For more U.S. machine gun history, go here.

Dr. Joseph Gatling laid the groundwork for what we now know as a machine gun, but the crank operated, multi-barreled guns were more of an artillery piece and a battlefield curiosity, but with the trench warfare of World War I served as a kind of crucible for the advancement of the technology.There were a number of missteps in machine gun development during the first Great War, as engineers saw the flaws in their designs readily exposed in the harsh, dirty, and demanding trenches. Designers went back to the drawing board and refined their guns bit by bit, inching them closer to the arms found on the modern battlefield.The Lewis Gun (1914)

A schematic of the Lewis Gun.
A schematic of the Lewis Gun. Wikimedia Commons

Despite being invented by U.S. Army Colonel Isaac Newton Lewis in 1911, the Lewis gun was not initially adopted by U.S. military forces. The reasons behind this rejection aren’t totally clear, but many believe it was due to political differences between the inventor and the chief of the Ordnance Department, General William Crozier. Believe it or not, some military leaders didn’t think the machine gun would be useful on the battlefield.

Whatever the reason, Lewis grew tired of being ‘slapped by rejections from ignorant hacks,’ and left the Army. After his retirement, he moved to Belgium in 1913, where he founded Armes Automatique Lewis to produce his gun. Later, the Birmingham Small Arms Company Limited (BSA) would help with production of the gun and ultimately purchase a license to produce the gun.

The distinctive Lewis Gun.
The distinctive Lewis Gun. Wikimedia Commons

The Lewis utilized excess gas left over from the combustion of a round to drive a piston contained within the receiver to the rear, where it would rebound against a spring. This process should sound pretty familiar.

A post was attached to the piston followed a helical track in the bolt, rotating it near the breech and forcing the three lugs at the rear of the bolt to lock into recesses in the gun’s body. The firing pin was affixed to this post, striking the round’s primer through a hole in the bolt. Of note is the shape of the spring: in lieu of a typical helical-coiled spring, the Lewis used a spiral spring suck as the ones the ones used in clocks. The spring could even be wound to alter tension.

A close-up of the Lewis Gun's pan magazine.
A close-up of the Lewis Gun’s pan magazine. Wikimedia Commons

An aluminum shroud covered the barrel, drawing air over the barrel’s radially finned aluminum heat sink to cool it and negating the need for a water jacket.

But perhaps the most striking feature of the Lewis was its top-mounted pan magazine, which held 47 or 97 rounds depending on make. Shaped similarly to a drum magazine, the pan held the rounds with their noses pointing inward. But drum magazines hold the rounds parallel to the axis and are fed by spring tension, while pan magazines are mechanically indexed. A cam on top of the gun’s bolt actuated a pawl mechanism via a lever. This arrangement provided a rate of fire of about 500 rounds per minute.

the first successful firing of a machine gun from an airplane in June of 1912.
Captain Charles Chandler (with prototype Lewis Gun) and Lt Roy Kirtland in a Wright Model B Flyer after the first successful firing of a machine gun from an airplane in June of 1912. Wikimedia Commons

Belgium was the first to use the Lewis Gun, chambered in .303 British. The gun saw its first taste of battle in skirmishes against the Germans in late 1914. The Lewis saw more extensive use on the Western Front with the British Army, replacing the heavier Vickers machine gun with the 28-pound Lewis in 1916, though it had officially adopted the weapon in 1915.

Later versions of the Lewis were used extensively on British and French aircraft during the First World War. In fact the Lewis was the first machine gun fired from an airplane, with Captain Charles Chandler of the U.S. Army firing a prototype from the foot-bar of a Wright Model B Flyer on June 7, 1912.

Despite the proven track record, the bad blood between Lewis and General Crozier prevented it from being adopted by the U.S. Army during the WWI. So deep was the feud that Lewis Guns were taken away from U.S. Marines arriving in France, instead replacing them with the underperforming Chauchat light machine gun.

After an impressive demonstration, the Army officially adopted two of John Moses Browning’s designs: the M1917 machine gun and the M1918 Browning Automatic Rifle.

A Marine field-tests the Lewis Gun in 1917.
A Marine field-tests the Lewis Gun in 1917. Wikimedia Commons

The U.S. Navy and Marines Corps did eventually find an official spot for the Lewis, manufactured by Savage in .30-06. It didn’t see much service in the hands of U.S. troops during WWI, but the Lewis managed to be one of the few machine guns that survived the interwar period before the second global conflict, and was pressed into service when U.S. forces entered WWII.

The gun could be found on armed merchant cruisers, small auxiliary ships, landing craft and submarines in the Navy fleet. The Lewis was also employed as a deck gun by the Coast Guard, and despite General Crozier’s objections, the Army did adopt the gun for aircraft use.

Browning M1917 Machine Gun

The water-cooled Browning M1917 machine gun.
The water-cooled Browning M1917 machine gun. Wikimedia Commons

John Moses Browning began work on the M1917 around 1900, when he filed a patent for the recoil-operated automatic weapon. The belt-fed gun consumed .30-06 cartridges at a rate of about 450 rounds a minute. In testing, the M1917 fired continuously for 48 minutes and 12 seconds, cranking out over 21,000 rounds without issue. The Army adopted the M1917 as its primary heavy machine, but manufacturing issues plagued the program. When the gun made it to the Western Front World War I was nearly over.

Val Browning, the inventor's son, demonstrates the M1917. He instructed U.S. troops in France on how to use the new gun.
Val Browning, the inventor’s son, demonstrates the M1917. He instructed U.S. troops in France on how to use the new gun. Wikimedia Commons

The M1917 wasn’t perfect, however, with the receiver suffering from structural integrity issues. Under heavy use, the bottom plates would free themselves from the dovetails holding them to the sides of the receiver. A stopgap measure was to rivet a horseshoe-shaped steel bracket to back of the receiver. Later, right-angled steel pieces were riveted to the bottom and side plates. The sides were also known to bulge, which was likely a result of hammering the dovetails shut. These issues led to the creation of the M1917A1.

A new bottom plate was developed by the Ordinance Department in the 1930s. This plate featured flanges that came up on both sides of the receiver, anchored by rivets, to solve the previous issues. The Rock Island Arsenal led the charge to convert existing M1917 to the new M1017A1 configuration, but the project was too large for just one armory, so others chipped in as needed. The rear sights were also modified, with removal the WWI-era multiple-aperture disk. They were converted from meters to yards in the process.

An M1917A1 in the Hackenberg museum, Veckring, Moselle, France.
An M1917A1 in the Hackenberg museum, Veckring, Moselle, France. Wikimedia Commons

To handle the stress of feeding an ammo belt from the ground, a new, stronger feed pawl pivot arm was installed. To alleviate issues that caused by the soft composition of the brass water jacket, Rock Island developed an all-steel version around 1943 that was backwards compatible. Beginning in 1938, the top pivot was swapped with a positive-locking hinge pin that held the top cover open so it wouldn’t close on one’s hands while working on the gun.

The Model 1917A1 saw service in World War II. Recently introduced armor-piercing ammunition extended the usefulness of the gun against hardened targets and vehicles. The 1917A1 was not svelte weapon by any stretch of the imagination, so it was generally relegated to use in a fixed defensive position, or as a battalion or regimental support weapon.

A U.S. Marine firing a Browning M1917 at the Japanese at the Battle of Iwo Jima.
A U.S. Marine firing a Browning M1917 at the Japanese at the Battle of Iwo Jima. Wikimedia Commons

The U.S. Army’s 5th Cavalry machine gunners killed several hundred Japanese in one night using their M1917A1s at the battle of Momote Airstrip in the Admiralties, greatly advancing the Allies cause in the Pacific Theater. As a memorial, one gun was left in position after the fierce battle. Some of the redesigned guns were sent to England for use by the Home Guard, since their stock of.303 Vickers were needed to resupply the equipment abandoned during the Fall of France.

M1918 Browning Automatic Rifle (BAR)

The M1918A2 Browning Automatic Rifle.
The M1918A2 Browning Automatic Rifle. Wikimedia Commons

John Moses Browning invented many firearms that have greatly impacted firearm design for generations after his passing. Perhaps the top three are the 1911 semiautomatic pistol, the A5 semi-auto shotgun, and the selective fire Browning Automatic Rifle, or BAR. The BAR introduced the world to “walking fire,” as a shoulder sling could support the 16-pound weapon while the operator advanced through a trench. John Moses’ son, Second Lieutenant Val Allen Browning, was the first to use the BAR in conflict in France on September 13, 1918.

A live fire demonstration of the BAR in front of military and government officials.
A live fire demonstration of the BAR in front of military and government officials. Wikimedia Commons

The BAR had a major impact on the first war, despite being introduced so late. Immediately after Browning debuted the gun to military brass it was awarded a contract. Because they were pressed into production so quickly, manufacturing issues plagued the first run. After the manufacturing kinks were ironed out, Browning sought to continue to improve the gun.

The M1918A1 was approved on June 24, 1937. The aim of the upgraded BAR was increased control of the weapon when fired in auto and bursts. To that end, a lightweight spiked bipod with adjustable legs was fitted to gas cylinder and a hinged steel butt plate was added. Despite being well received, limited numbers of the existing guns were upgraded to the M1918A1 configuration.

Second Lieutenant Val Browning with a BAR in France.
Second Lieutenant Val Browning with a BAR in France. Wikimedia Commons

The Army wanted the BAR to function as a squad automatic weapon, though that term had yet to be coined, so Browning went back to the drawing board in 1938. The first iterations of the M1918A2 design featured a barrel-mounted bipod as well as a FN-designed pistol grip and rate of fire reducer. The latter two modifications were scrapped when the Army declared that all of the alterations must be backward compatible with older versions of the BAR so that they may be retrofitted as the elder guns wore out. Springfield Armory stepped in with another rate-reducer mechanism that could be housed in the butt stock. This device provided two rates of automatic fire, selected by engaging a toggle.

To better fit the role of squad light machine gun a monopod was attached to the buttstock and a skid-footed bipod was mounted to the muzzle, which was also fitted with a new flash suppressor. To increase accuracy with the newly standardized M2 ball ammunition, a lighter .30-06 round with a flat base, fully adjustable iron sights with recalibrated rear scales were installed. To facilitate easier reloads magazine guides were added to the front of the trigger guard. A heat shield was added to help the cooling process and the hand guard was shortened. Eventually a carry handle was mounted to the barrel to ease movement through the battlefield.

Variants of the M1918.
Variants of the M1918. Wikimedia Commons

The M1918A2 saw plenty of service in World War II as a light machine gun. Each was employed with a team of three to aid in reloading and carrying ammunition. Unfortunately, the BAR didn’t prove to be as successful as a squad automatic weapon as it did in the trenches of WWI. The thin-profile barrel heated up quickly and lacked the ability to be swapped quickly, which severely limited its firepower. The use of magazines—the maximum capacity of which was 20 rounds—versus belts also kept rate of fire down.

The rate-reducer mechanism would often malfunction in the field when regular cleanings weren’t possible. The bipod and butt rest were often removed as they didn’t provide any accuracy advantage in battle and added weight. Soldiers also sometimes removed the flash hider to save weight. In practice, the M1918A2 devolved into the shoulder-fired automatic rifle that proved itself in World War I.

Browning M1919 Machine Gun (1919)

The air-cooled M1919 Browning machine gun.
The air-cooled M1919 Browning machine gun.

The M1919 is essentially an evolved M1917. The barrel was switched to an air-cooled configuration, eliminating some weight and the need to carry around a tank of water hooked to the cooling jacket with a hose.

While the water jacket kept barrels cool through prolonged strings of fire, they were vulnerable to puncture from enemy fire and shrapnel. Loss of the cooling effect of water renders the thin barrel near useless very quickly. This meant the jackets were often armored, adding more weight to the gun. And at eight pounds a gallon, the tank itself certainly placed a burden on those who had to carry and move it.

Even though the air-cooled barrel on the M1919 was heavier, it still represented a significant weight savings when compared with all the components of the water-cooled system.

There were a few variations of the M1919 to hit the battlefield, each building off the success of the previous models. The first, the M1919, was designed for tank use. As such, it didn’t feature sights. The M1919A1 was conceived for infantry use, with a bipod and a slightly lighter barrel. Sights were added as well. The M1919A2 was purpose-built for cavalry units, with an 18-inch barrel and a tripod, with cross compatibility with the earlier M1917 tripods. In 1931, an improved version of this gun was introduced for members of the infantry, dubbed the M1919A3.

U.S. soldiers fire a M1919A4 in Aachen, Germany.
U.S. soldiers fire a M1919A4 in Aachen, Germany. Wikimedia Commons

But it was the M1919A4 that saw the most production. The short barrels of the previous versions were good for mobility, but were known to fail to produce enough recoil to cycle the action reliably. The barrel was given a heavier contour and lengthened to 24 inches, as well as being fitted with a muzzle device, known as the barrel bearing, to increase recoil energy.

A buffer assembly was added to the backplate to reduce the effects of the bolt’s impact. The M1919A4 was used in both fixed and flexible mounts, by infantry and on vehicles. To make it easier to mount on vehicles, the front sight was moved from the barrel jacket to the receiver. An extended charging handle was added to some M1919A4s, which became known as the M1919A4E1. Those built from scratch with the extended charging handle were known as M1919A5.

A U.S. soldier takes aim with a tripod-mounted M1919A4 in Korea, 1953.
A U.S. soldier takes aim with a tripod-mounted M1919A4 in Korea, 1953. Wikimedia Commons

As World War II raged on, it became apparent that the Army’s attempt to use the BAR as a light machine gun was a failed endeavor. To remedy the mistake, they modified the M1919 yet again. The M1919A6 was created with a removable shoulder stock and a lighter barrel that reduced the recoiling mass for greater reliability. This eliminated the need for the barrel bearing, and permitted installation of wrench flats on the muzzle.

This facilitated quicker removal and installation of barrels. And the rapid swap of the lighter barrels was necessary because they did a poor job of cooling. The development of the M1919A6 was largely a stopgap measure, as the gun was heavier than many World War I-era machine guns. Still, the gun saw plenty of action toward the end of WWII, giving company commanders automatic fire support. Despite its shortfalls, the M1919 and its variants saw service with the U.S. military through the Korean War.

M2 Browning (1933)

The Browning M2HB Heavy Machine Gun.
The Browning M2HB Heavy Machine Gun. Wikimedia Commons

Another of John Browning’s brainchildren, the “Mah Deuce” is perhaps one of the most recognizable machine guns of all time, and one of the most long lived. Once again, he built off the successful M1917 action, but this time he swapped the .30-caliber barrels for one capable of propelling .50-caliber bullets.

The cartridge was designed alongside the gun itself, as such it was designated .50 BMG for Browning Machine Gun. The gun has been in continual service with U.S. and NATO forces since its development in the 1930s, proving successful in infantry, lightly armored vehicles, and anti-aircraft roles. Since its inception, the M2 has been a staple of vehicle armament.

Around the end of World War I, commander of the American Expeditionary Force John J. Pershing requested a large-caliber machine gun to deal with the increasing presence of armored vehicles. He asked the Ordnance Department to deliver a gun with a bore of at least half an inch and a muzzle velocity of 2,700 feet per second or better.

The Ordnance Department ordered a number of experimental Colt machine guns rechambered for the French 11 mm cartridge, but they were found to be ineffective because they lacked the muzzle velocity needed to pierce armor. John Browning began work on a .50 caliber machine gun around 1918, with the first trials taking place in October of that year. The gun was considered a failure because it fired less than 500 rounds per minute and had a muzzle velocity of only 2,300 feet per second, which was too slow to penetrate armor.

A U.S. soldier in Normandy stands guard with the M2HB installed on a dual-purpose mounting.
A U.S. soldier in Normandy stands guard with the M2HB installed on a dual-purpose mounting. Wikimedia Commons

Collaboration between John M. Browning and Fred T. Moore lead to the creation of the M1921, a water-cooled .50-caliber gun. An aircraft version of the same gun was also built. Shortly after, the world lost one of its greatest firearm inventors when Browning died in 1926.

After Browning’s death, Dr. S.H. Green examined the deficiencies of the M1921, as perceived by the military, and improved on its design. The result was a Swiss Army Knife of a machine gun receiver, capable of being turned into seven different guns by changing jackets, barrels, and other components. The receiver even permitted feeding of the disintegrating ammo belt from the left or right side by repositioning a handful of components. The gun was given the M2 moniker.

Audie Murphy fires a Browning M2HB in *To Hell And Back* (1955).
Audie Murphy fires a Browning M2HB in To Hell And Back (1955).

Colt began manufacturing the M2 prototypes in 1933, and eventually built an air-cooled variant. These served as a proof of concept, but the barrels would only stand up to about 75 rounds fired in rapid succession before they would fail from overheating. The next model would be known as the M2 HB, with latter standing for Heavy Barrel. This barrel had a much heavier contour than the previous version, and somewhat made up for the lack of coolant.

Failures would still occur, as with all machine guns pushed too hard, so a quick-change barrel system was devised. The switch from water to air cooling increased the guns usefulness on the ground, as crews only had to lug around 84 pounds, as opposed to the 121 pounds of the water-cooled model.

An even lighter version with a thinner profile barrel weighing only 60 pounds was built for aircraft use, dubbed the Army/Navy model, designated as the AN/M2. This would go on to replace the .30 caliber guns of Browning’s earlier design in nearly every American aircraft of the WWII era.

An M2 Browning overlooking the Korengal Valley at Firebase Phoenix, Afghanistan, in 2007.
An M2 Browning overlooking the Korengal Valley at Firebase Phoenix, Afghanistan, in 2007. Wikimedia Commons

Interestingly, the M2HB is also capable of shooting in semi-auto. Two rates of automatic fire are available: high speed, with over 40 rounds per minute; or low speed, less than 40. This translates to a rate of fire of 450-575 rounds per minute. Five to seven round bursts are considered optimal, as sustained fire at high rates will wear out the bore within a few thousand rounds.

The range of the gun is around 2,000 yards, but skilled operators can hit targets as far as 2,200 yards with a bit of luck. Perhaps this is why the gun existed in the same form for nearly 70 years. It received a facelift and a new designation, M2A1, in 2012. The M2A1 uses an improved bolt assembly, a new flash suppressor, carry handle, and manual trigger block safety—an item that probably should have been standard equipment all along. All of the approximately 45,000 existing M2HB in U.S. Army service machine guns are set to be updated.

In 1967, U.S. Marine sniper and legend Carlos Hathcock set a record for the longest sniper kill that would last for decades, and he did it with an M2 Browning firing in semi-auto fitted with a telescopic sight at a range of 2,500 yards. The record stood until 2002, when it was broken by Canadian snipers Rob Furlong and Arron Perry during the War in Afghanistan. Hathcock wasn’t the only one to use the M2 in a sniping role, leading to the adoption of the .50 BMG as a viable sniper round.

The M2 has been on the battlefield during WWII, the Vietnam War, the Korean War, Gulf Storm, and the War on Terror, along with every other conflict the U.S. has been a part of since 1933, not to mention the use it saw as part of other militaries around the world.

M1941 Johnson Light Machine Gun (1940)

The M1941 Johnson Light Machine Gun.
The M1941 Johnson Light Machine Gun. Wikimedia Commons

The M2 is remarkably well known because its design has withstood the test of time, with a career spanning generations. The M1941 Johnson Machine Gun, also known as the Johnny Gun, isn’t as well known, likely because its service life was a mere blip in comparison.

Melvin Johnson Jr., a lawyer and Captain in the Marine Corp Reserves, designed the M1914 Johnson LMG after he created the semiautomatic M1941 Johnson Rifle. While the Johnson rifle was an innovative design with a rotary magazine, the United States armed services passed over it in favor of the M1 Garand. A handful saw battle, however, with one being used famously by Medal of Honor Recipient USMC Captain Robert Hugo Dunlap in the Battle for Iwo Jima.

The light machine gun shared a number of parts with the semiautomatic rifle, including the short recoil action and the rotating bolt. Unlike the rotary magazine on the rifle, the LMG fed from either a single-column 20-round magazine or a stripper clip placed at the ejection port to recharge the mag in place. In a pinch, single rounds could also be loaded through the breech. The rate of fire could be adjusted anywhere from 200 to 600 rounds per minute, which helped keep barrel temperatures down.

The LMG had some additional features that the rifle lacked, such as a barrel-mounted bipod. This would prove to undesirable, as it needed to be removed for a barrel swap. Later versions of the gun, the M1944, would have a unique folding monopod that utilized two wings to stabilize the gun. It could also be used as a pistol grip in the forward assist position, with the wings serving as a heat shield to protect the operator’s hands. The 1944 iteration swapped the wooden furniture for metal tubing and butt plate.

Ten Johnny Guns so configured were provided for testing in the end of 1943. Unfortunately, these guns all succumbed to the elements at the Aberdeen Proving Grounds. Later testing conducted by the Marine Corps Equipment Board at Quantico would see the LMG perform more favorably—so much so that the Corp sought to replace their aging BARs with the new gun. Unfortunately for Johnson, the Marine Corps Commandant rejected the request, fearing that the Army’s decision to not adopt the gun would lead to complications for the armorers.