The US military is getting its first new hand grenade in 40 years as engineers at the US Army Armament Research, Development, and Engineering Center (ARDEC) at Picatinny Arsenal, New Jersey, work on a safer multi-purpose design. Called the Enhanced Tactical Multi-Purpose (ET-MP) hand grenade, it will allow soldiers to choose between concussive or fragmentation blasts with the flip of a lever.

Though many people think of grenades as little green pineapples with pins sticking out of them, there are actually many different types for many different jobs. There are incendiary grenades for destroying equipment, gas grenades for crowd control, smoke grenades, stun grenades, anti-tank grenades, and even illumination grenades to cast a bit of light on the subject.

The two main lethal types carried by foot soldiers are concussion and fragmentation grenades.

Concussion grenades are listed as "offensive" because they kill by means of blast. They have a small danger radius, so soldiers can use them while advancing in the open without fear of being caught in the blast wave.

Fragmentation grenades, on the other hand, are "defensive." In addition to a high-explosive charge, the fragmentation grenade has a sleeve filled with ball bearings or is wrapped in wire or a metal casing that shatters into lethal bits on detonation. These typically have a danger radius of 15 m (49 ft), so soldiers have to be behind cover when using them.

According to the Army, the US inventory of lethal grenades has consisted solely of the M67 fragmentation grenade and its variants since 1975. In that year, the MK3A2 concussion grenade was withdrawn from service – ironically, because of an asbestos hazard.

The ET-MP is aimed at replacing both fragmentation and concussion grenades with a safer, more flexible design. At the flip of a lever, the ET-MP changes from one mode to the other, reducing the need for troops to carry multiple grenades, yet having the one to suit the current situation.

ARDEC says that the ET-MP is the result of five years development based on requests and feedback from troops wanting an improved grenade, as well as input from Infantry School representatives. Aside from its dual mode, it's also the first US ambidextrous grenade. Previous hand grenades were designed for right handers, which made it difficult for southpaws to use without special instruction.

"We received direct input from the Army and Marine Corps early on, which was critical in ensuring the new arming and fuzing design was user friendly," says Matthew Hall, Grenades Tech Base Development Lead. "With these upgrades in the ET-MP, not only is the fuze timing completely electronic, but the detonation train is also out-of-line. Detonation time can now be narrowed down into milliseconds, and until armed, the hand grenade will not be able to detonate."

The ET-MP is expected to go into service in five years.

Source: US Army