The Marine Corps is opting to keep the M27 Infantry Automatic Rifle rather than adopt the Army’s higher caliber M7, a service spokesperson confirmed in an email to Military Times.
Lt. Col. Eric Flanagan, a public affairs officer for Marine Corps Combat Development Command, confirmed the decision, stating the M27 is well-suited “for our close combat formations as it best aligns with our unique service requirements, amphibious doctrinal employment of weapons and distinct modernization priorities.”
Flanagan added that the M27 ensures “seamless interoperability across the Joint force and with coalition partners.”
“We will continue to monitor development of the M7 NGSW-R to inform future requirements,” he said.
Task & Purpose was the first to report the service’s decision.
The Marine Corps previously recanted an announcement that it would be replacing the M27 with the Next Generation Squad Weapon, the precursor to the M7, which may have fueled speculation. The Army, meanwhile, recently began fielding the M7 in the 25th Infantry Division in Hawaii.
When comparing the two weapon systems, notable differences emerge in features, operations, weight and cost. However, the most obvious difference between the two is their chambering, which impacts performance and ammunition capacity.
The M27 IAR is chambered for 5.56mm NATO, a legacy cartridge used by the weapon’s predecessors, the M4, M16 and M249 Squad Automatic Weapon. The smaller round also allows the M27 to use the same 30-round magazine as its predecessors.
The M7 rifle is chambered for the larger and more modern 6.8mm cartridge. The higher-pressure round delivers a longer range and greater penetration, but also results in fewer rounds per magazine — 20 instead of 30.
While military weapon enthusiasts may debate the difference between the two systems, both branches have cited reasons for selecting their rifles.
The Marines, for instance, initially selected the M27 to replace the M249 SAW because it delivered automatic fire with greater precision and reliability. The service then opted to make it standard issue in 2018 for all Marines because of its ease-of-use and effectiveness in a wide range of combat scenarios.
The Army, on the other hand, selected the M7 because it delivers greater penetration, including body armor penetration, at longer distances, meaning it delivers greater overall “lethality.”
Unlike the Marines’ one-size-fits-all approach, the Army equips squads with both the M7 rifle and the M250 light machine gun, which can be equipped with a higher capacity magazine.