The US Military’s Workhorse GPMG: The M240! By: Jim Davis


Have you wondered about what the main General Purpose Machine Gun is for the US Military? It used to be the M60, but that GPMG has been surpassed by a different model, the M240. The M240 is well-liked among the troops for its reliability; and indeed, it is perhaps the most reliable GPMG in use today, given its low failure rate. In the military, it is used far and wide, being mounted on nearly every vehicle and many aircraft, in addition to the infantry role. Let’s take a closer look at the M240.

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Originally called the MAG 58, the US Military adopted the weapon in 1977 and designated it the M240. Since then, it has also been adopted by the US Marines, Navy, and Coast Guard. The Marines designated it the M240G, while the Army has the M240B. There are some subtle differences, but overall, they are basically the same weapon. Although the M240 has officially replaced the M60, the M60 can still be found in the military inventory (they don’t tend to throw things away).

The FN MAG 58’s receiver has many similarities with the Browning Automatic Rifle. The receiver was inverted from that of the BAR so that it could accept a belt feed, rather than magazines from the bottom. As such, the MAG 58/M240 has a long lineage dating back to WWI, as John Browning designed the BAR way back then.

Browning Automatic Rifle.
Amazingly, the M240’s lineage dates all the way back to the Browning Automatic Rifle from WWI! The receiver of the M240 was based on the old Browning design. (Photo: American Rifleman)

The US Marines adopted the M240G, which has variable rates of fire that can be adjusted via the gas system. The adjustments can be fine-tuned in the event the weapon becomes very dirty. The US Army uses the M240B, which has the standard rate of fire at around 550-650 rounds per minute.

Weighing in at 27.3 pounds, the M240 GPMG is a substantial load to hump on patrol. It fires the 7.62 NATO round with a listed effective range of 800 meters (1,100 when fired from the tripod). The rate of fire is normally 550-650 rounds per minute. However, the M240G can be set to fire at three different rates: 650-750 RPM, 750-850 RPM, and 850-1235 RPM.

A soldier keeps watch on rooftop with M240B.
The M240 was used extensively in Iraq and Afghanistan. This is the M240B being used by the Army. (Photo: Military Leak)

The M240 fires from an open bolt, which means the bolt is held open until the trigger is pulled, at which time the bolt travels forward, stripping a round from the belt and firing the round as it is chambered using a fixed firing pin. The advantage of firing from the open bolt is that, when the chamber is heated from sustained firing, a bullet is not sitting in that hot chamber, which could cause it to fire from the heat (called a “cook-off”).

The method of feeding is from a disintegrating belt (though it can be converted to use non-disintegrating belts) and is gas operated. It accepts belts into the left side of the receiver, and belts normally range from 50 to 250 rounds. The belts come either in boxes or pouches, some of which can be attached directly to the weapon. The belts can be linked together. These days, the infantry normally carries the ammo in cloth pouches, which are more convenient, mobile, and fast to put into use.

Soldier on roof top with M240.
Here we can see the cloth pouch attached to the M240 as this soldier deploys the weapon on a rooftop. (Photo: American Special Ops)

Compared to the M60 GPMG, the M240 is more rugged and reliable, with a Mean Failure Between Stoppage Rate of 26,000 rounds. It has a quick-change barrel so that sustained fire can be utilized, and the carry handle helps in that barrel change. Because the carry handle is attached directly to the barrel, it makes barrel changes fast, and they can be performed without the use of insulated gloves because of that handle.

It can be fired from the shoulder, bipod, tripod, and a plethora of vehicle mounts. It’s commonly mounted on tanks (both on the turret and co-axially), Humvees, armored vehicles of all types, helicopters, and watercraft. The 240 comes standard with a bipod, which is how it is most commonly deployed with the infantry. It truly is a workhorse for our military.

M240 mounted on vehicle.
A favorite of armored vehicles, the M240 is often seen in the mounted role. (Photo: American Special Ops)

Sights on the M240 are leaf-type and marked from 200 to 800 meters. Newer models have an integrated Picatinny rail so that optics can easily be added, which makes the gun even more effective and versatile.


The M240L is a shortened, lightened version of the M240 (it is 5.5 pounds lighter than the standard 240, weighing 22.3 pounds). Titanium is used in some of the construction, which helps to make it lighter. The barrel is also shortened to 21.7 inches (which is four inches shorter than a standard barrel), which not only reduces weight but makes the gun easier to handle, especially in tight confines. The rate of fire remains unchanged from the original version at 550-650 rounds per minute.

Shorter and lighter, the M240L is easier to maneuver, especially in confined spaces, than the full-size M240. (Photo: US DoD)

Who uses the M240?

The Coast Guard arms ships, boats, and helicopters with the M240. Given its versatility and effectiveness, it fills the roles that it is asked to quite well.

Special Warfare Combat Crewmen, who are tasked with inserting, extracting, and working with Navy SEAL Teams, also use the M240 on their watercraft, in addition to several other weapon systems. Aside from special units, the general US Navy also uses the M240 on various watercraft and aircraft.

A number of countries other than the US issue the M240, including Ukraine, Georgia, Indonesia, Philippines, Great Britain, Poland, Argentina, Spain, Australia, Canada, and others. Most recently, the US has used the M240 in the wars in Afghanistan and Iraq, where it served with distinction.

M240 in use by SWCC on boat.
The M240 is a favorite among Special Warfare Combat Crewmen (SWCC), who work closely with the Navy SEALs. Photo:

Not only is it used by the US Military, but also that of many other countries around the globe. At present, it does not appear that there are any plans to replace this design, as it is widely accepted and those who issue it seem pleased with its performance.

M240 with optics.
An optically sighted M240, about to unleash some hell. (Photo: SOFREP)