The 40 mm grenade is a military grenade caliber for grenade launchers in service with many armed forces. There are two main types in service: the 40x46mm, which is a low-velocity round used in hand-held grenade launchers; and the more powerful 40x53mm, used in heavier, mounted and crew-served weapons. The cartridges are not interchangeable.
The more powerful 40x53mm is used in grenade launchers mounted on vehicles or tripods, often with automatic firing capabilities 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 and fired automatically. The 40x53mm is also used in some mounted helicopter grenade launcher systems, which are electrically powered and primed.
A new 40x51mm 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 40x46mm rounds.
Martin Electronics Inc. (MEI) manufactures a new range of improved 40x46mm grenades. They claim that their HELLHOUND round has an effective radius twice that of the standard M433 High Explosive Dual Purpose (HEDP) round.
Martin Electronics Inc. (MEI) manufactures a new range of improved 40x46mm grenades. They claim that their MERCURY round has double the effective range out to 800m of the HELLHOUND, but with slightly less fragmentation.
U.S. military rounds designated specifically for the M79 launcher includes:
U.S. military rounds designated specifically for the M203 launcher includes:
Ripple Effect – formerly Milkor – the South African designers of the Milkor MGL ("M32 MGL" in U.S. service) developed a new "Extended Range Low Pressure" (ERLP) 40x51mm cartridge. This round extends the range of the 40 mm grenade from 400 m (440 yd) to 800 m (880 yd). A new version of the MGL, the XRGL40 is chambered for the new round, but can still fire the regular 40x46mm grenade.
U.S. military rounds designated specifically for the Mk 19 grenade launcher includes:
U.S. military rounds designated specifically for the Mk 47 grenade launcher includes:
The MK285 consists of a 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 app. 23 meters. the safe and arm in the fuze is entirely mechanical.
Basic principle: The round is programmed to airburst over the target, the fuze counts down the programmed time via its built in electronics. if a programming doesn't occur, the round will point detonate at impact.
The round does also have a built in Self destruct.
The round can also be fired in any Automatic grenade launcher.
Other weapons using 40mm rounds are the Corner Shot 40 grenade launcher, the Milkor MGL Mk-1S Multiple Grenade Launcher, the Penn Arms PGL65-40 'Fourkiller Tactical Model' 40 mm Multiple Grenade Launcher, the Heckler & Koch AG36, 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 Russian GP-30 Obuvka, GP-25 Kastyor, and BG-15 Mukha use a unique type of 40 mm grenade. These grenades are caseless, holding their own propellant within the body of the grenade. The Russian 40 mm grenades are not interchangeable with U.S. 40x46mm and 40x53mm weapons. They also developed a silenced 30mm grenade launcher, the BS-1 "Tishina", using multi-rounds blank cartridge magazine meant to ignite the 30mm HE-DP caseless grenade.
The Metal Storm 40 mm Weapon System is a 4-barrel, 16-round weapon system that also uses 40 mm 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.
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 ERPL or 40x53mm 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 XM320 and the FN SCAR's Mk13 Mod0 EGLM. The EGLM is innovative, as it 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 they want. 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 40 mm 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 its a training round), meaning that there is no unexploded ordinance left to clean up on the range and heavy metals in the fuse don't leak into the ground. The MK281 was introduced into parts of the US Armed Services because of an executive order mandating that they buy green ammunition. The MK281 is manufactured by an American subsidiary of the Rheinmetall Group.