A grenade launcher is used as a close support weapon for infantry, intended to bridge the gap between the maximum throwing distance of a hand grenade and the closest range of supporting mortar fire.
The first grenade launchers used blank cartridges to propel a grenade placed on the end of a rifle barrel. That design was used through World War II and the Korean War. By the time of the Vietnam War, a separate grenade launcher weapon with its own 40mm ammunition had been fielded, resembling a large bore shotgun. Further development of the concept led to grenade launchers that attach under the barrel of a host rifle/carbine, adding the firepower of the grenade launcher without any loss of function for the rifleman.
Rifle grenade instruction at the USMC School of Infantry - East, Camp Lejeune, NC. Marine is preparing to fire a hand grenade with rifle adapter.
Today in WW II: 18 Nov 1940 Alfred Loomis suggests the electronic air navigation system which was later developed into LORAN [long range navigation system] at MIT. More↓
During World War II grenade launchers were an accessory, associated with the rifle and carbine, used by all infantry. The M1 grenade launcher was made for the M1903 Springfield rifle. The M7 grenade launcher, available in 1943, was designed for use with the M1 Garand rifle as in the drawing to the left. The M7 did not allow semiautomatic operation of the M1 resulting in its replacemeny by the M7A1 (or M7A2 and M7A3) which did.
The grenade launcher attached to the rifle like a bayonet with its tube over the muzzle, forming an extension to the barrel. A similar device, the M8, was made for the M1 Carbine.
The rifle grenade was mounted onto the launcher, set to the correct ring to determine the range. A special blank rifle cartridge was used to fire the grenade (M3 .30-06 cartridge for the Garand). The grenade cartridge produced heavy recoil so the recommended firing position was with the rifle (or carbine) butt on the ground, with the stock turned to the side, to avoid injury to the soldier or damage to the weapon.
Special rifle grenades were produced (photo, right) and there was also an adaptor that converted a standard fragmentation hand grenade for use with the rifle launcher (top photo).
M79 Grenade Launcher
Disassembly diagram for the M79 40 MM Grenade Launcher.
The M79 40mm Grenade Launcher was a short, single barrel gun designed to accurately fire a 40mm grenade. It was used extensively during the Vietnam War. However, the single shot nature of the M79 meant a slow rate of fire and limits on ammunition quantities soon left the M79-equipped soldier with nothing to fire. These factors led to the development of under-barrel grenade launchers, making the grenade capability an addition to the fire capacity of the rifle.
The XM148 Grenade Launcher was an experimental design that combined the M79 Grenade Launcher and M16 rifle. Limited quantities were produced and fielded in 1967, but the XM148 was found to be unsatisfactory in tests and combat in Vietnam. The concept of an under-barrel grenade launcher attachement for the M16 was welcomed and led on to the successful M203 Grenade Launcher.
M203 Grenade Launcher
The M203 40mm Grenade Launcher was designed and procured as the replacement for the M79 grenade launcher, designed to be mounted on the M16 rifle, the same concept as the unsuccessful XM148. For more information, see the Olive-Drab.com page on the M203 Grenade Launcher.
M320 Grenade Launcher
The M320 40mm Grenade Launcher is the replacement of the M203 series of grenade launchers on M16 Rifles and M4 Carbines. Like the M203, it attaches under the barrel of the rifle or carbine. Uniquely, the M320 and can convert to a stand-alone weapon. For more information, see the Olive-Drab.com page on the M320 Grenade Launcher.
M32 Multiple-Shot Grenade Launcher
The M32 Grenade Launcher, Multi-shot, 40mm provides the U.S. Marines with increased firepower to dominate an area of operation or to defeat specific targets in battle. Its reloadable cylinders can hold up to six cartridges at once and can be quickly reloaded. For more information, see the Olive-Drab.com page on the M32 Multiple-Shot Grenade Launcher.
There are many fine websites that have additional information on this
topic, too many to list here and too many to keep up with as they come and go.
Use this Google web search form to get an up to date report of what's out there.
For good results, try entering this: grenade launcher. Then click the Search button.