M249 SAW: The World's Most Popular Squad Automatic Weapon

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Used by members of NATO as well as many other countries, since it began production in 1977, the FN Minimi has been adopted by more than 75 countries. In the USA, it is known as the M249, in Canada as the C9, in the UK as the L108A1, in Australia as the F89, in Sweden as the Ksp 90, in Switzerland as the Lmg 05, but no matter what the designation, it remains the same excellent LMG (Light Machine Gun) or SAW (Squad Automatic Weapon).

The Minimi fires from an open rotary bolt and uses a gas-operated, long-stroke piston operating system. It is air-cooled and may be fed from a magazine or belt. Standard NATO STANAG M16 magazines may be used in the M249. A clever feature was that when a belt was in place, the magazine port was blocked and when a magazine was in place the beltway was blocked. Belts are 200-round disintegrating type. An adjustable gas valve allows adjustment for adverse conditions and/or fouling.

The Minimi’s receiver is fabricated of stamped steel. Barrels are chrome lined and have been available with either 1:7 or 1:12 twist, though with wide adoption of the SS109 load, the 1:7 barrels are more widely used. A quick-change lever on the left side of the Minimi unlocks the barrel allowing a well-trained soldier to change it in less than 10 seconds. A folding bipod is affixed to the gas tube. The primary manufacturer is FN Herstal, but M249s are manufactured at FN Manufacturing LLC in the USA. Many other countries also manufacture Minimis for their armed forces.

When development began on the weapon that would become the Minimi, the FN MAG, a 7.62x51MM GPMG (General Purpose Machine Gun), was already widely used. As a result, a LMG design from FN would automatically create interest. The USA, having adopted the 5.56x45mm M16, was searching for a LMG (Light Machine Gun) in the same caliber, while continuing to use the M60 GPMG. The US DOD had issued bid specs for a new SAW (Squad Automatic Weapon) in 1972. While developing the Minimi, FN was well aware of the interest of the USA in such a weapon, and the importance of US adoption of the weapon to engender major sales.

During initial development, the Minimi resembled a scaled-down FN MAG. US doctrine that had evolved to specify two SAW gunners to each squad would influence FN’s quest for a Minimi that would sell to the US armed forces. Also pushing FN on development of the Minimi was the presence of three competing designs from US manufacturers: Philco (XM233), Ford (XM234), and Rodman Laboratories (XM235).

Throughout the development stages, the Minimi evolved into the weapon that is so ubiquitous today. The Minimi in almost its final form was tested in April 1979, against various other designs. For purposes of the tests, the Minimi was designated the XM249, a designation it would keep, minus the “X,” after being adopted. Over almost a year of testing, the potential SAWs were evaluated on 54 criteria, with the Minimi meeting more than any other competitor. The Minimi was adopted as the M249 with an initial order for 68,000 machine guns, the first 2,000 to be produced in Belgium and the remainder in an FN plant in the USA.

One of the great selling points for the Minimi is its versatility that has allowed it to be adopted for various missions. For example, the Minimi Para Model was developed in the 1990s to make the weapon more portable. Features include a shorter barrel and retractable folding stock. Later models incorporate a Picatinny Rail for mounting optical sights.

The Minimi Para TR has a triple Picatinny Rail allowing mounting of a vertical fore grip and/or illuminators and pointers. The US M249 Para has a different type of heat shield over the quick-change barrel and a retractable five-position stock similar to that of the M4 Carbine. This stock is also more soldier-friendly for troops wearing body armor. The Minimi Mk 3 Para Model has a shorter plastic forearm with short Picatinny rails. Other upgrades include a more ergonomic cocking handle and an improved feed tray.

Although many of the countries which are using the Minimi also use the FN MAG GPMG, the USA and some other countries expressed interest in a scaled-up Minimi to fire the 7.62x51mm round. For US SOCOM (Special Operations Command), the Mk. 48 Mod 0 was developed as an “M249” firing the 7.62x51mm cartridge at a lower cyclic rate. The US Navy SEALs and US Army Rangers have used this variant.

Military M249 gunners are trained that “sustained rate of fire” intended to suppress enemy fire is 100 RPM, which does not overheat the barrel. “Rapid Fire” is 200 RPM, which is used on the defense to break an assault. As 200 linked rounds is the standard load for a soft or hard ammo container, this rate would be easy to monitor. Gunners are admonished that firing at a faster rate will quickly overheat the barrel.

The M249 Capabilities

• Max. Range: 3,600 meters
• Point Target: 800 meters
• Area Target: 1,000 meters
• Grazing Fire: 600 meters
• Tracer Burnout: 900 meters

Tactical missions for the Squad Automatic Rifleman in the US Army illustrate the need for the M249 to be mobile. Among these missions are: target suppression, overwatch, building clearing, cave/tunnel/dugout clearing, backing up security checkpoints, and myriad other scenarios where immediate engagement with a lot of rounds down range is needed.

The Minimi or M249 is often mounted on a variety of vehicles from Humvees to various light armored vehicles. In addition to typical pintle or pedestal mounts, more sophisticated RWS (Remote Weapons System) mounts that allow the soldier to operate the weapon while remaining under armored cover in the vehicle are in use. Equipped with night sights, laser range finders, high-capacity ammo boxes, stabilizer for firing while the vehicle is moving, target tracking systems, and various other high tech devices, an M249 may be fired via a remote cable while its operator remains within the vehicle.

In the past, I’ve fired both Minimis and M249s, standard and Para models. For this article, I fired a standard FN-manufactured Minimi. Various features affecting operation of the Minimi or M249 may have been mentioned in passing already, but I want to point some of them out again. The Minimi is full-auto only so there is no selector switch. Instead, there is a cross bolt safety above the pistol grip. On the right side just behind the forearm is the cocking handle.

Speaking of the forearm, though it does not extend a great distance, it is invaluable when firing the Minimi offhand. Although I had no need of using it, the gas regulator collar is located at the front of the receiver where it is easily reached. The skeleton stock on the weapon I fired was the early skeleton type with the flip-up shoulder rest. Useful if moving quickly with the Minimi, the carry/barrel change handle can be folded down when firing.

I have fired an M249 in the past using an M16 30-round magazine, a practice that would normally only be justified if the weapon had gone through all of the available linked ammo. For this test, I fired 200 rounds of linked 5.56x45mm ammo. Before loading, the cocking handle should be pulled to the rear to lock the bolt back; after which, the cocking handle should be pushed to the front. Then, the cross-bolt safety should be applied by pushing it to the right making sure the red line is visible.

The latches for the top cover are located beside the rear sight atop the receiver in back of the cover. After lifting the top cover, any debris should be cleared from the feed tray, then before threading the linked ammo into the feed tray it should be lifted up to be sure the chamber is empty. Normally, it works best to tilt the SAW to the right while using the left hand to pull the first round in the “belt” against the feed tray, then count five or six rounds onto the tray before closing the feed cover, MAKING SURE YOUR HAND IT OUT OF THE WAY. For purposes of photos to show the ammo being fed into the Minimi and the links dropping to the ground, I used the ammo outside of the ammo box, which would normally be used in combat.

As the ground was quite muddy on the day I shot the Minimi, I did not put up targets at 100 and 200 yards. Instead, I aimed at hanging plates and judged accuracy by the sound of hits. I started off firing offhand at 100 yards. The Minimi I was shooting had the standard iron sights, but I found the rear aperture and post usable. I got some hits firing offhand, but I refuse to admit what percentage! Offhand, I was firing five or six round bursts and found the Minimi easily controllable.

To digress a bit, some years ago, I had been asked to evaluate the use of the M249 Para Model to break an ambush of a motorcade. 
In that case, I found the weapon worked well for putting bursts into “attacker” targets at ranges between 25 and 50 yards. By the way, with the Para’s stock collapsed and the 13.7-inch barrel, I found the M249 could be carried in a vehicle, stock resting on the floor between my legs and that the debus drill was fairly quick with some practice.

Back to shooting the Minimi. Firing prone from the bipod in bursts of between five and 10 rounds, hitting the target at 200 yards was fairly easy, though I’ll admit my friend Brian, who was along, hit more consistently. In total, I fired 200 rounds and found the Minimi was reliable, had good ergonomics, and was a pleasure to shoot. I wish we had had an Elcan M145 Machine Optic mounted. In the past, I’ve found I shoot much better with it—Duh!

My conclusion is simple. I understand why so many armies around the world have chosen the Minimi/M249. It’s a really, really good LMG/SAW—really, really! 

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