One of the most important and iconic weapons of World War II was the British Bren light machine gun. The Bren’s distinctive top-mounted curved magazine made it easy to recognize by friend and foe alike. Troops throughout the British Empire praised the Bren for its reliability.
A Bren gun position in Burma, 1945. All photos in this article are from the Imperial War Museum.
During World War I, machine guns were used as defensive weapons, and were outstanding in that role; combined with barbed wire, they made it extremely difficult for the opposing force to advance. Both sides used very similar machine guns as well as similar tactics, and a stalemate ensued. Machine guns were belt-fed, mounted on heavy tripods, and fitted with a water-filled jacket to keep the barrel cool; with sufficient water and ammunition, a machine gun could fire almost indefinitely. Because of their weight and bulk, they were not easily moved and therefore kept in emplaced positions.
The light machine gun appeared towards the end of the war in an effort to break the stalemate by giving more firepower to the advancing infantry. These new weapons were air-cooled, portable, and typically magazine-fed. Arguably the best light machine gun of the time was the Lewis gun; however, it was mechanically complex, required more advanced training than a rifle, and was somewhat unreliable. However, it was vastly superior to the French Chauchat, which had a dreadful reputation for jamming; the American Browning Automatic Rifle (or “B.A.R.”), while more reliable, came out too late in the war to see much service.
In the 1930’s, the British Army’s Small Arms Committee began the search for a new light machine gun to replace the Lewis gun. They tested a number of weapons, including the Danish Madsen and the French FM 24/29, which had replaced the despised Chauchat. The American B.A.R. performed well in the trials and was an early favorite. However, it had a significant flaw: it had a fixed barrel, while the others had a detachable barrel. After extensive firing, the gun needed to cool; continued firing would cause permanent damage. The other light machine guns could have a spare barrel fitted, and then continue firing as before. As the trials continued, a new favorite emerged: the Czech Zb 26, made by the Brno arms factory. The Czechs made updates to the design based on feedback during the trials; what started as the Zb 26 eventually became the Zb 30 and then the Zb 33. The Brno designers called the final iteration the ZGB, which was adopted by the British government.
Late in the trials, the ZGB was given an endurance test. The plan was to fire 150,000 rounds and see how many stoppages would ensue. After about 146,000 rounds, the test was cut short because the gun was still firing as flawlessly as when it started, and the testers felt firing the last allocated rounds would simply be a waste of time and ammunition.
The original Zb series fired 7.92mm ammunition, the same round developed for the Mauser rifle. Late in the trials, the ZGB design was converted to fire British .303 ammunition, and the plans were converted from metric to Imperial measurements. A licensing agreement was signed allowing for the weapon to be built in Great Britain at the Royal Small Arms Factory at Enfield. The gun was given a new name: “Bren”, taken from “Brno” and “Enfield”.
The gun was officially adopted in 1935 and the first Bren was completed in 1937. When the British Expeditionary Force (B.E.F.) was sent to France and Belgium in 1939, enough Brens were available to equip most units. However, the gun was still new, and evidence suggests that not all units had been effectively trained in its use. Additionally, when the B.E.F. was first sent to the continent, most of the men were still wearing their old service dress uniforms with the 1908 pattern webbing equipment, which gave no method of carrying Bren magazines. Fortunately, most troops were re-equipped with the 1937 pattern webbing and battledress before the German invasion of France and the Low Countries in May of 1940; the new equipment had been designed around the Bren, with pouches large enough for the magazines.
After the Dunkirk evacuation, the Army conducted an inventory and found there were only about 2,300 Brens available. While most soldiers returned from France with their rifles, many of the Brens had been abandoned or intentionally destroyed, along with heavier weapons, vehicles, and supply dumps. If the weapon had not been so new, and the men more thoroughly trained in its use, it may not have been left behind in such numbers.
Dug-in British troops near Tobruk, Libya, in 1941. They were lucky to have a Bren; at this point, many troops were using the less-reliable Lewis gun.
As the war in North Africa intensified, there were insufficient Brens for the need, and stocks of old Lewis guns were brought out of storage. Britain also ordered a number of B.A.R.’s from the United States; but by the time they arrived, Bren production had increased and most of the B.A.R.’s went to the Home Guard. By late 1942, most units in the desert had been supplied with Brens. Since the Bren was more reliable under desert conditions than most other machine guns, this gave the British an advantage.
Upon adoption, the Bren had been intended as a multiple-use weapon in order to replace both the Lewis light machine gun and the Vickers water-cooled gun. A tripod was produced so that the Bren could be used in the sustained-fire role. By adding an extra leg, the tripod could be reconfigured to use the Bren as an anti-aircraft (A.A.) weapon; if anything happened to the tripod extension, an S.M.L.E. rifle could be substituted. A special A.A. sight could be clipped on the barrel, and an A.A. drum magazine was developed that could hold 100 rounds.
England, 1941. Volunteers of the Home Guard train on the Bren in the anti-aircraft configuration. This Mark I still has the rear grip.
The Bren was also mounted on vehicles. A brass-catching device, essentially a heavy canvas bag with steel mount, could be inserted into the ejection port. Every vehicle with a Bren was supposed to be issued with the brass-catcher, but this did not always happen; crews of Dingo armored cars in particular were subject to having hot brass dumped on them.
Unfortunately, the Bren was not particularly successful as a multi-purpose gun. Its slow rate of fire and magazine feed were not terribly effective for either the sustained fire role or as an anti-aircraft weapon. The magazine feed was fine in open-topped vehicles, but very awkward in the cramped confines of a tank. Eventually, the belt-fed Besa machine gun was adopted for use on tanks, and the old water-cooled Vickers gun was brought back into use for sustained fire in fixed positions. The Bren was also replaced by dedicated anti-aircraft guns, including the 20mm Polsten and Oerlikon guns and the 40mm Bofors gun.
As an infantry weapon, however, the Bren was outstanding. One Bren gun was issued to every eight-man section; its simple design made it easy to use. While each section had a dedicated Bren gunner who was authorized to wear a specialist’s badge (either “LMG” or “BG”), all troops were trained on its use so they could take over in time of need. The magazine feed meant that the ammunition was easily distributed throughout the section. The Bren fired the same .303 round as the Lee-Enfield rifles; during lulls in the fighting, the riflemen would reload empty magazines from their bandoliers.
The Bren was extremely robust. Its reliability was one of the main reasons it had been adopted, and the troops were very fond of it for that reason. This reliability was helped by the sliding dust-covers over both the magazine well and the ejection port, designed to keep dirt and debris out of the mechanism. Additionally, the gas system was adjustable; as cordite residue built up in the gun, a larger aperture in the gas regulator could be selected which would allow more gas to cycle through and work the action.
The Bren was also very accurate; in fact it was almost too accurate, and experienced gunners preferred using worn barrels to give a wider cone of suppressing fire. The top-mounted magazine required that the sights be offset by about a half-inch; this was not enough to have an appreciable impact on accuracy, especially at longer ranges. The Bren used an aperture rear sight and post front sight. Mounted on the tripod, the Bren’s effective range was around 2000 yards; on just the integral bipod, it was effective to over 600 yards.
The standard magazine had been intended to hold 30 rounds; however, this tended to over-compress the spring and cause feeding issues, so standard practice was to load 28 rounds. The magazine’s distinctive curved shape was required to accommodate rimmed .303 ammunition. Care had to be taken when loading the magazines to avoid overlapping the rims; most stoppages were caused by poorly-filled magazines, not by any mechanical issues with the gun itself. During trials, it was noted that the top-mounted magazine was faster and easier to change than guns with bottom-mounted magazines, particularly the B.A.R. Additionally, the B.A.R.’s magazine only held 20 rounds, as a larger capacity would impede the use of low cover.
Perhaps the most important feature of the Bren was the ability to change its barrel quickly; no tools were needed for this process. The magazine had to be removed and the magazine well’s dust cover closed. Raising the barrel nut unlocked the barrel, which was then lifted away by the carry handle; the spare was then installed and the barrel nut pressed back down. The barrel was changed after every 10 magazines during automatic fire, and a well-trained crew could do it in eight seconds. The barrel’s muzzle spread out in a conical shape as a rudimentary flash hider; the cone allowed expanding gas to dissipate more quickly than a straight muzzle.
Normandy, 1944. A Bren gunner has removed the barrel for cleaning.
The theoretical rate of fire was around 500 rounds per minute, but of course with magazine changes, the actual rate of fire was much lower, around 120 rounds per minute. Bren gunners were trained to fire 4-5 round bursts in suppressing fire or in engaging an exposed enemy. In the defense, gunners were taught to fire single rounds at suspected targets, not only to conserve ammunition, but also to try to disguise the nature of the gun and avoid becoming the enemy’s primary target.
The Germans used belt-fed air-cooled machine guns, namely the MG-34 and its successor, the MG-42. These guns, particularly the MG-42, were noted for their high rate of fire. They were extremely effective psychological weapons; troops confronted by these guns were terrified by the sound and easily suppressed. But this rate of fire came at a cost. The Germans went through a staggering amount of ammunition, all of which had to be carried by the infantrymen. It generally took longer to reload a belt-fed gun than one that was magazine-fed. The German guns also overheated much faster, and it was not as easy to change out their barrels; a thick felt pad was used to protect the soldiers’ hands while handling the hot barrel. The Germans encountered times when the spare barrel needed to be changed before the original had sufficiently cooled.
The Bren could be operated by a single soldier, but was more effective when crewed by a gunner and an assistant (The Bren Number 1 and Bren Number 2). The Number 1 carried the gun, three magazines (one in the gun, two in webbing pouches), and the spare parts wallet. The Number 2 carried six magazines, two in his regular webbing equipment, and four in supplemental pouches. He also carried the spare barrel in its dedicated webbing holdall. Typically, both magazine changes and barrel changes were done by the Number 2.
All infantry tactics revolved around the Bren gun, as it was the section’s primary fire-producer. Defensively, the Bren was put at the section’s flank in order to engage the attacking enemy with defilade fire. While the rest of the section dug straight 2-man slit trenches, the Bren was placed at the apex of an angled trench, which gave better access for the Number 2 to change magazines and barrels.
In the attack, the section would break into two groups: the Bren group consisted of the assistant section leader, the Bren Number 1 and Number 2; the section leader and the riflemen were the assault group. The groups would then engage in fire-and-movement, one group providing covering fire while the other group advanced. The goal was to get the Bren into a good position to engage the enemy and either destroy them or suppress them so the assault group could take the position.
The Bren was also an integral part of anti-tank tactics. While the .303 round would not penetrate a tank’s armor, it could force the tank commander and any other crew to stay inside the turret, reducing their visibility and effectiveness. Bren gunners were also taught to fire at a tank’s viewing ports and prisms; if this was not possible, they were to engage any supporting infantry. All of these tactics made it easier for an anti-tank team to move up on the vehicle’s flank with a Boyes anti-tank rifle or a PIAT (projector, infantry, anti-tank).
The Bren had an attached bipod, which could be folded up when mounted on a vehicle or tripod, or to allow the gunner to get into deeper cover. It also had a sling; the gun could be carried with the sling over the shoulder taking most of the weight, and the left hand steadying the gun. This way, the gun could be fired from the hip while on the move. The carry handle could be rotated into the “assault position”, although it was more common to hold the gun under the folded-up bipod when firing from the hip.
The first Bren gun, the Mark I, had a wooden rear grip, very much like the carry handle, but mounted under the buttstock. Bren gunners were trained to grasp the pistol grip with the right hand and the rear grip with the left; no allowance was made for firing the gun left-handed. While there was little recoil because of the mass of the gun, it still needed to be stabilized during firing. However, it was soon found that the rear grip did not provide enough stability and troops were instead taught to grasp the wrist of the stock, that is, the narrowest part. This method provided the stability needed. The rear grip was then eliminated in future versions of the Bren, and even removed from existing guns.
The Mark I had a dovetail slot cut into the receiver, or body, to accept an optical sight, intended for use when firing from the tripod in fixed positions. However, very few of the optical sights were issued; in fact, many of the sights were mounted on rifles and issued to snipers. The Mark I* receiver eliminated the dovetail.
The Mark I had an elevating wheel for its backsight, adjustable bipod legs, and the charging handle could be folded flat against the receiver after the gun had been cocked. The Mark II had a simpler leaf-type backsight, non-adjusting bipod legs, and a simpler, non-folding charging handle; it also had a simpler carry handle. These modifications were intended to increase manufacturing production, and it was estimated that the Mk II was nearly 25% more efficient to build than the Mk I. Towards the end of the war, the Mark III and Mark IV were approved for production; these Brens had shorter barrels than the earlier designs, and were intended for use by the Airborne forces, or in the jungle. However, the Marks III and IV came out too late to see much wartime service.
Troops on the march in Burma, 1945. Note the Bren gunner with the weapon resting on his shoulder.
Originally, Bren gunners were trained to carry the gun by the carry handle. However, “light machine gun” was a comparative term; it was only light compared to water-cooled machine guns. The Bren Mark I weighed 23 pounds unloaded, well over double the Lee-Enfield rifle, and the Bren Mark II weighed slightly more. Each full magazine weighed just short of three pounds. When not in direct contact with the enemy, Bren gunners tended to march with the gun balanced on the shoulder, with a hand on the barrel to steady the gun.
The Bren was used throughout the British Empire. Not only was it made at R.S.A.F. Enfield in England, it was also made by the John Inglis Company in Canada and the Lithgow arms factory in Australia. The Indian Army began the war with the similar-appearing Vickers-Berthier; however, the gun was not sufficiently robust, and India adopted the Bren in 1942 and built them at the Ishapore factory.
Royal Marines occupy a barn during the Falklands campaign, 1982. The L4 L.M.G., in 7.62mm, faces the camera.
The Bren continued service after World War II; its reliability was again needed from the bitter cold of Korea to the jungles of Malaya. When Britain adopted the NATO-standard 7.62mm cartridge in the late 1950’s, the Bren gun was converted to the new round and redesignated as the L4 L.M.G. While new barrels and magazines were made, existing guns were rechambered to 7.62mm. The new magazines were straight, not curved, and the muzzle cone was replaced with a “birdcage”-style flash hider. If needed, the L4 was able to use the same magazine as the L1A1 self-loading rifle. The L4 served nearly to the end of the 20th Century; its last use was in the 1991 Gulf War.
The last use of the classic British L.M.G. This young soldier mans his L4 in the Persian Gulf in 1990, during the build-up to the liberation of Kuwait.