gun, turning the regulator, or doing both. It was by general consent the finest light machine gun in the world of its period, and the most useful weapon provided to the (French) "maquis" .... accurate up to 1,000 meters, and (it) could withstand immense maltreatment and unskilled use. "Resistants" were constantly pleading for maximum drops of Brens.

A complicated tripod mount was available to allow the Bren to be used as an indirect-fire weapon, but this was rarely used in the field. The Bren was also used on many vehicles, including on Universal Carriers, to which it gave the alternative name "Bren Gun Carrier", and on tanks and armoured cars. However, it 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 right 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. The tripod could be adjusted to allow high angle fire. There were also several designs of less portable mountings, including the Gallows and Motley mounts. A 100-round pan magazine was available for the Bren for use in the anti-aircraft role.

The Bren's direct ancestor, the Czechoslovak ZB vz. 26, was also used in World War 2 by German and Romanian forces, including units of the Waffen SS. Many 7.92 mm ZB light machine guns were shipped to China, where they were employed first against the Japanese in World War II, and later against UN forces in Korea, including British and Commonwealth units. Some ex-Chinese Czech ZB weapons were also in use in the early stages of the Vietnam War.

Production of a 7.92 mm round model for the Far East was carried out by Inglis of Canada.

The Bren was also delivered to the Soviet Union as part of the lend-lease program

Post-war

The British Army, and the armies of various countries of the Commonwealth, used the Bren in the Korean War, the Malayan Emergency, the Mau Mau Uprising and the Indonesia–Malaysia confrontation, where it was preferred to its replacement, the belt-fed GPMG, on account of its lighter weight. In the conflict in the Northern Ireland (1969-1998), the British Army squad typically carried the L4A4 version of the Bren as the squad automatic weapon in the 1970s. During the Falklands War in 1982, 40 Commando Royal Marines carried one LMG and one GPMG per section. Its final operational deployment with the British Army, on a limited scale, was to the First Gulf War in 1991.

When the British Army adopted the 7.62 mm NATO cartridge, the Bren was re-designed to 7.62 mm calibre, fitted with a new bolt, barrel and magazine. It was redesignated as the L4 Light Machine Gun (in various sub-versions) and remained in British Army service into the 1990s. A slotted flash hider similar to that of the contemporary L1 rifle and L7 General Purpose Machine Gun replaced the conical flash hider. The change from a rimmed to rimless cartridge and nearly straight magazine improved feeding considerably, and allowed use of 20-round magazines from the 7.62 mm L1A1 Self-Loading Rifle. The 30-round magazine from the L4 also fitted the L1A1 rifle, but the magazine spring was not always strong enough to provide enough upward pressure to feed rounds correctly, this being remedied by stretching the magazine springs.

Completion of the move to a 5.56 mm NATO cartridge led to Army removing the Bren/L4 from the list of approved weapons and then withdrawing it from service. The fact that Bren guns had remained in service for so many years with so many different countries in so many wars says much about the quality of the weapon's design.

The Mark III Bren remained in limited use with the Army Reserve of the Irish Defence Forces until 2006, when the 7.62 mm GPMG replaced it. The Bren was popular with the soldiers who fired it (known as Brenners) as it was light and durable, and had a reputation for accuracy. The most notable use of the Bren by Irish forces was in the Congo Crisis during the 1960s, when the Bren was the regular army's standard section automatic weapon.

Bren guns were in service with the Rhodesian Security Forces during the Rhodesian Bush War, including a substantial number re-chambered for 7.62 mm cartridges similar to those examples in the British Army. The Rhodesian Bren guns continued to see frequent action until the 1970s, when they were largely replaced by the FN MAG. A few were captured and re-issued by the Zimbabwe People's Revolutionary Army (ZIPRA). Some examples were still in service with reservists of the British South Africa Police in 1980, and were inherited by the Zimbabwe Republic Police upon the country's internationally recognised independence. Zimbabwean policemen continued to deploy Bren guns during operations against ZIPRA dissidents throughout the early 1980s.

The South African Defence Force deployed Bren guns during the South African Border War alongside the more contemporary FN MAG as late as 1978.

Mark 1

From September 1937. The original Bren based on the Czechoslovak gun.

Features:

Mark 2

Introduced 1941. A simpler version of the Mk 1. Produced by Inglis of Canada and the Monotype Group through a number of component manufacturing factories. Sometimes known as the "Garage hands" model.

Features:

The Bren Mk2 was much simplified in the body, which although still being milled from a solid billet of steel, required significantly fewer milling operations than the Mk1 which gave it a much cleaner appearance. The bipod was simplified in design as well as not having extending legs. Most Mk2 bipods resembled a simple 'A' frame and were more 'soldier proof'. The Mk2 also featured a slightly higher rate of fire than the Mk1. The woodwork on the Mk2 was simplified by being less ornate and ergonomic, which sped up the manufacturing process. The barrel was also simplified by means of a non-stepped removable flash hider and in some cases, a barrel fore-end that was matte instead of highly polished. The buffered buttplate of the Mk1 was omitted and replaced with a sheet metal buttplate.

Mark 3

A shorter and lighter Bren made by Enfield from 1944 for the war in the East and for Airborne Forces. This was a conversion of the Mk1 whose main distinguishing feature was a shorter barrel.

Mark 4

As with the Mk3 but this was a conversion of a Mk2.

L4

A conversion of the Bren to 7.62mm NATO from 1958. Indian Army variants may be new-build, not conversions. L4 Brens can easily be identified by their different magazine. The British-issue L4 magazine is of 30-round capacity and has a slight curve. The L4 magazine was interchangeable with the L1A1 SLR magazine, so the L4 Bren also can be seen fitted with straight 20-round magazines from the SLR or with the straight 30-round magazine from the Australian L2A1 or Canadian C2A1 heavy-barrel SLR. The flash suppressor was changed from the cone type of .303 variants to a slotted type similar in appearance to that used on the SLR and L7 GPMG. All L4s are chambered for 7.62×51mm NATO rimless ammunition.

Taden gun

The Taden gun was a development of the Bren to use with the .280 British intermediate round proposed to replace the .303 in British service. The Taden was belt-fed with spade grips and would have replaced both the Bren and the Vickers machine gun. Although reliable it was not accepted due to the US-driven standardization within NATO on the larger 7.62×51mm NATO round.

Semiautomatic Bren guns

Many nations' militaries have disposed of their Bren guns as surplus to their needs. Surplus Brens have been imported to the United States for sale to collectors, but due to US gun laws restricting the importation of automatic weapons such guns must be legally destroyed by cutting up the receivers. A number of US gunsmiths have manufactured new semiautomatic Brens by welding the pieces of destroyed receivers back together, with modifications to prevent the use of full automatic parts, and fitting new fire control components capable of only semiautomatic fire. The balance of the parts are surplus Bren parts. Such "semiautomatic machineguns" are legally considered rifles under US Federal law and the laws of most states.

World War II production

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