M249 light machine gun 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 the American adaptation of the Belgian FN Minimi , a light machine gun manufactured by the Belgian company FN Herstal ( FN ) . The M249 is manufactured in the United States by the local subsidiary FN Manufacturing LLC in South Carolina and is widely used in the U . S . Armed Forces . The weapon 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 M249 provides infantry squad s 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 magazine s , 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 where 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 U . S . invasion of Panama in 1989 . 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 United States Marine Corps is fielding the M27 Infantry Automatic Rifle with plans to partially replace the M249 in Marine Corps service . Development . In 1965 , the U . S . Army and U . S . 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 and 20 - 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 caliber . 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 . 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 , then - U . S . Under Secretary of the 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 . Design details . The M249 is a belt - fed light machine gun . It fires the 5 . 56×45 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 long and in weight ( 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 . 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 725 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 . Operational history . 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 for the weapon is 1 , 000 rounds in 5 200 - round belts , although up to 500 extra rounds generally get loaded into 100 round soft boxes . Persian Gulf War . 929 M249 SAWs were issued to personnel from the U . S . Army and USMC during the Persian Gulf War . 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 . Afghanistan . 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 . Special Operations troops typically favor the shorter Para version of the weapon , which weighs much less . A report entitled " Lessons Learned in Afghanistan " was released by Lieutenant Colonel Charlie Dean and SFC 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 , yet only 64 % claimed they were " confident in their weapon " . Weapons clogging up with sand in the desert seems to be the main complaint . Iraq War . 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 the Iraq War , 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 , LTC 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 " . In December 2006 , the Center for Naval Analyses released a report on U . S . small arms in combat . The CNA conducted surveys on 2 , 608 troops returning from combat in Iraq and Afghanistan over the past 12 months . Only troops who fired their weapons at enemy targets were allowed to participate . 341 troops were armed with M249 SAWs , making up 13 percent of the survey . 71 percent of M249 users ( 242 troops ) reported they were satisfied with the weapon . 40 percent of users preferred feeding the SAW with the soft 100 - round pouch , while 21 percent chose the soft and hard 200 - round pouches each . 60 percent ( 205 troops ) were satisfied with handling qualities such as handguards , size , and weight . Of the 40 percent dissatisfied , just under half were with its weight . M249 users had the lowest levels of satisfaction with weapon maintainability at 70 percent ( 239 troops ) , most due to difficulty in removing and receiving small components and poor corrosion resistance . The SAW had the highest levels of stoppages at 30 percent ( 102 troops ) , and 41 percent of those that experienced a stoppage said it had a large impact on their ability to clear the stoppage and re - engage their target . 65 percent ( 222 troops ) did not need their machine guns repaired while in theater . 65 percent ( 222 troops ) were confident in the M249 ' s reliability , defined as level of soldier confidence their weapon will fire without malfunction , and 64 percent ( 218 troops ) were confident in its durability , defined as level of soldier confidence their weapon will not break or need repair . Both factors were attributed to high levels of soldiers performing their own maintenance . 60 percent of M249 users offered recommendations for improvements . 17 percent of requests were for making the weapon lighter , and another 17 percent was for more durable belt links and drums , as well as other modifications such as a collapsible stock . Future . Many of the M249s still in U . S . Army and U . S . 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 U . S . Marine Corps tested the M27 Infantry Automatic Rifle , a lighter , magazine - fed rifle to supplement and partially replace the M249 . With 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 ) held at platoon level , it has acquired 450 of the Heckler & Koch HK416 – based weapons for testing . 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 weapons . They are currently working on replacing the M249 ' s buttstock with a redesigned adjustable stock . The U . S . Army is also looking to replace the M249 with the LSAT light machine gun .