M2 .50 Caliber Machine Gun
John Moses Browning (1855-1926) of Ogden, Utah, is considered by many to be the greatest firearms designer ever to live. He invented many innovative and popular sporting and military weapons produced by his own company, as well as Winchester, Colt, and other domestic and foreign manufacturers. His military arms were credited, even by the enemy, with giving the United States and its allies weapons superiority in conflicts of the 20th century. Of the .50 caliber machine gun, German Field Marshal Herman Göring said, "If the German Air Force had had the Browning .50-caliber, the Battle of Britain would have turned out differently."
In April 1918, the American Expeditionary Force in Europe, in a cable to the War Department, expressed an urgent requirement for a high-powered, large-caliber machine gun and ammunition primarily for aircraft, with second priority for ground use. Available knowledge on the performance of a German 13.2mm rimmed antitank cartridge, as well as information on the British development of a caliber .50 cartridge, led to a decision to develop a caliber .50 machine gun and ammunition. Guns were subsequently designed under the supervision of John Browning at the Colt's Patent Fire Arms Manufacturing Company (ground type) and at the Winchester Repeating Arms Company (aircraft type). These weapons were designated as the .50 caliber M1918 and had a rate of fire of 500 rounds per minute. The ground type was a water-cooled weapon, while the aircraft type was air-cooled.
Improvements to these weapons resulted in the M1921 aircraft gun, actually standardized in 1923, and the M1921 water-cooled gun, which was officially
adopted in 1925. Only a small number of each were procured. These weapons had a nominal rate of fire of 500 to 6OO rounds per minute, but were handicapped by their being able to feed only from the left side.
In 1933, a further series of refinements resulted in the .50 caliber M2 machine gun, which had a water-cooled ground variant and an air-cooled aircraft variant as with the M1918 and M1921. New to the series was an air-cooled ground variant with a heavy barrel, designated as the Machine Gun, .50 Caliber, M2, Heavy Barrel and known more commonly as the M2 Heavy Barrel or M2HB. These three guns used the same basic receiver and included features originated by Dr. Samuel G. Green of the Ordnance Corps and others developed by the Colt Company for their commercial guns.
The belt feed mechanism of the M2 could use either woven fabric belts or disintegrating metallic links. Also, by repositioning a few parts, the weapon could be fed from either the right or left side, a major improvement over the M1918 and M1921. The weapon was so versatile that the US Army, Army Air Forces, and Navy all adopted it.
Innumerable variants and derivatives would be tested before, during and after the Second World War. The weapon and its derivatives would be used on a wide variety of ground vehicles, aircraft, and ships over the years, and after over 80 years in frontline service, it was still widely used around the world. One of the more notable of the derivatives was an aicraft gun designed to feature a higher rate of fire than the standard M2 aircraft guns. The ground variants of the M2 had a rate of fire of 450-550 rounds per minute, while aircraft guns had a rate of fire of 750-850 rounds per miunte. The new aircraft gun, eventually standardized as the M3, had a rate of fire over 1,000 rounds per minute. The weapon subsequently led to an entire new subset of derivatives.
The development of the M3, led to a number of features being incorporated into standard M2 aircraft guns. On 12 October 1944, Ordnance Committee action was taken to authorize the limited procurement of 31,336 of the guns, designated as the T36. This procurement was discontinued after approximately 8,000 guns had been produced because of the unexpected progress made in the development of the T25E3 high-speed gun, which led to its standardization as the M3 earlier than had been thought possible. Following the standardization of the M3 gun, the T36 gun was reclassified as limited standard, and redesignated Machine Gun, Caliber .50, M2A1 Aircraft, Basic. The success of the M3 meant that there was no further procurement of these guns.
In the period after the Second World War, a variant of the weapon for fixed use in vehicles was also developed. Intended as a coaxial weapon, the gun, designated M2E1, saw little usage, being interchanable in most cases with weapons of smaller caliber. The weapon was never type classified as standard and a fixed variant of the standard of the standard M2 was subsequently developed. Originally intended for the M48 tank and known as the M48 Turret Type, the new weapon remained in service and was later adapted to the M1 Abrams tank in the 1980s.
The M2 machine gun on the M3 tripod provided a very stable firing platform. Together with its slow rate of fire and its traversing and elevating mechanism, the M2 was used to a very limited extent as a sniper weapon during the Vietnam war at fixed installations such as firebases. Snipers prefired the weapons at identifiable targets and worked the data into range cards insuring increased first-round accuracy. The 1st Battalion, 5th Infantry, part of the 25th Infantry Division, constructed 20-30 foot high shooting platforms, adding steel base plates and posts to further stabilize the M2 on the M3 tripod. Together with the use of so-called "Starlight" night vision scopes, the M2 severely limited enemy movement within 900 yards (800 meters) of the perimeter of a firebase.
Also during the conflict in Vietnam, a number of M2 aircraft machine guns were refurbished and fitted with spade grips for flexible use as part of the M59 armament subsystem for the UH-1 series of helicopters. The M213 had a rate of fire of 750-800 rounds per minute, similar to the original M2 aircraft guns. The M213 was type classified standard B, substitute standard, and a total of 360 units were built.
By 2005, a number of issues became apparent with the existing M2 machine gun. A requirement for an enhanced M2 .50 caliber machine gun, initially referred to as the M2E50, was developed. The new weapon would limit the soldier's exposure time to enemy fire while changing the barrel and setting headspace and timing of the weapon. As of 2005, the desired features included: Fixed headspace, Vortex flash hider to reduce signature; improved carrying handle; MIL-STD-1913 rails to mount optics; and a safety switch.
In December 2006 an Approved Capabilities Production Document was issued for a product improvement of the .50 caliber M2 machine gun. A Release Request for Proposal was issued in October 2007 for what had become formally designated as the M2E2, with the bid samples being recieved in November 2007. Testing was performed between November and June 2007 at Aberdeen Proving Grounds, Maryland. An Engineering Change Proposal (ECP) was approved for FY07 M2 production to allow for the incorporation of a number of improvements then in development. It was hoped in May 2008, that by July 2008, a single vendor for what was also being referred to as the Quick Change Barrel (QCB) Kit would be selected.
As of May 2008, the enhancements included incorporating a trigger block to the weapon's back plate assembly to prevent inadvertent firings. A trigger and bolt latch release would be replaced on back plates with interference. All future production would also contain trigger blocks. Thermal Weapon Sight brackets (TWS with side rails) were provided to PM Sensors and Lasers for fielding during testing and there was a plan to change the rear sight markings from yards to meters. PM Crew Served Weapon was also investigating material change of the headspace and timing gages for existing weapons to lower cost, increase corrosion resistance and dimensional stability. Production Verification Tests of the M2E2 kit at Aberdeen Test Center were conducted between May and October 2009. A Limited User Evaluation at Fort Benning, Georgia was also conducted in July 2009.
General Dynamics Armament and Technical Products of Burlington, Vermont was awarded on 7 July 2010 a $35,212,375 firm-fixed-price contract. This contract was to purchase 6,180 M2E2 quick change barrel kits, providing warfighters with a faster, more accurate way to change barrels on the M2 machine gun and decreasing exposure to enemy fire. It was deemed critical that the warfighter have the capability to quickly change the barrel and resume firing without resetting the headspace and timing, and to maneuver with the weapons in a ready-to-fire fashion. Work was to be performed in Saco, Maine with an estimated completion date of 23 December 2012. Three bids were solicited with 3 bids received. Army Contracting Command, Joint Munitions and Lethality Life Cycle Management Command at Picatinny Arsenal, New Jersey was the contracting activity.
On 24 September 2010, General Dynamics Armament and Technical Products announced that the US Army Joint Munitions and Lethality Life Cycle Management Command at Picatinny, New Jersey had awarded it an order valued at approximately $35 million to manufacture M2A1 quick change barrel conversion kits. The quick change conversion kits featured several direct-replacement parts to modify existing M2 heavy barrel machine guns to the M2A1 configuration. Deliveries were scheduled to begin in January 2011 and would continue through December 2012.
On 15 October 2010, PEO Soldier's Brigadier General Peter N. Fuller type classified as standard the new .50 Caliber M2A1 machine gun, marking a new chapter in the life of the Army's "Ma Deuce." By spring 2011, all new M2s coming off the assembly lines would be manufactured to M2A1 specifications, a significant upgrade that enables Warfighters to deliver increased volumes of fire at the enemy while enhancing Soldier safety in the operation of the system.
The upgrade was made possible by a host of organizations across the Army, from Project Manager Soldier Weapons and Army Armament Research, Development and Engineering Center (ARDEC), to Tank-Automotive and Armaments Command (TACOM) and contracting centers at Warren and Picatinny. After the first unit was equipped with new M2A1s in summer 2011, M2s in the field would begin to be returned to Anniston Army Depot for refitting with the Quick Change Barrel (QCB) Kit, bringing the M2s up to the new M2A1 standard. Units would receive M2A1s in a one-for-one exchange for their M2s.
Once new production and M2A1 conversion programs were fully under way, more than 750 guns would become available to Army units each month, enough to outfit more than a dozen brigade combat teams in just 6 months. Fielding priority would go to deployers and redeployers. In time, the Army's entire fleet of more than 45,000 M2s were to receive the upgrade.
On 10 December 2010, General Dynamics Armament and Technical Products announced that it had been awarded 2 delivery orders and a contract modification in August 2010 by the US Army TACOM Life Cycle Management Command to produce 5,080 M2 heavy barrel machine guns and to convert an additional 6,000 M2HB guns to the M2A1 configuration. The cumulative value of the awards was $73.5 million.
Join the GlobalSecurity.org mailing list