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The U.S. Army writes:

The M2 Machine Gun or Browning .50 Caliber Machine Gun is a heavy machine gun designed towards the end of World War I by John Browning. Its design is similar to Browning’s earlier M1919 Browning machine gun, which was chambered for the .30-06 cartridge. The M2 uses the much larger and much more powerful .50 BMG cartridge, which was developed alongside and takes its name from the gun itself (BMG standing for Browning Machine Gun). It has been referred to as “Ma Deuce”, in reference to its M2 nomenclature. The design has had many specific designations . . .

the official designation for the current infantry type is Browning Machine Gun, Cal. .50, M2, HB, Flexible. It is effective against infantry, unarmored or lightly armored vehicles and boats, light fortifications and low-flying aircraft. The M2 machine gun has been produced longer than any other machine gun.

The Browning .50 caliber machine gun has been used extensively as a vehicle weapon and for aircraft armament by the United States from the 1930s to the present. It was heavily used during World War II, the Korean War, the Vietnam War, the Falklands War, the Iraq War and the War in Afghanistan in the 2000s and 2010s.

It is the primary heavy machine gun of NATO countries, and has been used by many other countries. The M2 has been in use longer than any other small arm in U.S. inventory except the .45 ACP M1911 pistol, also designed by John Browning.

The current M2HB is manufactured in the U.S. by General Dynamics and U.S. Ordnance for use by the U.S. government, and for allies via Foreign Military Sales.


Machine guns were heavily used in World War I, and weapons of larger than rifle caliber were appearing. Both the British and French had large caliber machine guns. The larger rounds were needed to defeat the armor that was being introduced to the battlefield. Armor was also appearing in the skies. During World War I, the Germans introduced a heavily armored airplane, the Junkers J.I. The armor made aircraft machine guns using conventional rifle ammunition (such as the .30-06) ineffective.

Consequently, the American Expeditionary Force’s commander General John J. Pershing asked for a larger caliber machine gun. Pershing asked the Army Ordnance Department to develop a machine gun with a caliber of at least 0.50 inches (12.7 mm) and a muzzle velocity of at least 2,700 feet per second (820 m/s).

U.S. Col. John Henry Parker, commanding a machine gun school in France, observed the effectiveness of a French 11 mm (0.43 in) incendiary armor-piercing round. The Army Ordnance Department ordered eight experimental Colt machine guns rechambered for the French 11-mm cartridge. The French had developed a prototype machine gun for an even larger caliber.

The French 11-mm round was found to be unsuitable because its velocity was too low. Pershing wanted a bullet of at least 670 gr (43 g) and a muzzle velocity of 2,700 ft/s (820 m/s). Development with the French round was dropped.

Around July 1917, John M. Browning started redesigning his .30 caliber machine gun for a larger caliber. Winchester worked on the cartridge, which was a scaled-up version of the .30-06. Winchester initially added a rim to the cartridge because the company wanted to use the cartridge in an anti-tank rifle, but Pershing insisted the cartridge be rimless.

The first .50 machine gun underwent trials on 15 October 1918. It fired at less than 500 rounds per minute, and the muzzle velocity was only 2,300 ft/s (700 m/s). Cartridge improvements were promised. The gun was heavy, difficult to control, fired too slowly for anti-personnel, and was not powerful enough against armor.

While the .50 was being developed, some German anti-tank rifles and ammunition were seized. The German rounds had a muzzle velocity of 2,700 ft/s (820 m/s), an 800 gr (52 g) bullet, and could pierce 1 in (25 mm) at 250 yd (230 m). Winchester made the .50 caliber round have similar performance. Ultimately, the muzzle velocity was 2,750 ft/s (840 m/s).

Efforts by John M. Browning and Fred T. Moore resulted in the water-cooled Browning machine gun, caliber .50, M1921. An aircraft version was termed the Browning aircraft machine gun, caliber .50, M1921.

These guns were used experimentally from 1921 until 1937. They had light-weight barrels and the ammunition fed only from the left side. Service trials raised doubts whether the guns would be suitable for aircraft or for anti-aircraft use. A heavy barrel M1921 was considered for ground vehicles.

John M. Browning died in 1926. Between 1927 and 1932, Dr. S.H. Green studied the design problems of the M1921 and the needs of the armed services. The result was a single receiver design that could be turned into seven types of .50 caliber machine guns by using different jackets, barrels, and other components.

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  1. Thanx for the video. Dumb question time. Does the rear door gunner have a safety strap or does his sheer bad-assery keep him in place? His perch looks very precarious.

  2. Design your weapons big enough to be durable and reliable under the worst conditions, then double the dimensions. You gotta love the J.M. Browning weapon design theology. And yes, it IS a theology.

    • Even firing .50 caliber rounds 600 times a minute, she would be less destructive than the human candidates on the ballot.

    • Along with the recent states voting rifles as “The State Gun of —–“, (One of which was the Barett in .50 BMG, as I recall.) maybe we should lobby Congress to vote the Ma Deuce Browning M2 as the National Gun of The United States of America. At the very least it would be amusing to see what happened when the bill landed on Obama’s desk.

  3. Out of all my experiences in the Army, riding behind an M2 was by far my favorite. As soon as I got to my first duty station, I started pestering my platoon sgt. mercilessly to get qualified on the M2, and he finally gave in shortly before my first deployment. It was totally worth it. I’d jump at a chance to do it again.

  4. Oh look. Operational ones.

    The confidential independent study ordered by the Marine Corps found a litany of issues, including the fact that force size has dropped to just 146 Super Stallions—50 less than what is needed. If the U.S. were to go to war, even in a limited fashion, nearly every airframe would have to deploy. This leaves nothing for stateside training, contingency operations or war reserve.

    Making matters worse, major parts shortages and years of deferred maintenance plague the fleet. Most astonishingly, this has led to a readiness of just 23 percent. This is less than one third of the Pentagon’s general readiness target of 75 percent for its military aircraft.

    With a readiness rate of just 23 percent and just 146 CH-53Es in inventory, only 33 aircraft are actually available at any given time.

    • We would have plenty of money to pay for all the necessary parts/repairs to get all those birds battle ready if we would just stop giving all our money away to freeloaders within and beyond our borders.

  5. I have seen reference to a .60 caliber version and even a suggestion of a .70 was in the planning stages to be used on fighter aircraft. I suspect lots of ideas have been tried.

  6. I remember reading the book Chickenhawk years ago. If my memory is correct, they mounted an M2 on a Huey but the recoil was too great for the air frame. Too bad!

  7. That is a great tip especially to those fresh to the blogosphere.
    Simple but very accurate information… Appreciate your sharing this
    one. A must read post!


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