The 40mm grenade is a military grenade caliber for grenade launchers in service with many armed forces. There are two main types in service: the 40×46mm, which is a low-velocity round used in hand-held grenade launchers; and the high-velocity 40×53mm, used in mounted and crew-served weapons. The cartridges are not interchangeable. Both 40mm cartridges use what the US Army during the Vietnam War called the High-Low Propulsion System.
The more powerful 40×53mm is used in automatic grenade launchers mounted on tripods, vehicles or helicopters, such as the Mk 19 grenade launcher, the Mk 47 "Striker" 40 mm Grenade Machine Guns (GMGs), the Heckler & Koch GMG or the South African Vektor Y3 AGL. In these roles, the rounds are linked together with a metallic disintegrating link.
A new 40×51mm cartridge recently (2007) developed in South Africa provides a more powerful alternative for hand-held weapons without increased recoil. A new version of the Milkor MGL chambered for the new round remains backward compatible with existing 40×46mm rounds.
U.S. military rounds designated specifically for the M79 launcher includes:
- High Explosive (HE): M381, M386
- Airburst: M397, M397A1
- Twenty 24 grain metal pellets: M576
- CS gas: M651
- Practice: M781
U.S. military rounds designated specifically for the M203 launcher includes:
- High Explosive (HE): M381, M386, M406, M441
- High Explosive Dual Purpose (HEDP): M433
- Airburst: M397, M397A1
- Buckshot: M576 (Twenty 24g metal pellets)
- Thermobaric: XM1060
- Star parachute (flare): M583A1
- Star cluster (flare): M585 (white), M661 (green), M662 (red)
- CS gas: M651
- Smoke Canopy: M676 (yellow), M680 (white), M682 (red)
- Ground Marker (smoke): M713 (red), M714 (white), M715 (green), M716 (yellow)
- Practice: M781
- Infra-red illumination: M992
- Non lethal (crowd control)
- Sponge Grenade (crowd control)
It is a grenade caliber designed in Poland, and used in Pallad wz. 74 underbarrel grenade launchers (used with AK family rifles in use in Polish Army like the AKM/AKMS, Tantal and Beryl) and Pallad-D wz. 83 Grenade launcher (standalone variant fitted with standard pistol grip and folding stock from AKMS assault rifle). The construction is similar to one used in 40×46 but grenades are not fully interchangeable.
Mk 19 Mod 3
U.S. military rounds designated specifically for the Mk 19 grenade launcher includes:
- High Explosive (HE): M383, M384
- High Explosive Dual Purpose (HEDP): M430I
- High Velocity Canister Cartridge (HVCC): M1001
- Practice: M385I, M918
- Dummy: M922/M922A1
Mk 47 Mod 0
U.S. military rounds designated specifically for the Mk 47 grenade launcher include:
- MK285, Programmable Prefragmented High Explosive/Self-Destructible (PPHE/SD)
The MK285 consists of an electronic programmable fuze, a prefragmented warhead and a propulsion system. the fuze is programmed through the fire control of the gun. the fuze is mechanically armed at approximately 23 meters.
The round is programmed to airburst over the target and the fuze counts down the programmed time via its built in electronics. If an unprogrammed round is fired, it will detonate on impact.
The projectile has a built in self-destruct and can be fired by any automatic grenade launcher.
Other weapons using 40mm rounds are the Corner Shot 40 grenade launcher, the Defcpm LLC XL201A1 rail mounted launcher (Defcom sales brochure, dated 2010), the Milkor Multiple Grenade Launcher range, the Penn Arms PGL65-40 "Fourkiller Tactical Model" 40mm Multiple Grenade Launcher, the Heckler & Koch AG36, Heckler & Koch AG-HK416, the Heckler & Koch GMG grenade autocannon and the Heckler & Koch HK69A1. There is also the CIS 40 AGL and 40LWAGL from Singapore's ST Kinetics. The Daewoo K4 Grenade Machine Gun is in service with the South Korean Armed Services.
The Soviet GP-25 Kostyor and GP-30 Obuvka and Russian GP-34, BG-15 Mukha and RG-6 use a unique type of 40mm grenade. These grenades are caseless, holding their own propellant within the body of the grenade. The Soviet 40mm VOG-25 grenades are not interchangeable with U.S. 40×46mm and 40×53mm weapons.
The Soviet Union also developed a silenced 30mm grenade launcher, the BS-1 "Tishina", using a multi-round blank cartridge magazine meant to ignite the 30mm HE-DP caseless grenade.
The Metal Storm 40 mm Weapon System is a four-barrel, 16-round weapon system that also uses 40mm grenades (stacked), and is designed for mounting on an unmanned ground vehicle. Initial trials are under way to determine suitability for mounting on unmanned aerial vehicles.
Multi-caliber grenade launchers
As one of the earliest barrel-mounted grenade launchers reaching mass production, the M203 has a major problem: it cannot be loaded with high-powered or specialized grenades, such as Milkor ERLP or 40×53mm grenades, because of its slide-locking barrel. The manufacturers working on replacements of the M203 had to come up with new ideas so this would be possible with new issued grenade launchers. This resulted in two innovative designs, like the side-loading M320 grenade launcher and the FN SCAR's Mk13 Mod0 EGLM. The EGLM opens like the M203 but the barrel can also be pivoted right or left, allowing left and right-handed shooters to load it quickly with any ammunition. The HK AG36 launcher has a similar setup where the barrel turns so that the breech is facing the user.
The MK281 is a new type of 40mm target practice grenade ammunition that has been accepted for use into the United States Marine Corps and the United States Army. It is "green" because it is non-toxic and non-dud producing (since it is a training round), meaning that there is no unexploded ordnance left to clean up on the range and heavy metals in the fuse do not leak into the ground. The MK281 was introduced into parts of the U.S. Armed Forces because of an executive order mandating that they buy green ammunition. The MK281 is manufactured by an American subsidiary of the Rheinmetall Group.
- Grenade launcher
- HK GMG
- M203 grenade launcher
- M79 grenade launcher
- Milkor MGL
- United States 40 mm grenades
- Daewoo K4
- Milkor (Pty) Ltd
- 40mm Low-Velocity Grenades
- Defense Review overview of Mk 47 Mod 0 'Striker' 40mm Grenade Machine Gun
- Defense Review overview of Corner Shot 40 personal grenade launcher
- Defense Review overview of Penn Arms PGL65-40 'Fourkiller Tactical Model' 40 mm Multiple Grenade Launcher
- Penn Arms data page for PGL65-40 6-Shot Grenade Launcher
- Defense Review overview of Metal Storm 40mm Weapon System
- Future Weapons: MEI Mercury 40MM Grenade