|Light Machine Gun, 5.56 mm, M249|
|Type||Squad automatic weapon/Light machine gun|
|Place of origin|| Belgium
|Used by||United States Armed Forces, Lebanon, Italy|
|Wars||Invasion of Panama
Unified Task Force
|Manufacturer||Fabrique Nationale de Herstal|
|Unit cost||US$4,087[3 ]|
|Weight||7.5 kg (17 lb) empty,
10 kg (22 lb) loaded
|Length||1,041 mm (41 in)|
|Barrel length||521 mm (21 in)|
|Cartridge||5.56x45 mm NATO|
|Action||Gas-operated, open bolt|
|Rate of fire||750–1,000 rounds per minute|
|Muzzle velocity||915 m/s (3,000 ft/s)|
|Effective range||1,000 m (1,090 yd)|
|Feed system||M27 linked belt, STANAG magazine|
The M249 light machine gun (LMG), previously designated the M249 Squad Automatic Weapon (SAW), and formally written as Light Machine Gun, 5.56 mm, M249, is an American version of the FN Minimi, a light machine gun manufactured by the Belgian company FN Herstal (FN). The M249 is manufactured in the United States and is widely used by the U.S. Armed Forces. The gun was introduced in 1984 after being judged the most effective of a number of candidate weapons to address the lack of automatic firepower in small units. The gun provides infantry squads with the heavy volume of fire of a machine gun combined with accuracy and portability approaching that of a rifle.
The M249 is gas-operated and air-cooled. It has a quick-change barrel, allowing the gunner to rapidly replace an overheated or jammed barrel. A folding bipod is attached near the front of the gun, though an M192 LGM tripod is also available. It can be fed from both linked ammunition and STANAG magazines, like those used in the M16 and M4. This allows the SAW gunner to use rifleman's magazines as an emergency source of ammunition in the event that he runs out of linked rounds. However, this will often cause malfunctions because the magazine spring has difficulty feeding rounds quickly enough to match the SAW's high cyclic rate.
M249s have seen action in every major conflict involving the United States since the 1989 invasion of Panama. Soldiers are generally satisfied with the weapon's performance, though there have been reports of clogging with dirt and sand. Due to the weight and age of the weapon, the U.S. Marine Corps (USMC) is considering designs for an infantry automatic rifle, which is planned to complement and partially replace the M249 in their service.
In 1965, the U.S. Army and Marine Corps' primary machine guns were the M2 Browning and M60. The M2 was a large-caliber heavy machine gun, usually mounted on vehicles or in fixed emplacements. The M60 was a more mobile medium machine gun intended to be carried with the troops to provide heavy automatic fire. Both were very heavy weapons and usually required a crew of at least two to operate efficiently. The Browning automatic rifle, the army's main individual machine gun since its introduction in World War I, was phased out in 1957 with the introduction of the M14 rifle, which had a fully automatic mode. "Designated riflemen" in every squad were ordered to use their weapons on the fully automatic setting, while other troops were required to use their rifle's semi-automatic mode on most occasions to increase accuracy and conserve ammunition. Because the M14 and M16 rifles had not been designed with sustained automatic fire in mind, they often overheated or jammed. The 30-round magazines of these weapons also limited their sustained automatic effectiveness when compared to belt-fed weapons.
The Army decided that an individual machine gun, lighter than the M60, but with more firepower than the M16, would be advantageous; troops would no longer have to rely on rifles for automatic fire. Through the 1960s, the introduction of a machine gun into the infantry squad was examined in various studies. While there was a brief flirtation with the concept of a flechette- or dart-firing Universal Machine Gun during one study, most light machine gun experiments concentrated on the Stoner 63 light machine gun, a modular weapon which could be easily modified for different purposes. The Stoner 63 LMG saw combat for a brief period in Vietnam with the USMC, and later on a wider scale with the U.S. Navy SEALs.
In 1968, the Army Small Arms Program developed plans for a new 5.56 mm caliber LMG, though no funds were allocated (5.56 mm ammunition was viewed as underpowered by many in the armed forces). Studies of improved 5.56 mm ammunition, with better performance characteristics, began. The earliest reference to studies of other caliber cartridges for the LMG did not appear until 1969. In July 1970, the U.S. Army finally approved development of an LMG, with no specified calibre. At this time, the nomenclature "Squad Automatic Weapon" (SAW) was introduced. Actual design of alternative cartridges for the LMG did not begin until July 1971. A month later, Frankford Arsenal decided upon two cartridge designs for the new LMG: a 6 mm cartridge and a new 5.56 mm cartridge with a much larger case.[15 ] Neither design was finalized by March 1972, when the Army published the specifications document for the planned SAW. The 6 mm cartridge design was eventually approved in May that year. Prior to July 1972, SAW development contracts were awarded to Maremont, Philco Ford, and the Rodman Laboratory at Rock Island Arsenal. These companies produced designs with Army designations XM233, XM234 and XM235 respectively—X denoting "experimental". Designs were required to have a weight of less than 9.07 kg (20 lb) including 200 rounds of ammunition, and a range of at least 800 meters (2,600 ft). 
When the time came for developmental and operational testing of the SAW candidates, three 5.56 mm candidate weapons were included with the 6 mm candidates: the M16 HBAR, a heavy-barrel variant of the M16 designed for prolonged firing; the Fabrique Nationale de Herstal (FN) Minimi; and the HK 23A1. The initial round of tests ended in December 1974. In February 1976, the Minimi and Rodman XM235 SAW were selected for further development. At this time, opinions of the 6 mm cartridge were beginning to sour due to the logistical implications of providing yet another ammunition type to the infantry. In June, it was requested that the SAW specifications document be revised to emphasize standard 5.56 mm ammunition. In October, the requested revisions were approved, and bids were solicited for the conversion of the Rodman XM235 to 5.56 mm. Production of the converted XM235 was awarded to Ford Aerospace, and its designation was changed to XM248. A new M16 HBAR variant, the XM106, was developed in 1978, and soon after, Heckler & Koch lobbied to include a 5.56 mm conversion of its HK 21A1 (instead of the standard 7.62 mm NATO ammunition it was built for) in future SAW testing. The latter model was designated the XM262. At this time, the 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 the grounds of performance and cost, while the HK XM262 reportedly came a close second.  In September, FN was awarded a "maturity phase" contract for further development of the XM249, and testing of the new weapon began in June 1981.  The official adoption took place on February 1, 1982.
The new gun entered U.S. Army service as the M249 squad automatic weapon in 1984, and was adopted by the U.S. Marine Corps a year later. The U.S. production model has a different butt from that of the regular Minimi.  It is manufactured in the FN factory in Columbia, South Carolina.
Although found to be reliable and accurate, the M249 was considered to present unacceptable hazards in the form of an exposed hot barrel and sharp edges. There were also complaints that the front sight required special adjustment tools. On August 23, 1985, Undersecretary of the U.S. Army James R. Ambrose suspended M249 production pending the development of the product improvement program (PIP) intended to fix these problems. Congress deleted funds for the M249 from the Fiscal Year 1986 defense budget, then retroactively set aside the program's prior year's funds from the M249 program for other purposes, including retirement and pay raises. Over 1,100 M249s already issued were to remain in use, but be retrofitted with the PIP kit when it became available. Over 7,000 remaining M249s were to stay in storage at depots until corrective changes could be made. The PIP kit was eventually developed and implemented, and production of the M249 resumed.  In 1994 the M249 squad automatic weapon was re-designated the M249 light machine gun.
The M249 is a belt-fed light machine gun. It fires the 5.56x45 mm NATO cartridge, usually a combination of one M856 tracer and four M855 ball cartridges fed from M27 linked belts. Belts are typically held in a hard plastic or soft canvas box attached to the underside of the weapon.
It fires from an open bolt and is gas operated. When the trigger is pulled, the bolt and bolt carrier move forward under the power of the recoil spring. A cartridge is stripped from the belt, chambered, and discharged, sending a bullet down the bore. Expanding propellant gases are diverted through a hole in the barrel into a chamber. This pressure moves a piston providing the energy to extract and eject the spent casing as well as advance the belt and compress the recoil spring, thus preparing for subsequent shots. At 1,041 mm (41 in) long and 7.5 kg (17 lb) in weight (10 kg (22 lb) including a 200-round belt and plastic ammo box), the M249 is a cumbersome weapon.
The barrel has a rifling twist rate of one turn in 180 mm (7 in). Because firing heats up the bore, the air-cooled barrel is equipped with a mechanism to remove and replace the barrel assembly with a spare. A folding bipod with adjustable legs is attached near the front of the weapon, though there are provisions for hard-mounting to a M192 Lightweight Ground Mount tripod or vehicle mount. The M249 provides accuracy approaching that of a rifle, combined with the sustained volume of fire of a machine gun. Its original gas regulator offered two different gas port sizes, allowing cyclic rates of fire of 750 rounds per minute (r/min) or 1,000 r/min. The latter setting was intended for adverse conditions such as an excessively dirty firearm or cold weather. The two-position gas regulator was discarded as part of a product improvement program. Sustained rate of fire, the rate of fire at which the gunner can fire continuously without overheating, is approximately 85 r/min.
Retired U.S. LMG
U.S. Service Rifle
|Weight loaded||9.5 kg (21 lb)||10 kg (22 lb)||9.1 kg (20 lb)||4 kg (9 lb)||15.8 kg (35 lb)||5.56 kg (12 lb)||9.7 kg (21 lb)||6.8 kg (15 lb)|
|Length||1,194 mm (47 in)||1,041 mm (41 in)||893 mm (35 in)||1,000 mm (39 in)||1,245 mm (49 in)||1,060 mm (42 in)||1,020 mm (40 in)||1,030 mm (41 in)|
|Cartridge||30-06 Springfield||5.56x45mm NATO||5.56x45 mm NATO||5.56x45 mm NATO||7.62x51 mm NATO||5.45x39 mm||5.56x45 mm NATO||5.56x45 mm NATO|
|Ammunition feed||20-round box mag||200-round belt||200-round belt||30-round box mag||200-round belt||45-round box mag||150-round belt||100-round drum|
|Muzzle velocity||860 m/s (2,820 ft/s)||915 m/s (3,000 ft/s)||915 m/s (3,000 ft/s)||930 m/s (3,050 ft/s)||905 m/s (2,970 ft/s)||960 m/s (3,150 ft/s)||915 m/s (3,000 ft/s)||970 m/s (3,180 ft/s)|
The M249 LMG entered service in 1984 as the M249 SAW. Initial reactions to the gun were mixed: it fulfilled the light machine gun role well when fired from the ground, but was not as effective when fired from the shoulder or hip. It was praised for its extreme durability and massive firepower, though a number of areas for improvement were highlighted: the blank firing attachment fitted poorly, the bipod was very weak and broke easily, the sling attachment was awkward, and there were many slots and gaps which accumulated dirt. Some claimed that the heavy-barrelled version of the M16 rifle was a more effective light machine gun.
The M249 SAW was not used heavily before the 1991 Gulf War, though it 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 weapons were donated to Bolivia, Colombia and Tunisia.
Tactically, 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 usual load of ammunition carried by gunners is 1,000 rounds in 5 200-round belts, although up to 500 extra rounds generally get loaded into 100 round soft boxes called nut sacks.[3 ]
929 M249 SAWs were issued to personnel from the U.S. Army and USMC during the 1991 Gulf War, though the older M60 machine gun was still more common. Although exposure to combat was scarce, M249 gunners who were involved in fighting mainly used their weapons to provide cover fire for friendly maneuvering troops from fixed positions, rather than maneuvering with them.  There were many complaints about the weapons clogging up with sand after prolonged use in the desert environment.
The standard squad automatic weapon in Afghanistan is the M249 with PIP kit, which serves alongside its heavier counterpart, the M240 machine gun. Almost every eight-man squad deployed is issued two M249s. Most M249s were given a collapsible buttstock immediately prior to the invasion to reduce length and make the weapons more practical for parachuting and close-quarters combat.[33 ] Special forces soldiers typically favor the shorter Para version of the weapon, which weighs much less.[3 ]
A report entitled Lessons Learned in Afghanistan was released by Lieutenant Colonel Charlie Dean and Sergeant Sam Newland of the U.S. Army Natick Soldier Center in 2002. They found that 54% of SAW gunners had problems maintaining their weapons, and 30% reported the gun rusted easily. Soldiers reported ammunition boxes rattling and falling off. 80% percent of soldiers surveyed were pleased with the weapon's accuracy and lethality, and only 64% were confident in their weapon. Weapons clogging up with sand in the desert seems to be the main complaint.
The PIP and Para versions of the M249 have also been used in the Iraq war since the invasion. By 2004, many M249s had been in service for almost twenty years and were becoming increasingly unreliable. Soldiers were requesting replacements and new features, and there are reports of soldiers holding their weapons together with duct tape. The lethality of the 5.56 mm ammunition has been called into question by reports of enemy soldiers still firing after being hit multiple times. As in previous conflicts, the sandy environment causes the M249s and other weapons to clog up and jam if they are not cleaned very regularly.
Operation Iraqi Freedom PEO Soldier Lessons Learned, a report on the performance of weapons in Iraq, was published by Lieutenant Colonel Jim Smith of the U.S. Army on May 15 2003. Smith spoke positively of the M249, claiming that it "provided the requisite firepower at the squad level as intended". He praised the SPW variant, noting that its "short barrel and forward pistol grip allowed for very effective use of the SAW in urban terrain". At the National Defense Industrial Association in 2007, Colonel Al Kelly of the 1st Battalion, 17th Infantry gave a presentation describing the M249 as having "good range, excellent reliability" and an "excellent tracer". He said that a cloth pouch was preferred over the plastic box for holding linked ammunition, and that "knock-down power is poor but is compensated by rate of fire".
Many of the M249s in U.S. Army and Marine Corps service have been worn down by continuous use and are becoming increasingly unreliable. A refurbishment program intended to extend the service lives of these M249s has been carried out, though the weapons are still deteriorating from heavy use. In particular, warping of the receiver rails is a nearly ubiquitous defect in heavily used first-generation M249s. This defect is no longer present on the current-issue M249, which has reinforced rails and full-length welding rather than spot welding. The Marine Corps is looking for a lighter rifle to supplement and partially replace the M249 and has accepted test submissions for this Infantry Automatic Rifle (IAR) concept. The Marine Corps plans to buy up to 4,100 IARs to complement and partially replace its 10,000 M249s, of which 8,000 will remain in service for when more firepower is required.
The U.S. Army does not plan to introduce the IAR. Colonel Robert Radcliffe of the U.S. Army Infantry Research and Development Center stated that an automatic rifle with a magazine would lower the effectiveness and firepower of a squad. While the Marine Corps has 13-man squads, the Army organizes its soldiers into squads of nine and needs considerably more firepower from the squad machine gunners to make up the difference. The U.S. Army does, however, want to replace aging M249s with newer SAWs.
The U.S. Army is currently working on replacing the M249's buttstock with a redesigned adjustable stock.