Light Machine Gun

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Lore & Background

The M249 SAW entered U.S. Army service in 1984 and was adopted by the U.S. Marine Corps in 1985. Its development stemmed from a critical gap identified in the 1960s: the M2 Browning and M60 were heavy and required crews, while the BAR had been phased out in 1957. Rifles like the M14 and M16 overheated or jammed under sustained automatic fire. Through the 1960s and 1970s, the Army studied options including the Stoner 63, and by 1970 the 'Squad Automatic Weapon' nomenclature was introduced. After trials of candidates like the Colt M16 HBAR, HK23A1, and FN Minimi, the XM249 was selected in May 1980 for its performance and cost. The weapon was type-classified in February 1982, with full adoption following in 1984 for the Army and 1985 for the Marine Corps. The M249 saw its first combat use during the 1989 invasion of Panama (Operation Just Cause), and has been fielded in every major U.S. conflict since, including the 1991 Gulf War, Somalia in 1993, Bosnia in 1994, Kosovo in 1999, Afghanistan in 2001, and Iraq since 2003.

In Their Own Story

In the desert heat of the Persian Gulf War, a supply of 929 M249 SAWs was issued to U.S. Army and Marine Corps personnel. Gunners who saw combat primarily used the weapon to provide cover fire for maneuvering troops from fixed positions, rather than moving with them. However, the environment took its toll: there were many complaints about the M249 clogging up with sand after prolonged use. Later, in Afghanistan, the standard squad automatic weapon was the M249 with the PIP kit, serving alongside the M240. Most M249s were given a collapsible buttstock prior to the invasion to reduce length for parachuting and close-quarters combat. A 2002 report titled 'Lessons Learned in Afghanistan' by Lieutenant Colonel Charlie Dean and SFC Sam Newland found that 54% of SAW gunners had problems maintaining their M249s, 30% reported the gun rusted easily, and soldiers reported ammunition boxes rattling and falling off. Despite these issues, 80% of soldiers surveyed were pleased with the light machine gun's accuracy.

Reader's Guide

Tactically, M249 SAWs are either carried with a maneuvering unit and fired while handheld, or positioned to remain stationary and provide covering fire for other units. The base load of ammunition was originally 600 rounds, carried in three 200-round boxes. The modern load is 1,000 rounds in five 200-round belts, though up to 500 extra rounds may be loaded into 100-round soft pouches. The weapon features a quick-change barrel, enabling the operator to rapidly replace an overheated or obstructed barrel. It can be paired with a folding bipod attached to the front of the gas block, or attached to an M192 lightweight ground mount tripod. The dual-feeding mechanism allows use of STANAG magazines from the M16 or M4 as a backup. However, initial reactions were mixed: it fulfilled the light machine gun role well from a prone position, but was less effective when fired from the shoulder or hip. It was praised for extreme durability and massive firepower, but criticized for issues like a fragile bipod, awkward sling attachment, and slots that accumulated dirt.

Did You Know?

• The M249 SAW was type-classified in February 1982, but production was suspended on August 23, 1985 by Under Secretary of the Army James R. Ambrose due to safety hazards including sharp edges and an exposed hot barrel.
• The base load of ammunition was originally 600 rounds in three 200-round boxes; the standard combat load is typically 600 rounds, not a fixed 1,000-round base load.
• In a 2002 report titled 'Lessons Learned in Afghanistan', 54% of SAW gunners reported problems maintaining their M249s, and 30% reported the gun rusted easily.
• The M249 SAW was first used in combat during the 1989 invasion of Panama, and has been used in every major U.S. conflict since, including the 1991 Gulf War, Somalia in 1993, Bosnia in 1994, Kosovo in 1999, Afghanistan in
• Surplus M249s were donated to Bolivia, Colombia, and Tunisia.

Origins and Developmental Context

In 1965, the M2 Browning and M60 were the primary machine guns of the U.S. Army and Marine Corps. The M2 was a large-caliber heavy machine gun, usually mounted on vehicles or in fixed emplacements. The M60 was a more mobile general-purpose machine gun intended to be carried by troops. Both were very heavy and usually required a crew of at least two to operate efficiently. The Browning automatic rifle (BAR), the army's main individual machine gun since World War I, was phased out in 1957 with the introduction of the M14 rifle. 'Designated riflemen' in every squad were ordered to use their rifles on fully automatic, while other troops used semi-automatic to conserve ammunition. Because the M14 and M16 were not designed for sustained automatic fire, they often overheated or jammed. The Army decided an individual machine gun, lighter than the M60 but with more firepower than the M16, would be advantageous. Through the 1960s, studies examined the Stoner 63 modular weapon system, which saw brief combat in Vietnam with the Marine Corps and later with the Navy SEALs. In 1968, the Army Small Arms Program developed plans for a new 5.56mm LMG, though no funds were allocated. In July 1970, the Army approved development of an LMG, introducing the 'Squad Automatic Weapon' nomenclature. Actual design for alternative cartridges began in July 1971, with Frankford Arsenal deciding on a 6mm cartridge and a new 5.56mm cartridge with a larger case. The 6mm cartridge design was approved in May 1972. Prior to July 1972, development contracts were awarded to Maremont, Philco Ford, and the Rodman Laboratory, producing the XM233, XM234, and XM235. Designs were required to weigh less than 20 lb including 200 rounds of ammunition, and have a range of at least 800 m.

Competitive Trials and Selection Process

Three 5.56mm candidate light machine guns were included with 6mm candidates in initial trials: the Colt M16 HBAR, the FN Minimi, and the HK23A1. Initial trials ended in December 1974. In February 1976, the Minimi and XM235 were selected for further development. Opinions on the 6mm cartridge were mixed due to logistical implications of multiple calibers. In June 1976, it was requested that the SAW specifications be revised to emphasize standard 5.56mm ammunition. In October, revisions were approved, and bids were solicited for conversion of the Rodman XM235 to 5.56mm. Production of the converted XM235 was awarded to Ford Aerospace, designated XM248. A new M16 HBAR variant, the XM106, was developed in 1978. Heckler & Koch lobbied to include a 5.56mm conversion of its HK21A1, designated the XM262. The FN Minimi received the designation XM249. Testing of the four candidates resumed in April 1979. In May 1980, the FN XM249 was selected as the best choice for future development on grounds of performance and cost, while the HK XM262 reportedly came a close second. In September 1980, FN was awarded a 'maturity phase' contract for further development. Testing of the new light machine gun began in June 1981, and official adoption took place in February 1982.

Technical Design and Operational Features

The M249 SAW is a gas-operated and air-cooled light machine gun. It features a quick-change barrel, enabling the operator to rapidly replace an overheated or obstructed barrel. It can be paired with a folding bipod attached to the front of the gas block, or attached to an M192 lightweight ground mount tripod. The M249 SAW features a dual-feeding mechanism, configured primarily as a belt-fed machine gun while also being compatible with STANAG magazines used in the M16 rifle and M4 carbine. The U.S. production model has a different buttstock compared to the original FN Minimi. Although found to be reliable and accurate, multiple safety hazards were identified, including sharp edges and an exposed hot barrel. Soldiers complained that the front sight required special tools to adjust. On August 23, 1985, Under Secretary of the Army James R. Ambrose suspended M249 production pending a product improvement program (PIP). Congress removed funds from the Fiscal Year 1986 defense budget. Over 1,100 M249s already issued were to remain in use but be retrofitted with the PIP kit. Over 7,000 M249s were to stay in storage at depots until corrective changes could be made. The PIP kit was eventually developed and implemented, and production resumed.

Service History and Modern Replacement

The M249 SAW has been fielded in major conflicts involving the United States military since the United States invasion of Panama in 1989. It was not used consistently before the 1991 Gulf War, but has been used in every major U.S. conflict since. American personnel in Somalia in 1993, Bosnia in 1994, Kosovo in 1999, Afghanistan in 2001, and Iraq since 2003 have been issued M249s. Surplus M249s were donated to Bolivia, Colombia, and Tunisia. In 2009, the United States Marine Corps selected the M27 Infantry Automatic Rifle to partially replace the M249 in USMC service. In 2022, the U.S. Army selected the M250 light machine gun from SIG Sauer to replace the M249 SAW.

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