The Browning M2 .50 Caliber Machine Gun, Heavy Barrel (called "Ma Deuce") is an automatic, recoil operated, air-cooled machine gun with adjustable headspace. The M2 is crew transportable with limited amounts of ammunition over short distances. By repositioning some of the component parts, ammunition may be fed from either the left or right side. A disintegrating metallic link-belt is used to feed the ammunition into the weapon. .50 cal. ammunition for infantry use is provided on 100 round belts packed into steel ammo boxes.
The M2 has a back plate with spade grips, trigger, and bolt latch release. The gun is equipped with leaf-type rear sight, flash suppressor and a spare barrel assembly. Associated components are a tripod and mounts for virtually any vehicle, aircraft, or naval vessel. The M2 is effective against targets that include personnel, aircraft, or equipment even if lightly armored.
Over the years since its introduction, the M2 .50 cal. machine gun had been manufactured by a number of different suppliers, most recently Saco Defense.
Browning machinegun, Cal. .50 HB, M2 on turret of M-7 Priest Motor Gun Carriage, Iron Mountain, CA, during World War II. The M-7 Priest mounts a 105mm howitzer as its main gun.
Today in WW II: 26 Jul 1941 Major Gen. Douglas MacArthur, retired US Army Chief of Staff, recalled to active duty, assigned to mobilize the Philippine Army and strengthen the US garrison in the Philippine Islands. More↓
The .50 cal. machine gun was developed by John M. Browning at the request of the U.S. Army. Experience in France in 1917 showed the need for a heavy machine gun that could act against aircraft (fixed wing and balloons), tanks, and other armored vehicles that were then first appearing on the battlefield. Starting in July 1917, the Browning .30-06 machine gun was scaled up and reinforced to handle a .50 cal. cartridge, in experimental development from ideas used in a French 11mm machine gun. The first .50 cal. prototype was assembled by Browning at the Winchester plant on 12 November 1918 and Winchester went on to produce a total of six models for testing. However, Infantry tests were unsatisfactory, finding that the bullet lacked range and penetration while the gun was unstable in automatic firing.
The technical problems of the new .50 cal. machine gun were overcome when a captured German 13.2mm anti-tank rifle and its ammunition gave the Winchester engineers the ideas needed to complete the .50 cal. cartridge development with performance satisfactory to the Army. The completed Winchester-designed cartridge was taken to Frankford Arsenal (Philadelphia, PA) in 1918 for production. The prototype .50 cal. machine gun was altered and upgraded to work properly with the new .50 caliber round, resulting in the standardized .50 cal. United States Machine Gun M1921, adopted for use on aircraft in 1923. After a series of .50 cal. water-cooled, aircraft and tank models were tested in the 1920s, an improved version of the M1921 was adopted in 1933 as the air-cooled Browning Machinegun, Caliber .50 HB, M2.
Subsequent models of the M2 .50 cal., using the same receiver, were adopted by the various services in both air-cooled and water-cooled versions for use by infantry, aircraft, tanks, and otehr applications. During World War II, nearly two million M2 machine guns of all variations were produced.
The M2 .50 cal. Machine Gun went out of production in the 1970s, and by the early 1990s the capability to manufacture the M2 barrel had virtually disappeared from the U.S. industrial base. An Army inventory of 13,000 "unserviceable" M2s were stockpiled, although they required some level of repair or maintenance before they could be used. With combat operations in Iraq and Afthanistan, the Army identified a requirement for an additional 8,000 M2s for fielding in FY2005. During the summer of 2004, Anniston Army Depot began to repair M2s at the rate of 100 per month, with a ramp up to 700 per month by early 2005, once new barrels and other parts were procured.
M2 .50 cal. Machine Gun Mountings
Ma Deuce Browning machinegun, Cal. .50 HB, M2.
When mounted in a four-gun configuration, the M2 was known as the Quad-50, a highly effective anti-aircraft weapon in World War II, also used extensively in Korea and Vietnam for anti-personnel purposes.
Single mounts are available for ground use (Tripod Mount, M3), antiaircraft (Antiaircraft Mount, M63), or vehicles (Truck Mount, M36 [ring] and Pedestal Truck Mount M31C or M24A2 [posts]). Other mounts are used in tanks, aircraft, naval vessels or other purposes.
M2 HB (Enhanced) .50 caliber Machine Gun (M2E2)
The M2HB (Enhanced), called the M2E2, combines the proven performance and logistics support of the existing M2HB machine gun with new features and design improvements including:
Fixed headspace and timing configuration (eliminates safety concerns associated with barrel changing)
Quick-change barrel (QCB) system
Removable barrel handle to simplify hot-barrel changing
The manual safety makes the M2E2 easier and safer to use, including the ability to move the weapon with a chambered round. The new flash hider reduces muzzle flash, making the M2 night-vision friendly. A patented, J-slot barrel retention system ensures secure barrel locking and alignment. Common barrel thread interchanges with existing HB barrels, eliminating logistics concerns during fielding and simplifies conversion of existing M2HB barrels to the QCB configuration. In fact, all the upgrades can be fitted to existing M2HB weapons.
General Dynamics Armament and Technical Products, who manufactured the M2HB for 25 years, developed the M2E2 version. Fielding began in 2005 in the form of kits for the Army to use to overhaul 100 M2HB machine guns at Anniston Army Depot, AL.
Browning machinegun, Cal. .50 HB, M2 on M3 Tripod Mount.
Weight of receiver group
Weight of barrel
26 lbs (approx)
Weight of tripod mount, M3
44 lbs (w/elev mech & pintle w/bolt)
Total weight of gun complete, on M3 mount
126 lbs (approx)
Maximum range (M2 ball)
Maximum effective range
Cyclic rate of fire
450-500 rpm (approx)
Muzzle velocity (M2 ball)
2,930 fps (1,997 mph)
Length of gun, overall
65 in (approx)
Length of barrel
Tabulated data from FM 23-65, December 1955.
M2 .50 on U.S.Navy river patrol boat (PBR), Go Cong River January 1967.
Browning machinegun, Cal. .50 HB, M2 with night vision and other accessories.
Thanks to A1C Crouse for help with this page.
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