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Meet the M2 Browning: The Machine Gun That Changed Everything

M2 Browning
Soldiers with 1st Battalion, 5th Field Artillery Regiment, 1st Infantry Division fire a .50 caliber machine gun mounted on top of an M109 Paladin in Toruń, Poland, Aug. 26, 2021. The 1-5 is currently deployed to Poland in support of Atlantic Resolve. There are four types of U.S. Army Atlantic Resolve rotations – armored, aviation, sustainment task force and division headquarters. (U.S. Army photo by Spc. Michael Baumberger/RELEASED)

The M2 Browning is one really old machine gun. And yet, this old firearm keeps going to war over and over again – The M2 Browning .50 caliber machine gun is one of the most famous American weapons. Serving since the 1920s, the gun has been a favorite of soldiers in practically every conflict since. It remained the same throughout most of the Cold War, retaining the iron sights, simple pintle mounts, and tripods that were designed for it many decades prior.

But as the United States has stepped up its military commitments around the globe and embarked on a program of modernizing its weapons, the M2 has also had to change. Since 2003 a myriad of improvements have come out for the M2 Browning machine gun to improve its usability, accuracy, and reliability. But even with these upgrades, will they be enough to keep the M2 in service?

M2 Browning Upgrades: 

The biggest upgrade to the M2 Browning was the transition to the M2A1 model in the 2000s. The standard model for most purposes was the M2HB, an air cooled version with a heavy barrel. Changing the barrel on the M2HB was an involved process that required adjusting the “headspace” (the distance between the bolt face and the cartridge) and the timing of the machine gun for every new barrel.

During sustained fire, this was never ideal, as the process would always take a significant amount of time, but changing barrels is a necessity during sustained fire to avoid overheating. The adjustable headspace and timing were necessary at the time, as parts could not be built to the consistent enough tolerances to have a fixed headspace.

However, a few decades later, quick change barrels were becoming the norm. The German MG34 and MG42 that the M2HB faced in World War II both used quick change barrels that could be swapped extremely rapidly. During the Cold War, the Soviets used .50 caliber machine guns (in their own 12.7 x 108 millimeter caliber). The Soviet NSV was lighter than the M2HB, and featured a quick change barrel.

Despite innovation elsewhere, M2HB’s design was not revised to incorporate these new features. The same design, tripods and mounts continued serving up until the 2000s. At that point, the U.S. military held a competition to develop a quick change barrel kit for existing M2s. General Dynamics won the competition for the kit, and it was adopted as the M2A1.

While the primary change was the addition of a quick change barrel kit, the M2A1 also added a four-pronged flash hider to the barrel, reducing the flash of firing, which especially improves the ability to shoot at night with the weapon, as it makes it less prone to washing out NVGs. The barrel extension is also made of a harder steel.

The Army has replaced all of its M2HBs with M2A1s, and the Marines are looking to do the same. A similar setup is being offered as a whole new machine gun as the M2HB QCB by FN Herstal. Some countries have adopted it under that name.

Another upgrade that’s common recently is the attachment of optical sights to the M2 Browning. While Carlos Hathcock famously made an optic mount for a M2HB during his service in Vietnam, optic mounts were not standardized until much later. In comparison, the Soviet NSV came with a standard optic rail, which was commonly used with a 4x to 6x sight.

But nowadays there is a lot of interest for optic mounts for the M2 Browning. The Korean company DI Optical is one of the leaders in this space, producing red dots for the M2HB that have seen use with foreign militaries. Trijicon, who makes the ACOG which has seen wide use also makes a machine gun red dot.

The tripod has also seen improvements. The old M3 tripod of World War II vintage is on the way out in the U.S. Army, being replaced by the new M205 lightweight tripod. The new tripod is sixteen pounds lighter, and has increased traverse and depression range relative to the old tripod.

Charlie Gao studied Political and Computer Science at Grinnell College and is a frequent commentator on defense and national security issues.

Written By

Charlie Gao studied political and computer science at Grinnell College and is a frequent commentator on defense and national security issues.



  1. Lepke Buchalter

    February 26, 2022 at 3:01 pm

    In Vietnam, I changed barrels several times. We carried simple gauges that allowed us to set the head space and timing quickly. But nothing like having a quick change barrel. You usually had to expose yourself to enemy fire to change and set the new barrel.
    In heavy use, like repelling a base overrun, the barrels could glow from red to orange. We had gloves to change hot barrels. Without the gloves, you’d badly burn your hands, like John Basilone on Guadalcanal.

  2. Duke

    February 27, 2022 at 3:18 pm

    The M2 Browning has not been in service since the 20’s, the M2 variant of the .50 cal wasn’t designed until 1933, and even then the original M1921 .50 cal didn’t go into production until 1929, everyone just assumes that because it’s original nomenclature was M1921 that’s when they started production but they didn’t start until 1929.
    There’s major differences between the original M1921 and the M2 including the fact that the original M1921 only fed from the left side, there’s very little parts interchangeability between the two, after the 1933 redesign that produced the M2 it resulted in a weapon that 7 different variants were made from.

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