Since the 1970s, Marines have become accustomed to the standard 40mm grenade launcher that can be mounted on the underside of their service rifles. Using the rifle’s 30-round magazine as a pistol grip of sorts, the M203 offered Marines on patrol a similar capability to that of the older M79 grenade launcher. But whereas troops would have to carry the M79 as their primary weapon, the M203 enabled one to carry and quickly utilize both a rifle and a grenade launcher, dramatically expanding the war-fighting capabilities of the user.

Now, for the first time since the 1970s, the Marine Corps is beginning to take delivery of a new under-barrel grenade-launching system: the M320A1 40mm grenade launcher. This new platform, which includes its own pistol grip, can be mounted and fired from beneath a rifle barrel or removed and used as a standalone weapons system. It also offers a number of improvements over its predecessor in design and function.

Capt. Nick Berger, project officer in Infantry Weapons at Marine Corps Systems Command, holds the M320A1 during a weeklong review of the system. In March 2019, MCSC’s Ground Combat Element Systems examined the M320A1 to ensure the operator and maintenance technical publications of the system are accurate. (U.S. Marine Corps photo by Joseph Neigh)

“The M320A1 will provide good range and accuracy, making the infantry squad more lethal,” said Lt. Col. Tim Hough, program manager for infantry weapons in Marine Corps Systems Command’s Ground Combat Element Systems.

At 3.4 pounds, the new M320A1 weighs slightly more than its predecessor, which weighed approximately three pounds, but one can likely attribute the added weight to the weapon’s functionality as a standalone primary weapon when removed from the rifle. In its full standalone weapon configuration, something the M203 could not do, the M320 tops out at about 6.4 pounds.

A U.S. Army paratrooper assigned to the 1st Battalion, 508th Parachute Infantry Regiment fires an M320 Grenade Launcher while conducting a live-fire range January 16 at Camp Atterbury, Indiana. (U.S. Army)

The new grenade launcher offers similar range and accuracy to the older weapon (350-meter max effective range and 150-meter point target). The breach opens to the side rather than the bottom, as seen with the previous grenade launcher, to accommodate longer 40mm grenades than could be fired through the M203.

The Marine Corps intends to begin fielding the new grenade launcher in fiscal year 2020. It has been designed to work with new weapons platforms like the Marine Corps‘ M27 infantry automatic rifle, ensuring it will integrate seamlessly into infantry units even as other platforms trickle their way into service.