The Marines may have backtracked on the rifle after a US Army expert disparaged it at an exhibition in Washington, DC, last year.

The United States Marine Corps has increasingly made clear that it isn’t a “Second Army,” and this month also confirmed it won’t adopt the SIG Sauer-designed M7 rifle, opting to retain its M27 Infantry Automatic Rifle. Task and Purpose first reported that the USMC rejected the US Army’s M7, which was selected for the Next Generation Squad Weapons (NGSW) program to replace the M4 carbine and M249 light machine gun.

“The Marine Corps will retain the M27 for our close combat formations as it best aligns with our unique service requirements, amphibious doctrinal employment of weapons, and distinct modernization priorities, while ensuring seamless interoperability across the Joint force and with coalition partners,” a USMC spokesperson told Task & Purpose in an email, but didn’t offer any further information as why the service made the decision.

However, the spokesperson added, “We will continue to monitor development of the M7 [Next Generation Squad Weapon rifle] to inform future requirements.”

Did the Marines Listen to One Soldier?

The US Marine Corps had never officially moved forward with the M7, and in May 2020, the Marine Corps Systems Command even backtracked after it was reported that it would replace the M27 with the NGSW.

Perhaps some Marines listened to what an Army soldier had to say about the M7’s predecessor, the experimental XM7, last year at the Modern Day Marine exhibition in Washington, DC.

Captain Braden Trent, US Army, presented evidence gathered on the XM7 and offered the very blunt conclusion that it is “unfit for use as a modern service rifle.”

Trent added, “The XM7 is a tactically outdated service rifle that would be better classified as a designated marksman rifle, if that.”

As previously reported, the XM7 was based on SIG Sauer’s MCX line, an evolution of the AR-15/M16 rifles used by the military for nearly six decades.

That may have given it a slight advantage over the competing offerings in the NGSW program, with the key differences in the operation. Instead of the direct impingement system found in the AR-15/M16, the MCX utilized a gas piston operating mechanism.

The key benefit was improved reliability, but it comes at a weight trade-off, as the gas piston is heavier. However, the XM7 offered greater range and stopping power, requirements that were borne of experiences in Afghanistan during the Global War on Terror (GWOT). Both the XM7 rifle and XM250 automatic rifle were to be chambered for the newly developed 6.8x51mm Common Cartridge, which was also designated by the Sporting Arms and Ammunition Manufacturers’ Institute (SAAMI) as .277 SIG Fury.

The cartridge was developed to be “midway” between the 5.56x45mm NATO and the 7.62x51mm NATO in bore diameter, even though it is dimensionally similar to the latter round. It should not be confused with the 6.8x43mm Remington cartridge, also developed in recent years.

The Common Cartridge was shown to stop an adversary with a single round, whereas the 5.56 NATO cartridge fired by the M4 required multiple rounds.

In theory, this all sounds good. But Trent based his warnings on how the XM7 has been used in testing, where it hasn’t quite lived up to its promise.

Soldiers complained of the 20-round magazine, which limited the amount of ammunition available in a firefight. In addition, the XM7 is heavier than the M4, and modern tactics still call for engaging a potential adversary at 300 meters or less, negating its longer-range accuracy.

A bigger concern is that the barrel showed excessive wear after just 2,000 rounds.

The M27 Rifle Is the Rifle the Marines Know and Love

The other consideration is that the USMC selected its M27 Infantry Automatic Rifle (IAR), based on the Heckler & Koch, not all that long ago. It was first employed in combat in Afghanistan in 2011, initially to replace the M249, but it has since evolved and replaced the M16A4 and M4A1 as well.

The M27 is still chambered for the 5.56 round, and therefore doesn’t have the stopping power of the XM7’s heavier cartridge, but Marines have touted its greater accuracy and range than the M4. It also employs a short-stroke gas piston system that helps keep the action cleaner and cooler.

An advantage of the 5.56 cartridge is that the Marines can carry more of it, which may be necessary when landing on distant beaches and engaging the enemy at close range. 

About the Author: Peter Suciu

Peter Suciu has contributed over 3,200 published pieces to more than four dozen magazines and websites over a 30-year career in journalism. He regularly writes about military hardware, firearms history, cybersecurity, politics, and international affairs. Peter is also a contributing writer for Forbes and Clearance Jobs. He is based in Michigan. You can follow him on Twitter: @PeterSuciu. You can email the author: Editor@nationalinterest.org.

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