M2 Browning

The **M2 machine gun** or **Browning .50 caliber machine gun** (informally, "**Ma Deuce**") is a heavy machine gun that was 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 Browning's larger and more powerful .50 BMG (12.7 mm) cartridge. The design has had many designations; the official U.S. military 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 gun has been used extensively as a vehicle weapon and for aircraft armament by the United States since the 1930s. It was heavily used during World War II, the Korean War, the Vietnam War, the Falklands War, the Soviet–Afghan War, the Gulf War, the Iraq War, and the War in Afghanistan. It is the primary heavy machine gun of NATO countries and has been used by many other countries as well. U.S. forces have used the M2 longer than any other firearm except the .45 ACP M1911 pistol, which was also designed by John Browning.

The current **M2HB** (heavy barrel) is manufactured in the U.S. by General Dynamics Ohio Ordnance Works, and U.S. Ordnance for use by the U.S. government, and for allies via Foreign Military Sales, as well as by foreign manufacturers such as FN Herstal.

## Aircraft guns

### .50 Browning AN/M2

The M2 machine gun was widely used during World War II, and in later postwar conflicts, as a remote or flexible aircraft gun. For fixed (offensive) or flexible (defensive) guns used in aircraft, a dedicated M2 version was developed called the ".50 Browning AN/M2" or the "12.7 mm AN/M2". The "AN" stands for "Army/Navy", since the gun was developed jointly for use by both services. The AN/M2 designation was also used for other aircraft guns and therefore it is important to write the caliber before the designation.

The 12.7 mm AN/M2 had a cyclic rate of 600–800 rounds per minute, with the ability to be fired from an electrically operated remote-mount solenoid trigger when installed as a fixed gun. Cooled by the aircraft's slip-stream, the air-cooled 12.7 mm AN/M2 was fitted with a substantially lighter 36-inch (91 cm) length barrel, reducing the weight of the complete unit to 61 pounds (28 kg), which also had the effect of increasing the rate of fire. The full official designation for this weapon was "Browning Machine Gun, Aircraft, Cal. .50, AN/M2" (Fixed) or (Flexible).

The 12.7 mm AN/M2 was used on many aircraft during WWII, as it served as the main aircraft armament in the US military. Most US fighter aircraft were armed with four, six or eight AN/M2 MGs mounted in the wings. Some famous examples being the P-40, P-47, and P-51 for the USAAF and the F4F, F6F, and F4U for the US Navy. For bombers, the AN/M2 was used in both flexible and fixed positions for both offensive and defensive use. In flexible defensive positions, the B-17G Flying Fortress heavy bomber was armed with 13x AN/M2 guns in both turreted and flexible positions. In fixed offensive configurations, like on the B-25 Mitchell, commonly carried 6 to 12 fixed guns for strafing.

In foreign use the AN/M2 is often just referred to as the M2 Browning. In Sweden it was re-designated ***12,7 mm automatkanon m/45*** (short *12.7mm akan m/45*) meaning 12.7 mm autocannon m/45. Note the Swedish Air Force used a different designation system which recognized the incendiary rounds as grenades, thus it was called autocannon. The AN/M2 was also produced in Finland under the export name **Colt MG 53-2**.

### M296

The XM296/M296 is a further development of the AN/M2 machine gun for the OH-58 Kiowa Warrior helicopter. The M296 differs from previous remote firing variants in that it has an adjustable firing rate (500–850 rpm), while lacking a bolt latch (allowing single-shot operation). As an air-cooled gun used aboard a relatively slow rotary-wing aircraft, the M296 has a burst restriction rate of 50 rounds per minute sustained fire or 150 rounds per minute maximum while conducting peacetime training requirements; the combat firing rate is unrestricted but a ten-minute cooling period after prolonged firing is mandated to avoid stoppages due to overheating.

### XM213/M213, XM218, GAU-15/A, GAU-16/A, and GAU-18/A

The XM213/M213 was a modernization and adaptation of existing .50 caliber AN/M2s in inventory for use as a pintle-mounted door gun on helicopters using the M59 armament subsystem.

The GAU-15/A, formerly identified as the XM218, is a lightweight member of the M2/M3 family. The GAU-16/A was an improved GAU-15/A with modified grip and sight assemblies for similar applications. Both of these weapons were used as a part of the A/A49E-11 armament subsystem (also known as the Defensive Armament System).

The GAU-18/A is a lightweight variant of the M2/M3 and is used on the USAF's MH-53 Pave Low and HH-60 Pave Hawk helicopters. These weapons use the M2HB barrel and are typically set up as left-hand feed, right-hand charging weapons, but on the HH-60 Pave Hawks that use the EGMS (External Gun Mount System) the gun is isolated from the shooter by a recoil-absorbing cradle and all weapons are set up as right-hand charge but vary between left- and right-hand feed depending on what side of the aircraft it is on. A feed chute adapter is attached to the left- or right-hand feed pawl bracket allowing the weapon to receive ammunition through a feed chute system connected to externally mounted ammunition containers holding 600 rounds each.

### AN/M3, GAU-21/A, and M3P

During World War II, a faster-firing Browning was developed for aircraft use. The AN/M3 increased the rate of fire to around 1,200 rounds per minute while firing the same round with minimal change in weight or size. The AN/M3 was used in Korea on the P-51D-30, F-82 Twin Mustang (the XP-82 mounted a total of 14 AN/M3 machine guns), F-86 Sabre, F-84 Thunderjet, and F-80 Shooting Star, and in Vietnam in the XM14/SUU-12/A gun pod. Two are installed in the Embraer EMB 314 Super Tucano aircraft as a fixed wing-mounted standard weapon as designated as M3W with minor modification with reduced weight barrel, electronic box triggered from the cockpit with 250 rounds each.

The M3 series is used by the U.S. military in two versions, the M3M and M3P. The fixed, remote-firing version, the FN M3P, is employed on the Avenger Air Defense System and was used on the OH-58D, augmenting the XM296 .50 cal. machine gun. The M3M flexible machine gun has been adopted by USN under the designation GAU-21/A for use on helicopters. The GAU-21/A is also being used by the U.S. Marine Corps to upgrade from the XM-218/GAU-16 .50 cal. machine gun for the CH-53E, on the UH-1Y Venom, and on the Canadian Forces' CH-146 Griffon via the INGRESS upgrade.[*citation needed*] The Air Force is looking to replace the GAU-18 on the HH-60G Pave Hawk with the GAU-21 because of its higher 1,100 rpm rate of fire, longer 10,000-round barrel life, and lower recoil through the use of a soft mount. The M3M is also the primary machine gun used by the Royal Navy's Fleet Air Arm for helicopter armament on Wildcat and Merlin aircraft.