It is 58 years since the US Army adopted a new offensive grenade, the M111 Offensive Hand Grenade is intended to provide enhanced capability in confined spaces and augment the venerable M67 fragmentation grenade which has been in service since 1968. The new grenade was developed by the Army’s Capabilities Program Executive Ammunition and Energetics in conjunction with the U.S. Army Combat Capabilities Development Command Armaments Center at Picatinny Arsenal. The new M111 replaces the Mk3A2 hand grenade, which the US Army notes has a body containing asbestos and is now considered ‘obsolete’. The M111 has been in development since at least 2020, appearing in the US Army’s Grenades and Pyrotechnic Signals book in 2021.
The desire for a new blast grenade may have been somewhat informed by lessons learned from Ukraine where troops have been manufacturing their own enhanced blast grenades. M111 has an intriguing octagonal shape with a tapering neck, not dissimilar to the specialist Mk14 anti-structure grenades – which have also seen use in Ukraine.
“One of the key lessons learned from the door-to-door urban fighting in Iraq was the M67 grenade wasn’t always the right tool for the job. The risk of fratricide on the other side of the wall was too high,” explained Col. Vince Morris, Project Manager Close Combat Systems, CPE A&E. “But a grenade utilizing BOP can clear a room of enemy combatants quickly leaving nowhere to hide while ensuring the safety of friendly forces.”
What Are Offensive & Defensive Grenades?
Essentially, offensive grenades rely on blast while defensive grenades use fragmentation. Blast grenades like the M111 limit the radius of fragments, this is useful in confined spaces where friendly forces may be near the blast. It also allows the user to quickly follow up and the nature of blast over-pressure means that even an enemy behind moderate cover inside a room where a blast grenade has detonated is likely to feel increased effect. Conversely, defensive fragmentation grenades like the M67 spread out a wide arc of lethal fragments from the body of the grenade. This is ideal for engaging enemy in the open who may be assaulting the user’s position. These are best employed from cover where the user and friendly forces are less at risk of being wounded by their own grenade. This is something that has been part of Russian doctrine for decades with the RGN offensive grenade and RGO defensive grenade complimenting each other.
The M111 is 4.41 inches in length and 2.37 inches in diameter and is manufactured by Texas-based Day & Zimmermann, Inc.. It appears to use the same M213 pyrotechnic delay fuze and safety lever assembly – meaning the new grenade has the same five-step arming process as the M67, simplifying training, manufacture and logistics. From the markings seen in the new photographs of the grenade the M111’s filling is the RDX-based Composition A-3 high explosive with Aluminum powder, the M67 uses Composition B. The Aluminum powder acts to enhance the Comp A-3’s explosive energy. The amount of explosive filling hasn’t been disclosed but the grenade’s overall weight is listed as 12.6 oz, so the filling weight can be estimated to be around ??? It’s also worth noting that US Army’s Grenades and Pyrotechnic Signals book, published in 2021, listed the explosive filling as PAX-3 suggesting a subsequent move to Comp A-3.
The new grenade provides soldiers with the ability to fight more effectively in close-quarter and urban environments by leveraging blast overpressure, instead of fragmentation to deliver lethality. It provides an alternative to using the M67 high explosive fragmentation grenade which in close-quarters could injure the user or any friendlies in the blast radius. In addition to the new M111 grenade a new inert, blue-colored, training grenade – the M112, has also been adopted.
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This is an expanded version of an earlier version of this article published at Overt Defense.
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