Grenade launcher
A grenade launcher is a weapon that launches a grenade to greater distances, more accurately, and faster than a soldier could throw by hand. Man-portable grenade launchers can either come in the form of a standalone weapon (either single-shot or repeating weapons), or mounted under the barrel of a rifle. Alternatively, many rifles have been designed to fire rifle grenades from their muzzle.
Description
Most grenade launchers are man-portable, shoulder-fired weapons, usually mounted on a rifle such as the AK-47 or M16. However, many can be used independently, such as the M79 and AG36. These are almost always single shot, manually reloaded weapons firing 30–40 millimeter caliber grenades which rarely resemble hand grenades, but look more like miniature artillery shells. The most standard grenade round today is the 40mm grenade, which has a wide variety of applications in man-portable and vehicle mounted weapons systems. With this standardization, there are many new 'specialty' grenades available, from rounds that can be used as a flare, infrared flare, or even a video camera that surveys the battlefield from a bird's eye view. There are also heavier examples, including automatic grenade launchers for ground and vehicle use, such as the American Mk 19. Capable of a relatively high rate of fire, these automatic grenade launchers are used for suppressive fire and to destroy or disable light vehicles and buildings. Some armored fighting vehicles also mount grenade launchers as a means of defense, usually firing 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.
Types
The man-portable grenade launcher can either come in the form of a standalone weapon (either single-shot or repeating weapons, the latter resembling a large revolver); or an underbarrel weapon which is permanently mounted to the rifle. Alternatively, many rifles have been designed to fire grenades from their muzzle, using either a special blank propellant cartridge or a central hole through the grenade allowing the bullet to pass through. This system has two key advantages: the grenade can generally be made larger and more powerful as compared to underbarrel or standalone weapons, and the rifle's weight and handling characteristics are not affected as with underbarrel systems. The disadvantage of this method is that when a soldier wants to launch a grenade he must unload the weapon and then load the propellant cartridge and grenade. If he is surprised by a close-range threat while preparing to fire the grenade, he has to reverse the above procedure and cannot immediately react with rifle fire. In underbarrel systems, the rifle portion and launching portion of the weapon can both be carried loaded and ready to fire. Underbarrel tubes generally have their own trigger and use the rifle's magazine as a grip for the firing hand. To fire, one simply changes grips, disengages the safety and pulls the trigger. In most systems the barrel either slides forward or pivots to the side to allow reloading. For aiming, the M203 mounts either a flip-up rear sight, which is notched for different ranges and utilizes the rifle's existing front sight, or a "quadrant" sight which mounts to the side of the carrying handle. Recoil from such weapons is significant, comparable to a high-power shotgun.
Examples of modern man-portable grenade launchers are the M203 and GP-30, which mount to service rifles. Another type of man-portable grenade launcher is the M32 'six shooter' grenade launcher and its cousins, which is able to fire six grenades in quick succession from a cylindrical chamber, this classification of firearm is often referred to as a Multi Shot Grenade Launcher, or MSGL. Automatic launchers include the Mk 19, AGS-17, and the HK GMG, which all fire at a higher velocity than related shoulder-fired grenades. Modern developments tend toward smaller, faster, and massed grenade fire. The XM25 is a shoulder-fired, magazine-fed semi-automatic launcher firing 25 mm projectiles. It was originally a component of the XM29 OICW program, but modified to a larger caliber. Its heavy equivalent is the XM307 ACSW automatic grenade launcher that is easily convertible between the 25 mm grenade ammunition and standard .50 BMG cartridges. Both are intended to fire programmable "smart" grenades capable of being set to explode at a certain distance from launch or at a certain height above the ground. This gives the ability to hit targets inside of rooms or behind hard cover that would normally not be reachable by small arms fire.