February 4, 2020: U.S. SOCOM (Special Operations Command) recently completed certification of the new Sig Sauer 338 (8.6mm) Machine Gun. This was unusual in many ways. First, the rifle round used here is the 338 Norma Magnum, a round originally designed, about 40 years ago, for big game hunters and then adopted by police and military snipers. Second this 8.6mm machine-gun provides the first real competition for the American M2, .50 (12.7mm) caliber machine-gun. This century old design survived all earlier efforts to come up with an improved design. Long known as “Ma Deuce”, this heavy machine-gun has undergone some upgrades over the years, This made it even more difficult for  new designs could replace it.

The new 8.6mm heavy machine-gun, with a dedicated sound suppressor will, at the very least supplant many existing M2s. This SOCOM certification was followed by an order for an unknown number of these machine-guns but according to request from 2017 SOCOM sought up to 5000 new generation machineguns.

The U.S. Army Special Forces, the largest component of SOCOM, has always sought new equipment and in some cases even co-designed new products. For example, SOCOM was the one reason behind the FN Minimi MK 48 machine-gun. SOCOM began using the Mk 48 7.62mm machine-guns in 2003. These are 8.2 kg (18.3 pound) machine-guns that are lighter than the 10.1 kg (22.2 pound) M-240L or the current standard, 11.8 kg (26 pound), M240B. SOCOM troops needed the light weight for commando operations. But that lightweight comes at the expense of durability. The lighter components don't last as long. For example, the M240 bolt and receiver are both good for 100,000 rounds fired. But on the Mk 48, the bolt has to be replaced after 15,000 rounds and the receiver after 50,000. This was not a problem with the commandos, who made sure they had plenty of spares available and kept track of the (approximate) number of rounds fired. Not so hard to do, you just have to pay attention.

The Mk 48 began as a scaled-up 7.8 kg (17 pound) M249 (the standard 5.56mm) light machine-gun. The Mk 48 only weighs half a kilogram (about a pound) more, and troops always take their M249s with them. Of course, its 7.62mm ammo is heavier. Each 100 rounds of 7.62mm weigh nearly a kilogram (two pounds) more than 100 rounds of 5.56mm. Fortunately, the Mk 48 is usually fired in short, six round, bursts. So a few hundred rounds will last a while.

The search for the Mk 48 started in 2001 when the SOCOM created specs for a new Light Machine Gun (LMG) chambered in 7.62x51 mm NATO. SOCOM wanted something more reliable and lighter than older M60E3. The other available solution the FN MAG (M240) was too heavy. The program result was a success, thus full-rate production of new MG known as MK 48 began in 2003.

The same development process produced the new Sig Sauer 338 machine-gun. The process began in 2017 when the Special Forces and Marines joined forces to find a new lightweight Medium (7.62mm) Machine Gun. The new design should be a 9.1 kilograms (20 pound) weight class at best and able to provide effective fire up to 2,000 meters. Today this type of work, like destroying light fortifications or vehicles, is provided by usual vehicle-mounted M2 heavy (12.7mm) machine guns which have been in wide use since 1933. It is a very potent system but weighs 38.1 kg (84 pounds) for just the weapon and or even more with tripod. The venerable M2 served without many modifications till 2010 when the M2A1 was developed. The M2A1 incorporated a quick change barrel together with a fixed headspace. This was a huge safety upgrade because older M2s had to be manually headspaced after barrel changes which caused many accidents.

It should be noted that the U.S. Army had tried several times to replace the old M2, and all those failed, the two most recent ones in the early 21st century. At the beginning of 2000, there was an ambitious effort that led to the lightweight MG XM312. The program was reorganized in 2008 when the XM312 was cast aside in favor of XM806. Unfortunately, that did not work either and got canceled in 2012. Now the army will have to consider the 8.6mm machine-gun to replace or at least complement M2s.

The Special Forces got tired of waiting and stared their own effort based on their experiences with MK 48. Sig Sauer offered a 10. 9 kg (24 pound) general-purpose machinegun which would usually be mounted on vehicles but was light enough to be used as a light machine-gun (LMG).

The Sig Sauer machine-gun was chambered for the 8.6mm (.338) Norma Magnum ammunition. The 8.6mm round is much more powerful than the standard NATO 7.62x51 round and thus more effective at longer ranges (up to 2,000 meters). However the Sig Sauer designs gun can easily be converted to 7.62x51 if needed.

The Norma Magnum round was introduced in 2009 as an upgrade of the older (1989) Lapua Magnum that was designed for big game hunters and quickly adopted by police snipers. It was a round that can hit effectively out to about 1,600 meters and military snipers soon began to call for its use in their weapons. British snipers in Iraq, and especially Afghanistan, got it early on and found the Lapua Magnum round did the job at twice the range of the standard 7.62x51mm round. The 7.62mm round was developed in the 1950s and based on one developed before World War I. The 8.6mm round entered military use in the early 1990s and became increasingly popular with police and military snipers. British snipers in Afghanistan had many of their 7.62mm sniper rifles converted (by replacing the barrel and receiver) to use the new round. By 2009, the Americans were also on board and a growing number of their sniper rifles got new barrel/receiver assemblies so the Lapua Magnum could be used.

The Norma Magnum was better suited for use in a machine-gun but is otherwise identical in weight and performance to the Lapua Magnum. The new “M338” machine-gun uses a short-stroke gas piston system and a very interesting recoil reduction system with a 605mm (24-inch) free-floating and quick-change barrel. Moreover it has a foldable stock and ambidextrous controls including reversible charging handle together with a feed tray.

SOCOM appears to have once more come up with a breakthrough new weapon. The new design is a basically an M240 weight class with anti-personnel capabilities similar to the M2's. If the SOCOM operators are satisfied, as it appears they are, then the new design has chance to replace famous M2 “Ma Deuce” throughout the U.S. military. While the 8.6mm round does not have the hitting power of the 12.7mm bullet, it has long been accepted that the 12.7mm round was overkill in most cases. The M338 weighs 70 percent less than the M2 and the 8.6mm ammo weight reduction is even greater. More ammo can be carried and getting this ammo to the battlefield is much less of a chore. --- Przemyslaw Juraszek