Stand-alone 37 mm riot gun The earliest examples of stand-alone grenade launchers in the modern sense were breech-loading
riot guns designed to launch
tear gas grenades and
baton rounds, such as the
Federal Riot Gun developed in the 1930s. One of the first examples of a dedicated breech-loading launcher for unitary explosive grenade rounds was the
M79 grenade launcher, a result of the American
Special Purpose Individual Weapon program (specifically the 40×46mm grenade round developed during
Project NIBLICK, applying the German-developed
high–low system to produce manageable recoil). The goal for the M79 was the production of a device with greater range than a
rifle grenade but more portable than a
mortar. Such single-shot devices were largely replaced in military service with underbarrel grenade launchers, removing the need for a dedicated
grenadier with a special weapon. Many modern underbarrel grenade launchers can, however, also be used in standalone configurations with suitable accessories fitted; this is of particular preference for groups using
submachine guns as their primary armament, since it is rarely practical to mount an underbarrel launcher on such a weapon. Single shot launchers are also still commonly used in
riot control operations. Heavier multi-shot grenade launchers like the
ARWEN 37 are used as
tear gas and smoke projectors in riot control, while military launchers like the
Milkor MGL are used to provide heavy sustained firepower to infantry; most such devices, dating back to the
Manville machine-projector, use a revolver-style cylinder, though a handful of pump-action weapons built like oversized shotguns, such as the
China Lake grenade launcher and
GM-94, also exist. Magazine-fed semi-automatic designs such as the
Neopup PAW-20 and
XM25 CDTE have also been created for military use, using smaller rounds (respectively 20 and 25mm) for purposes of practicality in terms of the size of the magazine, and reduced collateral damage compared to 40mm rounds. The arms manufacturer
Rheinmetall plans to start serial production of their magazine-fed fully-automatic grenade launcher SSW40 later in 2025.
Attached attached to an
M16A1 with a practice round Since grenade launchers require relatively low internal pressure and only a short barrel, a lightweight launcher can be mounted under the barrel of a traditional
rifle; this type of device is referred to as an
underbarrel or
underslung grenade launcher. This reduces the weight the soldier must carry by eliminating the grenade launcher's buttstock and makes the grenade launcher available for use at a moment's notice. Underbarrel 40 mm grenade launchers generally have their own trigger group; to fire, one simply changes grips, disengages the safety, and pulls the trigger. In Western systems, the barrel slides forward or pivots to the side to allow reloading; most fire a
40×46mm grenade cartridge. Soviet and Russian launchers are instead loaded from the muzzle, with the cartridge casing affixed to the projectile in the style of a mortar shell. For aiming, underbarrel grenade launchers typically use a separate ladder, leaf, tangent or quadrant sight attached to the launcher or the rifle, either to one side of the handguard or on top of the handguard in between the iron sights. Modern launchers often have the option of mounting more sophisticated aiming systems, such as ballistic rangefinders and day / night sights. As with the M79, the concept of mounting a dedicated grenade launcher to a service rifle has its roots in the
Special Purpose Individual Weapon program; though the experimental Colt
XM148 grenade launcher had been produced earlier, it had proved too problematic to adopt. One AAI submission for SPIW mounted a "simple" single-action, single-shot breech-loading underbarrel grenade launcher in lieu of the required semi-automatic multi-shot device. With refinement, this was adopted as the
M203 grenade launcher in 1968. A variety of lengths of M203 are available along with numerous parts kits to fit it to various rifles aside from the AR15 pattern weapons it was designed for. More modern Western grenade launchers address some of the shortcomings of the M203, such as the sliding breech limiting the weapon's ability to load outsize projectiles and the lack of factory-fitted sight mounts, with designs like
FN Herstal's
ELGM and
Heckler & Koch's
AG36 featuring a swing-out breech to provide better access, integral sight mounts, and built-in support for standalone conversion. A variant of the latter weapon, the
M320 Grenade Launcher Module, was salvaged from the failed
XM8 program and adopted in 2008 as the US military's replacement for the M203. Soviet development of an underbarrel launcher for the AK rifle series began in 1966 and in 1978 produced the
GP-25, a muzzle-loading device for the
AK-74 rifle using a mortar-like grenade round which functions by venting its propellant through holes in the base; this is a variation of the high-low system used by Western rounds, with the base of the projectile acting as the high-pressure chamber and the launcher's barrel acting as the low-pressure chamber. Further developments led to the
GP series of grenade launchers. A number of experimental weapon systems have attempted to produce combination weapons which consist of a permanently attached grenade launcher and a carbine assault rifle, often with the rifle mounted underneath the launcher, most notably the
XM29 OICW, but so far the only such weapon to reach full production is the
S&T Daewoo K11, adopted in limited numbers by the South Korean military.
Automatic An
automatic grenade launcher or
grenade machine gun is a crew-served support weapon which fires explosive rounds in quick succession from an
ammunition belt or large-capacity
magazine. As most are heavy weapons, they are normally attached to a
tripod or vehicle mounting, and as well as being used to provide heavy suppressing fire in the manner of a
heavy machine gun, also have sufficient firepower to destroy vehicles and buildings. Examples include the
Mk 19,
AGS-17, and the
HK GMG. Automatic grenade launchers generally use a higher-velocity round than infantry weapons; NATO launchers use a 40×53mm grenade round rather than the 40×46mm round used by infantry. There are exceptions to this rule: the crank-operated
Mk 18 Mod 0 grenade launcher, a unique example of an AGL which was not fully automatic,
Fixed arrays anti-aircraft vehicle Some
armored fighting vehicles also mount fixed arrays of short range, single-shot grenade launchers as a means of defense. These devices usually fire smoke grenades to conceal the vehicle behind a
smoke screen, though can also be loaded with
chaff,
flares, or
anti-personnel grenades to repel
infantry attacks. Vehicle-mounted smoke grenade launchers are also known as
smoke (
grenade)
dischargers. Some
World War II examples of these devises are the German
Nebelkerzenabwurfvorrichtung,
Nebelwurfgerät,
Minenabwurfvorrichtung and
Nahverteidigungswaffe. ==Ammunition==