For nearly six decades, the M67 fragmentation grenade has been the primary hand grenade American soldiers have carried into combat. That changes now.
The Army cleared the M111 Offensive Hand Grenade for full material release Tuesday, marking the first new lethal hand grenade to enter service since 1968. Developed at Picatinny Arsenal, N.J., the weapon gives soldiers a purpose-built tool for urban combat, where the fragmentation grenade that has carried the force since the Vietnam War can become as dangerous to friendly troops as to the enemy.
The Army’s New Hand Grenade
The M111 does not rely on shrapnel to kill. Instead, it harnesses blast overpressure, a wave of force generated by detonation that behaves very differently inside a closed room than fragmentation does. Walls, doorframes and furniture offer no refuge from it.
The M67 fragmentation grenade, the round baseball-shaped weapon soldiers have carried since Vietnam, sends steel fragments outward in all directions at detonation. In the open, that makes it lethal at range. Inside a building, the same fragments can be stopped, deflected or scattered unpredictably. Anything on the other side of a thin wall is as much at risk as the intended target.
For urban combat in the modern battlespace, the M111 aims to negate enemy cover while protecting the assault troops.
"One of the key lessons learned from the door-to-door urban fighting in Iraq was that the M67 grenade wasn't always the right tool for the job," said Col. Vince Morris, project manager for Close Combat Systems at the Capabilities Program Executive Ammunition and Energetics. "The risk of fratricide on the other side of the wall was too high."
The M111 addresses that problem head-on. Blast overpressure radiates through enclosed space and cannot be stopped by interior walls the way fragmentation can, creating lethal effects that reach every corner of a room. The M67 is not going away, Morris said. In open terrain, soldiers will continue to use it to maximize lethal fragment effects. The two grenades are designed to complement each other.
"We've given our Soldiers and joint warfighters the flexibility to determine in the field which type of grenade will best suit the current situation they are facing, be it open space or confined area," said Tiffany Cheng, a DEVCOM Armaments Center engineer who helped develop the M111 at Picatinny Arsenal.
The M67 Hand Grenade
The M111 formally replaces the Mk3A2 offensive hand grenade, a concussion-type weapon that entered service alongside the M67 in 1968. Unlike the M67, which remains in the active inventory, the Mk3A2 was long ago restricted from use because its body contains asbestos. The M111 uses a plastic body that is fully consumed during detonation, eliminating the health hazard.
The M67's longevity reflects both its reliability and the difficulty of improving on a simple, proven design. The round grenade replaced the M33-series that American soldiers carried in Vietnam, itself a successor to the M26 grenades soldiers threw in Korea. The M67 entered service in 1968 as U.S. forces were deep in combat operations in Southeast Asia.
Its steel body contains 6.5 ounces of Composition B explosive, a mixture of RDX and TNT. It has a lethal radius of 5 meters, a casualty-producing radius of 15 meters and fragments capable of reaching 230 meters. In more than 55 years of continuous service it has been used in every major American conflict from Southeast Asia through Afghanistan and Iraq.
The Army designed the transition to cause minimal disruption to existing training operations. Both the M111 and M67 use the same five-step arming process. The M111 shares fuze components with the M67 and its training counterpart, the M69. A soldier alternating between the two weapons will find that the procedure for arming and using them remains the same.
"By standardizing the arming process and the fuzing, the Army saves taxpayer money without sacrificing lethality on the battlefield," Morris said. "This is the kind of acquisition reform that is currently underway throughout the Army acquisition enterprise."
Grenades for Two Different Purposes
The concept of dual grenades is not new. The Soviet military built the offensive-defensive grenade split into its doctrine decades before the United States did and even named the weapons accordingly. The F-1 defensive grenade was designed for use from soldiers behind cover. Its thick steel body produced lethal fragmentation that reached well beyond a soldier's throwing range, perfect for troops holding a bunker or building against enemy assaults.
The RGD-5 offensive grenade, which entered Soviet service in 1954, was engineered with a tighter fragmentation radius. This allowed a soldier to throw it while moving against enemy troops in the open without catching the blast.
Afghanistan exposed the limits of both. Long fuze delays gave Mujahideen fighters time to react or throw grenades back. Steep mountain terrain also sent them rolling back toward Soviet lines. The Soviets responded with a new matched pair in the mid-1980s.
The RGN offensive grenade kept the fragmentation radius limited, protecting the assaulting soldier. The RGO defensive grenade was built to saturate open ground with fragments from a covered position. Both used the same dual-function fuze that could detonate on contact or trigger automatically at four seconds, eliminating the delay problem entirely.
The pair of Soviet-era hand grenades is still in service with Russian and Ukrainian forces in combat today. Combat troops have put both to use, whether assaulting fortifications and buildings or defending a trench from an enemy assault. The U.S. Army is now adopting the same capabilities, recognizing that no single grenade can answer every situation a soldier faces downrange.
