Rifle grenade
A rifle grenade is a grenade that uses a rifle-based launcher to permit a longer effective range than would be possible if the grenade were thrown by hand.
The practice of projecting grenades with rifle-mounted launchers was first widely used during World War I and World War II and continues to the present, with the term "rifle grenade" now encompassing many different types of payloads including high explosive, fragmentation, anti-tank warheads, concussion, smoke, incendiary, and flare missiles.
Rifle grenades have largely been supplanted in the infantry fire support role by a combination of grenade launchers and disposable anti-armor rockets.
History
Early use
Adaptation of grenades for use in rifles began around the 18th century, when cup-shaped dischargers were fitted to the barrels of flintlock muskets, with the grenades propelled by the force of a blank cartridge. During the early 20th century a Japanese Colonel Amazawa experimented with rifle fired grenades during the Battle of Port Arthur in the Russo-Japanese War, and the idea was further used by the Spanish, though the French were the first to put it to widespread use during the trench warfare of World War I.World War I
In 1908, Frederick Marten Hale patented the rod grenade. "A simple rod was attached to a specialized grenade, inserted into the barrel of a standard service rifle and launched using a blank cartridge." The British did not immediately adopt the idea and entered World War I without any rifle grenades. However, as soon as the trench warfare started, there was a sudden need for rifle grenades. The British government purchased a rodded variant of the No 2 grenade as a temporary solution.By 1915, Hales had developed the No 3, which is commonly known as the Hales rifle grenade. The Hales grenade was improved throughout World War I to make it more reliable and easier to manufacture. However, production of the grenade was slow. In order to speed rod grenades to the front, the British also made rodded versions of the Mills bomb.
Although a simple approach, launching a rod grenade "...placed an extreme amount of stress on the rifle barrel and the rifle itself, resulting in the need to dedicate specific rifles to the grenade launching role, as they quickly became useless as an accurate firearm. This led to the search for an alternative and resulted in the reappearance of the cup launcher during the latter years of World War I". After World War I, the rod-type rifle grenade was declared obsolete and the remaining Hales were replaced with gas check equipped Mills Bombs shot from a rifle via a cup launcher.
The French grenade, named the V-B grenade after its inventors, Viven and Bessières, was fired from the standard service rifle with the use of a special adapter and a standard cartridge, providing an effective range of around. The grenade had a hollow through the middle, allowing the bullet to pass through, while the muzzle blast was captured by the launching device and used to propel the grenade. The bullet, after passing through the body of the grenade, struck a small plate that ignited the primer. This then lit the fuse in the grenade, providing an eight-second delay before detonation. It could be fired from the shoulder, but due to the heavy recoil and poor balance of the rifle fitted with the grenade, it was more common to fire it with the butt of the rifle resting on the ground, and either held at an appropriate angle, or resting on a tripod. The rifle grenade was useful in offense, particularly in attacking sandbag fortified machine gun nests, as well as in defense. Eight men armed with rifle grenades could fire 150 shots in a minute, providing a heavy barrage to break up an attacker's lines.
Upon entering World War I, the United States attempted to adopt the V-B grenade, but this was not very successful. The difference in bore diameter between the French and American service cartridges meant that the grenade had to be re-designed with a smaller hole, but even this was not sufficient to ensure reliable functioning, due to differences in bullet design. The American bullet would often break apart in the grenade, and this led to the V-B derived grenade design being scrapped in May 1918.
The next United States attempt at a rifle grenade was to return to and develop an improved rod-grenade. The Babbitt grenade, developed by Colonel E. B. Babbitt of the U.S. Ordnance Department, used a long stem projecting from the rear of the grenade, which was slipped into the barrel of the Springfield 1903 rifle, and propelled with a special blank cartridge. The stem was calibrated with a number of grooves and a split ring, which allowed the user to set the grenade to slide a certain distance into the muzzle of the rifle. When the stem was inserted only part way, the chamber pressure upon firing was reduced, propelling the grenade a shorter distance. When fired at a 45-degree angle, ranges from were possible; with the rifle angled at 80 degrees, ranges as short as were possible. In addition to providing the force to propel the grenade, the gases from firing were directed through a hollow in the stem, and provided force to arm the grenade. Once armed, the grenade had a heavy plunger that would detonate the grenade upon impact.
World War II
After World War I, the rifle grenade was steadily modified to increase its effectiveness when launched from a rifle.In 1928, the Italian Army adopted an unusual cup-type rifle grenade launcher bolted to the side of a normal Carcano 6.5 mm carbine, the Moschetto di Fanteria Mod. 91/28 con Tromboncino. In use, the rifle's bolt was removed and installed in the launcher chamber. The rifle was placed butt-first against the ground, a grenade loaded down the launcher's muzzle and standard rifle round loaded into the grenade launcher's chamber. When fired, the bullet was trapped, the neck of the cartridge case expanded and the gases passed into launcher's barrel through four holes providing the energy needed to launch the grenade. After the grenade was launched, the chamber was opened, ejecting the spent cartridge case and making the bullet fall out. The necessity of changing the rifle bolt kept the rifle out of use until the bolt could be replaced, a slow and clumsy procedure. The bolt-changing procedure could also result in lost rifle bolts in the heat of battle, putting the weapon out of action completely. As a result, this design was not adopted by any other nation. Today, it can be seen as an early, if unsuccessful ancestor of modern under-barrel grenade launchers such as the M203.
File:A member of the Home Guard demonstrates a rifle equipped to fire an anti-tank grenade, Dorking, 3 August 1942. H22061.jpg|thumb|A member of the British Home Guard demonstrates a rifle equipped to fire a No. 68 anti-tank grenade
File:M1 Garand rifgren-shooting line.jpg|thumb|left|An M7 grenade launcher with M9 rifle grenade fitted on the end of an M1 Garand rifle
The Japanese military continued to experiment with rifle and hand-thrown grenades between the wars and would adopt a family of fragmentation grenades with almost universal adaptability. Introduced in 1931, the Type 91 fragmentation grenade could be thrown by hand, fired from a cup-type grenade launcher, discharged by a lightweight mortar-like projector. or fitted with tail-fin assembly and fired from a spigot-type rifle grenade launcher.
The spigot-type grenade launchers were used by Japanese Special Naval Landing Forces to launch an anti-tank finned grenade. They were also used to propel Type 91 hand grenades fitted with tail-fin assemblies. These grenades had wood-bulleted launching cartridges stored in their tail-fin assemblies. The cartridges are fired from the rifle and the wooden bullets are trapped by the tail-fin assemblies launching and arming the grenades. These launchers are not numbered, and production figures are not available and examples of spigot grenade launchers are rarely encountered.
In 1939, the Japanese introduced the Type 100 grenade discharger for the Type 38 and Type 99 Arisaka rifles. It launches standard Type 91 and Type 99 hand-grenades. The launcher is somewhat unusual in that rather than using the more common cup designs it is a gas trap system, meaning that it incorporates a barrel extension which taps off excess propellant gases to launch the grenade from a cup offset from the barrel. This has the advantage that standard rifle cartridges could be used along with the standard hand-grenades which simplified logistics, at the expense of increased weight and decreased efficiency. The effective range is approximately.
In 1940, Britain put the first anti-tank grenade into the field during World War II the No. 68 AT grenade, which was one of the first "of any" type anti-tank weapons with a shaped charge or high-explosive anti-tank type warhead. The design of the warhead was simple and could penetrate of armor in 1940. The simple fins gave it some stability in the air and detonation occurred on impact.
In 1942, an attachable rifle grenade launcher called the Gewehrgranatengerät or Schiessbecher was introduced that was developed based on rifle grenade launcher models designed during World War I. The Schiessbecher cup-type rifle grenade launcher could be mounted on any Karabiner 98k and was intended to replace all previous rifle grenade launcher models. The rifle grenade launcher could be used against infantry, fortifications and light armored vehicles up to a range of 280 m. For these differing tasks, several specialized grenades with accompanying special propelling cartridges were developed for the 1,450,113 produced Schiessbecher rifle grenade launchers. The rifle grenade-propelling cartridges fired a wooden projectile through the barrel to the rifle grenade that, upon impact, automatically primed the rifle grenade. The Schiessbecher could be mounted on the Karabiner 98a, G98/40, StG 44, and FG 42
The Japanese would also adopt a version of the German Schiessbecher grenade launcher. The Type 2 rifle grenade launcher was an attachment for the Type 38 and Type 99 rifles that allowed them to fire special hollow charge grenades. Two grenades were produced for the launcher: a grenade and a larger, grenade, both designated Type 2. The launcher sits over the end of the barrel, held in place with a clamping device. A special crimped blank cartridge or wooden bullet is used to fire the grenades.
In the years just before World War II, the United States adopted the spigot-type 22 mm rifle grenade launchers. These launchers are attached to a rifles muzzle, in the form of a detachable adapter. As with most rifle grenades, it is propelled by a blank cartridge inserted into the chamber of the rifle. A grenade can range from powerful anti-tank rounds such as the M9 rifle grenade, to simple finned tubes with a fragmentation hand grenade attached to the end such as the M1 grenade adapter. The "" refers to the diameter of the base tube which fits over the spigot of the launcher, not the diameter of the warhead section, which is much wider.