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Fabrique Nationale M249 SAW / LMG

Light Machine Gun (LMG) / Squad Support Weapon (SSW) (1984)

Infantry Small Arms / The Warfighter

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Left side view of the M249 SAW; note magazine box and feed as well as bipod and carrying handle
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Top forward right side of the M249 SAW; note carrying handle, muzzle and cocking lever
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An M249 SAW on a post mounting; note bipod, ammunition pack and iron sight
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Close-up detail view of the left side of an M249 SAW; note belt feed mechanism
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A collection of M249 SAWs along a firing range
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A soldier re-loads his M249 SAW; view from the top of the weapon
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Close-up detail view of the business end of an M249 SAW; note scope and wargames attachment
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Right side detail view of an M249 SAW; soldier firing from the shoulder

Jump-to: Specifications

The M-249 is a light machine gun based off of the Belgium Fabrique Nationale FN Minimi system.

Authored By: Staff Writer | Last Edited: 08/15/2021 | Content ©www.MilitaryFactory.com | The following text is exclusive to this site.
When the United States Army moved to adopt a new light machine gun, it selected the excellent Belgian Fabrique Nationale FN Minimi as the "M249 SAW" ("Squad Automatic Weapon"). The M249 became more or less a direct adaptation of the Belgian design with a few Army-requested changes to suit mission needs and American production methodology. The weapon was selected in 1982, introduced with the US Army in 1984 (the US Marines accepted the weapon in 1985) and, after an extensive period of testing common to most US military firearms, the M249 was finally delivered to frontline US Army forces in 1992. By and large, the M249 remains faithful to the overall form and function of the FN Minimi with the most notable change being the addition of a perforated heat shield at the barrel and a new butt. The heat shield protects the operator from accidental burns and also serves to minimize the effects of heat distorting the action as seen through the sights.

Like other modern infantry forces, the US military survives through various levels of specialists that benefit the whole. Base infantryman armed with their standard service rifles head the assault and these forces are supported by specialist troops armed with larger, heavier automatic weapons for suppression fire and direct contact of enemy forces. The M249 fulfills this role as a portable, voluminous fire design intended to support infantry actions at the squad level.

The US move to a more compact machine gun was born from a 1960s initiative which saw American ground forces tied to the cumbersome, rifle-caliber-chambered M60 General Purpose Machine Gun (GPMG) of the Vietnam War era and the Browning M2HB heavy machine gun system. As such, there proved a "bridge requirement" to bring about a more portable system chambered for the smaller 5.56mm NATO round via belt. The weapon would be crewed by a single operator for efficient management in the field and provide the needed sustained fire through a high-volume automatic action. While various experiments were conducted in the Vietnam War to find such a weapon, the solution would not come until well after the war in the 1980s with the settlement of the Belgian FN Minimi. The Minimi was successfully evaluated (as the XM249) beginning in 1974 against the Colt M16 HBAR and the Heckler & Koch HK23A1. Testing continued into 1981.

The M249 retains the general appearance and layout of the FN Minimi before it. The receiver is a large, rectangular block housing the required internal components. The stock is a webbed, twin strutted assembly affixed to the rear of the receiver in the usual way. The trigger group and pistol grip are underslung beneath the receiver. Ahead of the receiver is the forend/handguard shrouding a portion of the barrel and gas cylinder. A folding bipod assembly is fitted at the gas cylinder and collapses rearwards against it when not used. The barrel protrudes a short distance ahead of the forend and is capped by a conical slotted flash hider. Iron sights are provided over the receiver and midway along the barrel. A carrying handle is offset to the right side to facilitate transport and barrel changing. Ammunition is fed through a port along the left side (box or belt) and exits from the right. Sling loops allow use of a shoulder strap. The M249 can also be supported via the M192 LGM tripod assembly.
The M249 features a running length of 41 inches with an unloaded weight of 16lbs. The barrel measures 18 to 20.5 inches long and is rifled with 6-grooves and a right-hand twist. The weapon is chambered for the 5.56x45mm NATO standard cartridge - the same as used in the M16 series of assault rifles and M4 Carbines - and can fire from a 30-round detachable box hard magazine (STANAG) or a 200-round M27 series metal linked belt in a soft case. The M249 can, therefore, actually be fed by way of the M16/M4 magazine. Cyclic rate-of-fire is 750 rounds per minute with a muzzle velocity of 3,000 feet per second at effective ranges out to 870 yards and a maximum range out to 3,900 yards. The firing action is of gas-operation through an open bolt arrangement. A typical SAW man is afforded 2 x 200-round 5.56mm belts.

The M249 received its baptism of fire in the 1989 US invasion of Panama to unseat dictator Manuel Noriega. It then was pressed into action once more in larger numbers during the 1991 Gulf War. From then on, the weapon has seen consistent service through the Bosnian and Kosovo wars, the 2001 US-led invasion of Afghanistan and the 2003 US-led invasion of Iraq. In service, the M249 has given good results as a reliable, high-volume fire weapon. It excelled when used as a stationary weapon though with slightly poorer results when operated from the shoulder. In particular, the M249 proved prone to capturing dirt and sand and this went on to become the weapon's major complaint by users. A collapsible butt was eventually issued for a more compact profile and recognized as the "Para" version for its airborne paratrooper intention. The M249 has become a stable of American urban warfare engagements in Iraq.

Production of American M249s is handled by FN Manufacturing Company of Columbia, South Carolina, USA. The initial batch of 1,100 M249s were built and delivered directly from Belgian factories and were marked as such. Since entering service as the "M249 SAW", the system has been redesignated in 1994 to "M249 Light Machine Gun (LMG)".

The M249 has been manufactured or modified into several notable forms beyond the first generation base M249. The M249 PIP was an early Product Improvement Program form with a plastic stock replacing the original metal one. New sights were also added as was a new pistol grip, bipod and flash suppressor. Picatinny rail sections were eventually installed. The M249 PARA is a more compact version with sliding butt. The M249 Special Purpose Weapon is a compact SOCOM series version with weight reduction taken to the extreme - lacking the carrying handle, magazine well and vehicle mounting hardware. Another SOCOM type is the Mk 46 Mod 0 with Picatinny rail support and varying barrel options. The Mk 48 is yet another SOCOM breed following the Mk 46 Mod 0 though chambered for the larger rifle-caliber 7.62x51mm NATO standard cartridge.

It is noteworthy that the FN Minimi has been adopted by many major modern world forces including Australia, Brazil, Canada, France, Indonesia, Italy, Japan, Malaysia, Mexico, Pakistan, Philippines, Poland, Spain, Sweden, Taiwan, Thailand, Turkey and the United Kingdom (among others).


Service Year

United States national flag graphic
United States


Light Machine Gun (LMG) / Squad Support Weapon (SSW)

FN Manufacturing, Incorporated - USA
National flag of Afghanistan National flag of Australia National flag of Belgium National flag of Brazil National flag of Canada National flag of Chile National flag of Croatia National flag of Czechia National flag of Denmark National flag of the Dominican Republic National flag of Egypt National flag of France National flag of Greece National flag of Hungary National flag of India National flag of Indonesia National flag of Iraq National flag of Ireland National flag of Italy National flag of modern Japan National flag of Jordan National flag of Lebanon National flag of Malaysia National flag of Mexico National flag of Morocco National flag of the Netherlands National flag of New Zealand National flag of Norway National flag of Pakistan National flag of Peru National flag of the Philippines National flag of Poland National flag of Serbia National flag of Slovakia National flag of Slovenia National flag of Spain National flag of Sri Lanka National flag of Sweden National flag of Switzerland National flag of Taiwan National flag of Thailand National flag of Turkey National flag of the United Arab Emirates National flag of the United Kingdom National flag of the United States National flag of Vietnam Afghanistan; Australia; Belgium; Brazil; Canada; Chile; Croatia; Czech Republic; Denmark; Dominican Republic; East Timor; Egypt; El Salvador; France; Greece; Hungary; Indonesia; Iraq; Ireland; India; Italy; Japan; Jordan; Latvia; Lebanon; Luxembourg; Malaysia; Mexico; Morocco; Nepal; Netherlands; New Zealand; Norway; Pakistan; Papua New Guinea; Peru; Philippines; Poland; Serbia; Slovakia; Slovenia; Spain; Sri Lanka; Suriname; Sweden; Switzerland; Taiwan; Thailand; Turkey; United Arab Emirates; United Kingdom; United States; Vietnam
(OPERATORS list includes past, present, and future operators when applicable)
Fire Support
Capable of suppressing enemy elements at range through direct or in-direct fire.
Special Forces
Qualities of this weapon have shown its value to Special Forces elements requiring a versatile, reliable solution for the rigors of special assignments.

Overall Length
1,035 mm
40.75 in
Barrel Length
465 mm
18.31 in
Empty Wgt
16.53 lb
7.50 kg

Iron Front and Rear; Optional Optics


Gas-Operated; Open Bolt

Open Bolt
System utilizes internal mechanism where bolt and associated working components are set to the rear of the receiver with no cartridge chambered; trigger actuation moves bolt forward, chambers cartridge, and fires bullet in single action - ultimately resetting during the complete cycle by way of the generated energy.
Gas-operated system is featured, typically involving a gas cylinder and rear-driven piston directing energy to the bolt component.
(Material presented above is for historical and entertainment value and should not be construed as usable for hardware restoration, maintenance, or general operation - always consult official manufacturer sources for such information)


5.56x45mm NATO; 7.62x51mm NATO

Sample Visuals**

Graphical image of a 5.56mm intermediate rifle cartridge
Graphical image of a 7.62x51mm / .308 Winchester rifle cartridge
Rounds / Feed

30-round detachable box; 200-round metal link belt
Cartridge relative size chart
*May not represent an exhuastive list; calibers are model-specific dependent, always consult official manufacturer sources.
**Graphics not to actual size; not all cartridges may be represented visually; graphics intended for general reference only.
Max Eff.Range
2,600 ft
(792 m | 867 yd)
Muzzle Velocity
3,000 ft/sec
(914 m/sec)

M249 - Base Series Designation; based on the Belgian FN Minimi light machine gun.
M249 PIP ("Product Improvement Program") - Improved M249 models with plastic stock, folding carrying handle, barrel handguard, revised bipod, revised flash hider, revised pistol grip and new sighting installations.
M249 PARA - Compact variant intended for paratroopers; shorter barrel and gas cylinder with collapsible butt.
M249 SPW ("Special Purpose Weapon") - US SOCOM variant sans magazine well, vehicle mounting hardware and carrying handle.
Mk 46 Mod 0 - Lightweight US SOCOM variant with Picatinny rail support.
Mk 48 - US SOCOM variant following Mk 46 Mod 0 though chambered for the 7.62x51mm NATO standard cartridge.

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