A member of the 22nd Marine Expeditionary Unit trains with an M27 infantry automatic rifle aboard the amphibious assault ship USS Iwo Jima in the Caribbean Sea, Feb. 4, 2026. (Emily Hazelbaker/U.S. Marine Corps)
The Marine Corps will keep the M27 automatic rifle as its standard service weapon rather than adopt the higher-caliber firearm being fielded by the Army, according to the amphibious force.
“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,” the Corps said in a statement emailed Wednesday by spokesman Lt. Col. Eric Flanagan.
The M27 is a 5.56 mm rifle produced by Heckler & Koch that first saw combat use with Marines in Afghanistan in 2011. The Corps adopted it as the standard service rifle for all infantry battalions in 2018.
The Army, by contrast, is adopting the M7 rifle and M250 machine gun made by SIG Sauer to replace the M4 rifle and M249 machine gun.
The Army M7 production contract gave other customers — the Marine Corps included — an option to adopt the new rifle, Army Col. Scott Madore, project manager for soldier lethality, told reporters in April 2022.
The Marine Corps will monitor the Army’s progress with the M7, according to Flanagan’s email.
The Army’s new weapons fire a 6.8 mm round and are designed to provide increased lethality, longer range and advanced optics that service officials say will reshape small-unit tactics.
Soldiers with the 25th Infantry Division fire M7 rifles during marksmanship training at Schofield Barracks, Hawaii, Jan. 21, 2026. (Timothy Hamlin/U.S. Army)
On Jan. 30, the Army released photos showing members of a marksmanship unit training 25th Infantry Division soldiers in Hawaii on newly fielded M7 rifles.
“We’re not here to reinvent the wheel,” Sgt. 1st Class Alexander Deal, a member of the marksmanship unit, said in a news release accompanying the photos. “The fundamentals of marksmanship don’t change, even when the weapon system does.”
Australia-based defense researcher Allan Orr said the Marines’ decision represents a significant rebuke of the Army’s approach.
The Marines’ most likely adversaries in a future conflict would be Chinese forces operating in dense urban and jungle terrain across Asia, he told Stars and Stripes in an email Wednesday.
In those environments, lessons from the Vietnam War still apply, Orr said, adding that “fire-volume is more important than firepower.”
Maintaining common ammunition with allied forces is also critical, particularly in Southeast Asia, where partners would be needed to offset China’s numerical advantage, Orr wrote.
The issue of diverging cartridge sizes between U.S. services can’t be overstated, he said.
“This announcement (by the Marines) is a massive dis-endorsement of what Army is doing with its small-arms programs and a line drawn now in the Pacific sands,” he said.
