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The M249 light machine gun (LMG), formerly 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 (it's the US Army's default machine gun). 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 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 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 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. The M249 is sometimes incorrectly referred to as a "Squad Assault Weapon". ==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.〔, A-1 Rifle platoon.〕 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.〔, 7–9 Automatic or burst fire.〕 The 20-round and 30-round magazines of these weapons 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.〔Bonds and Miller 2002, p. 451.〕 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 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.〔, Preface.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「M249 light machine gun」の詳細全文を読む スポンサード リンク
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