M2 HB

Summary

Country	🇺🇸 United States
Category	Machine gun
Manufacturer	Browning

Technical specifications

M2 HB
Fire Rate	450 - 600 rounds/min.
Caliber	.50 BMG (12,7 x 99 mm)
Magazine	belt of 100 rounds
Length	1650 mm (65.0 in)
Weight	38.0 kg (83.8 lb)
Range	1200 m (3937 ft)

Description

The M2 machine gun, informally known as "Ma Deuce," is a heavy machine gun designed by John Browning near the end of World War I. It was developed to meet General John J. Pershing's requirement for a larger caliber machine gun capable of defeating armor, and utilized Browning's new .50 BMG (12.7 mm) cartridge, a scaled-up version of the .30-06. Initial trials in October 1918 highlighted areas for improvement, including rate of fire and armor penetration, informed by captured German 13.2mm rounds. Subsequent efforts by Browning and Fred T. Moore resulted in the experimental M1921 water-cooled machine gun and an aircraft version. Following Browning's death in 1926, S. H. Green's work from 1927 to 1932 produced a versatile receiver design that could form the basis for various configurations, allowing for right or left-side feed. Colt began manufacturing the M2 with Navy support in 1933, and FN Herstal has produced it since the 1930s. Current manufacturers include General Dynamics, U.S. Ordnance, and Ohio Ordnance Works Inc. The air-cooled M2 HB (Heavy Barrel), with a thicker barrel, was developed, reducing the weapon's weight compared to the water-cooled M2. The M2HB's lengthy barrel change procedure later prompted the development of the quick change barrel (QCB) system.

The Browning M2 is an air-cooled, belt-fed machine gun operating on the short recoil principle from a closed bolt. It is a scaled-up adaptation of Browning's M1917 .30 caliber machine gun. Firing the .50 BMG cartridge, it offers substantial range, accuracy, and stopping power. The closed bolt allows for synchronization, historically useful on aircraft. Cyclic rates vary by model: the M2HB ground gun fires 450–575 rounds per minute, early water-cooled AA guns had rates around 450–600 rpm, while aircraft versions like the AN/M2 achieve 750–850 rpm, and the AN/M3 reaches 1,200 rpm. The M2HB permits selectable single shots or varying rates of automatic fire via burst modes. Its effective range is cited as 1,830 metres (2,000 yd), with a maximum effective range of 2,000 metres (2,200 yd) from the M3 tripod. In the M2HB ground role, the weapon weighs 84 pounds (38 kg), plus 44 pounds (20 kg) for the M3 tripod. Control is typically via butterfly triggers and spade handles, although modern upgrades feature squeeze triggers. The feed side can be changed from left to right by reconfiguring components. Ammunition types include standard ball, armor-piercing (AP), armor-piercing incendiary (API), and API-tracer (APIT). Modern types include M33 Ball, M17 tracer, M8 API, M20 API-T, and SLAP/SLAP-T rounds, which feature a tungsten penetrator capable of perforating significant armor at extended ranges. A large blank-firing adapter is required for firing blanks.

Variants of the M2 include:

• The original water-cooled M2

• The M2 HB (Heavy Barrel)

• Fixed and turret types

The M2 HB was developed into variants for use in vehicle turrets (e.g., M48 Patton, M1 Abrams) and naval vessels. A significant modern upgrade is the M2A1 (M2E2), which incorporates a quick change barrel with fixed headspace and timing, a flash suppressor, a modified bolt, and a manual trigger block safety. Aircraft-specific variants include the lightweight AN/M2, widely used in WWII US aircraft at higher cyclic rates (600–800 rpm), and the even faster-firing AN/M3 (~1200 rpm). Derivatives for specific aircraft or mounts include the M296 for the OH-58 helicopter (with adjustable rate), XM213/M213 for helicopter door guns, and lightweight versions like the GAU-15/A, GAU-16/A, and GAU-18/A for USAF helicopters. Modern M3 variants like the FN M3M have been adopted as the GAU-21/A by multiple nations and services, featuring a high rate of 1,100 rpm and improved barrel life. Foreign derivatives and licensed copies exist, such as the FN Browning M.1939 (using 13.2×99mm) adopted by Sweden (Akan m/39) and adapted by Finland (VKT 12,70 LKk/42), and the Chinese CS/LM6 clone.

The M2 machine gun has seen extensive operational service across numerous major conflicts since its introduction, including World War II, the Korean War, the Vietnam War, the Falklands War, the Gulf War, the Iraq War, and the War in Afghanistan. It is the primary heavy machine gun used by NATO countries and has been adopted by many nations globally, serving U.S. forces longer than any firearm except the M1911 pistol. It has fulfilled roles ranging from anti-personnel, anti-light vehicle, anti-watercraft, anti-fortification, and anti-low-flying aircraft weapon. During World War II, it was widely employed on aircraft, vehicles, and as a ground-mounted weapon by the United States and its allies, demonstrating effectiveness against German vehicles and low-flying aircraft. The M45 Quadmount, combining four M2HB guns, was particularly effective in both anti-aircraft and later anti-personnel roles. The M2HB was utilized in conflicts through Vietnam and into the 21st century, notably in urban combat environments. It has been used by Commonwealth forces since World War II, integrated onto vehicles and aircraft, and saw action in later conflicts including the Battle of Mirbat and the Falklands War. The Israel Defense Forces have used the M2 in all their conflicts, including upgrading to the M2HQCB version, deploying it as an infantry weapon, on tanks, and naval vessels. Nigerian forces employ it in counterinsurgency operations. Imperial Japan developed and used derivatives during World War II. Post-war, Japan license-produced the M2HB, deploying it across the Japan Self-Defense Forces on vehicles, for anti-aircraft defense, and on patrol vessels. The M2 has also been employed as an improvised long-range sniper rifle, achieving notable engagements in the Korean and Vietnam Wars.