M2 .50-cal. Machine Gun, Ma Deuce


Weapons enthusiasts have long referred to full-auto fire as “rock and roll,” a term that dates back to the Vietnam War at least. Well, she may be old, but nobody does rock-n-roll like Ma Deuce, the M2 HB (the HB stands for “heavy barrel”) .50-caliber heavy machine gun.

Ma Deuce has been lending a helping hand to the U.S. military since the 1920s. Originally this massive weapon wasn’t really intended for use against personnel; it was mounted by tank commanders’ hatches as an anti-aircraft weapon and on lighter vehicles like cargo trucks and armored cars for anti-vehicle use. A special four-gun anti-aircraft mount was developed during World War II, and most combat aircraft of that war were equipped with it as well.

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Soldiers and Marines, of course, will use whatever they can in combat, so there were plenty of occasions when hordes of massive .50-caliber bullets went blazing downrange toward enemy soldiers. I still remember a crusty Army E-8—Master Sergeant Perez—instructing us with a smug smile around the time of Desert Storm, “the .50-cal isn’t for use against people; it’s for use against equipment—equipment like boots, helmets, rifles, web gear…

The M2 was quite possibly destined for the boneyard eventually until Operation Iraqi Freedom came along. In a combat environment dominated by brick and stone construction, the devastating punch of the .50-caliber round came in quite handy, and combined with the fact that so many gun trucks were mounted with the M2, ammunition supplies began to dry up in 2005. The Army started breaking out stocks manufactured in and just after World War II, and meanwhile moved to ramp up production.

The garden-variety M2HB has a rate of fire between 450 and 600 rounds per minute—very easy to control—and an effective range of 2,000 yards. It is air-cooled and belt-fed, weighing in at 84 pounds (the barrel by itself is 24) excluding any mount.

General Dynamics Armament and Technical Products, which has been manufacturing the M2 for 25 years now, decided to enhance the weapon. It calls the new version the M2E2; the Department of Defense calls it the M2A1. The M2E2 adds a flash hider and a trigger block safety—the original M2 safety can be a bit awkward to use—but most importantly introduces a quick-change barrel. The original M2 requires the gunner to check headspace and timing every time the barrel is changed, and while failure to do so can result in bad things happening (“bad things” ranging from a malfunction to having the weapon blow up in your face), having to check headspace and timing (a process vaguely like gapping a spark plug, but more time-consuming) in the middle of combat isn’t the most practical thing.

Even better things are coming, though. Ma Deuce has a hot young daughter: the XM806, which entered development in 2008. It is designed specifically for use by dismounted ground troops, with 50% less recoil and a total weight with tripod of about 60 pounds. Encouragingly, it look as though the production model—the XM806 enters Phase 2 testing this autumn—is actually going to beat both the weight and recoil reduction requirements.

The ability to deploy the .50-caliber HMG with light infantry units like the 82nd Airborne and 10th Mountain Divisions will be a significant plus to firepower for those soldiers. There is no doubt that Ma Deuce and her descendants will still be in active—and valued—service well past her 100th birthday.