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Grenade redirects here. For other uses, see Grenade (disambiguation).

For the alcoholic beverage sold in New Orleans, see hand grenade (drink).

A hand grenade is a small hand-held bomb designed to be thrown. The word "grenade" is derived from the Old French (pome) grenate ("pomegranate"), in reference to the general size of early grenades, and because its shrapnel pellets reminded soldiers of the seeds of this fruit. Grenadiers were originally soldiers who specialized in throwing grenades.

Not all grenades are thrown by hand. Several types are fired from rifles or purpose-designed grenade launchers. For example, tear gas grenades used in riot control are fired from riot guns, and the M203 is a grenade launcher that can be fitted to several types of rifles.

History

Early grenades were usually made of paper, ceramics, or primitive glass and could contain any sort of dangerous or unpleasant substance, ranging from botanical or animal toxins, skin irritants, lye, acids, flammable naptha, petroleum and unstable gunpowder, diseased matter, or parasite eggs (such as locusts, lice, fleas).

The use of the word 'grenade' in the English language apparently originated in the Glorious Revolution (1688), where cricket ball-sized iron spheres packed with gunpowder and fitted with slow-burning wicks were first used against the Jacobites in the battles of Killiecrankie and Glen Shiel.

These grenades were not very effective (probably because a direct hit would be necessary for the grenade to have any effect) and, as a result, they saw little use.

However, trench warfare favored the grenade. In a letter to his sister, Colonel Hugh Robert Hibbert, described an improvised grenade employed during the Crimea War:

We have a new invention to annoy our friends in their pits. It consists in filling empty soda water bottles full of powder, old twisted nails and any other sharp or cutting thing we can find at the time, sticking a bit of tow in for a fuse then lighting it and throwing it quickly into our neighbours pit where it bursts, to their great annoyance. You may imagine their rage at seeing a soda water bottle come tumbling into a hole full of men with a little fuse burning away as proud as a real shell exploding and burying itself into soft parts of the flesh.

In World War I both sides only had small pre-war stocks of grenades so as an interim measure, the troops often improvised their own, such as the Jam Tin Grenade. These were replaced when manufactured versions such as the Mills bomb, the first modern fragmentation grenade, became available to British front-line troops. The Mills bomb was an explosive-filled steel canister with a triggering pin and a distinctive deeply notched surface. This segmentation was thought to aid fragmentation and therefore increase the grenade's deadliness. Later research showed that the segmentation did not improve fragmentation in any way at all. Improved-fragmentation designs would later be made with the notches on the inside, but at the time this would have been too expensive to produce. The external segmentation of the original Mills bomb was retained since it did provide a positive grip surface. This basic "pin-and-pineapple" design is still used in some modern grenades. On the other hand, the U.S. M67 fragmentation grenade has a smooth exterior, which is much more suitable for being rolled into a room or being thrown in a flat arc like a baseball.

To throw grenades further, the rifle grenade was devised. This made use of a modified rifle with a blank cartridge to propel the grenade. These rifles would often be permanently fixed in wooden support frames and would not be used for firing bullets. Also, use was made of catapults, some manufactured, some improvised, although these were eventually replaced in the trenches by small mortars.

Parallel to the Mills bomb and its similar counterparts, the Germans issued the Stielhandgranate, or stick grenade, which featured an explosive charge encased in a metal can and mounted on a wooden shaft for throwing. This simple design continued to evolve throughout the First and Second World Wars, with the Model 24 grenade (popularly known as the "potato masher") becoming one of the most easily recognized of all small arms, and synonymous with the German soldier.

The Molotov cocktail is an improvised grenade prepared from a glass bottle filled with gasoline (petrol) ignited by a burning strip of cloth when the thrown bottle bursts against its target, very similar to the original grenades mentioned at the beginning of this section. The Molotov cocktail was first used by poorly-equipped Finnish Army soldiers against Soviet Union forces during their 1939 Winter War.

Design

Grenades come in different sizes and shapes, for different purposes. Most are designed to explode, projecting shrapnel i.e. sharp pieces of the casing or serrated wire or an incendiary material. Some, like smoke grenades, merely burn, releasing colored smoke for masking, marking or signaling. All grenades have two things in common: First, they are hollow so they can be filled with the explosive or chemical filler. Second, they contain a threaded hole into which a fuse can be screwed or inserted.

A grenade is essentially a small bomb, and works very much like a simple firecracker. A firecracker is made up of a paper body filled with flash powder and fitted with a small fuse. Once lit, the fuse burns down to the powder and blows the paper body apart. In modern hand grenades, the fuse is lit by an internal mechanical, electronic, and/or pyrotechnic device rather than an external flame.

Characteristics

Hand grenades share the following four characteristics:

• Their employment range is short;
• Their effective casualty radius is small;
• Their delay element permits safe throwing;
• Their hard shell, along with their previously mentioned delay element, enables the grenade to ricochet off hard surfaces, like walls, before detonating.

Hand grenades have the following main parts:

• The body contains the filler and, in some grenades, also provides the fragmentation;
• The filler is the chemical or explosive substance in the grenade, which determines the grenade's use and characteristics;
• The fuse assembly causes the grenade to function by igniting or detonating the filler.

Using grenades

A classic hand grenade has a handle (called a spoon) and a removable safety pin that prevents the handle from being released. To use the grenade, the user pulls the pin out of the grenade and throws it, releasing the spoon. Pulling the pin on a grenade requires a large amount of force, so the pin is removed by pulling with a finger rather than with the teeth as is shown in popular motion pictures. Before removing the pin, the soldier grips the grenade to prevent the handle being released at the same time. With the pin removed, the grenade is thrown, the handle is released, and a spring-loaded striker ignites a pyrotechnic delay element in the fuse. The delay burns for two to five seconds, and then activates the detonator, exploding the grenade.

When using an antipersonnel grenade, the objective is to have the grenade explode so that the target is within its effective radius. For the U.S. M67 fragmentation grenade, the effective kill zone has a five meter radius, while the casualty-inducing radius is approximately fifteen meters.

"Cooking off" is a term referring to intentionally holding onto an armed grenade after the pin has been pulled and the spoon released, to lower the number of seconds to detonation before throwing. This technique is used to reduce the ability of the enemy to take cover or throw the grenade back. It is also used to allow the grenade to burst in the air over defensive positions. This technique is inherently dangerous, since fuses vary from grenade to grenade, but its use is necessary in some situations and it is an important technique in combat. Another technique used with grenades is the "bank shot," in which the grenade-thrower throws a grenade at a wall with the intention of having the grenade ricochet off of the wall, taking enemy soldiers by surprise. It is especially effective inside buildings, or in labyrinthine areas. Both cooking off and bank shots are popular techniques not only in the military, but also in multiplayer matches in video games of the first-person shooter genre. A call is usually given upon deploying a grenade to warn friendly forces. Some yells, such as "grenade" are used when a grenade has been thrown in by an enemy; in any instance the purpose is to give notice to fellow soldiers to take cover. When a grenade is dropped into an enclosed space like a tunnel, room, or trench, the person dropping the grenade should yell "fire in the hole" to warn that an explosion is about to occur. A common U.S. Military procedure for the fragmentation grenade, unless stealth is of the essence, is to yell "frag out" to indicate that a fragmentation grenade has been dispatched. Other such calls include "white fire" if a flashbang has been deployed too close, and "bee sting" in a similar case for stingers.

Grenades are often used in the field to construct booby-traps, using some action of the intended target (such as opening a door, or starting an auto) to trigger the grenade. These grenade-based booby-traps are simple to construct in the field using readily available materials. The most basic technique involves wedging a grenade in a tight spot so the spoon does not leave the grenade when the pin is pulled. A string is then tied from the head assembly to another stationary object. When a soldier steps on the string, the grenade is pulled out of the narrow passageway, the spoon flies, and the grenade soon detonates.

Abandoned booby-traps contribute to the increasing problem of unexploded ordnance. The use of tripwire-triggered grenades (along with Claymores and landmines in general) is banned under the Ottawa Treaty and may be treated as a war crime wherever it is ratified. However, China, the United States and the Russian Federation have not signed the treaty despite large international pressures, citing self-defense needs.

Design and operation

The basic action is as follows:

1. Holding the grenade in the throwing hand, thumb over the safety lever, pull the safety pin (pull force of 10–35 pounds or 45–155 newtons).
2. When the grenade is thrown (safety lever released), a spring throws off the safety lever and rotates the striker into the percussion cap.
3. When struck by the striker, it ignites and sets fire to the fuse, or powder train. The fuse burns at a controlled rate, providing a time delay (usually 4–5 seconds). When the flame of the fuse reaches the detonator or igniter, it causes action on the filler.
4. A detonator is similar to a small blasting cap. Very sensitive to heat, when the fuse burns into it, it causes the grenade to explode.
5. An igniter is a cap that burns rapidly. It sets fire to the filler causing a rapidly expanding gas which bursts the container.

Hand grenades are usually designed to make them easy to throw. They weigh around 500 g (1 lb) and have a diameter of 100 mm. Due to the design of grenades left-handed people hold them upside down when thrown. The average grenade can be thrown about 25 to 35 meters by the average soldier. They use a compound of RDX, composition B or TNT as their explosive.

Classical "pineapple" grenades, such as the Mills bomb, used smokeless powder and cast-iron shells, which (in theory) would fragment along deliberately-cast weak points in the shell—although the pattern on the grenade body was actually intended to allow the user to have a firm grip on the grenade. In practice, external grooves in the grenade body turned out to have little or no effect on the size and shape of fragments formed.

Grenades have also been made to release smoke, tear gas ("CS"), and other gases, as well as illumination. Special forces often use "flash-bang" grenades to disorient people during an entry into a room, without the intent of causing lasting injury.

Some grenade designs were made to be thrown longer distances. The German "potato-masher" grenade had a long wooden handle that extended its range by fifty percent. The "potato-masher" was fired by a friction igniter in the head, which was activated by a pull string threaded through the hollow stick. Immediately before throwing the grenade, the soldier pulled a small plastic ring attached to a string attached to the friction igniter. This started the time fuse which fired the detonator after a delay. The "potato-masher" is often incorrectly thought to have had an impact fuse. It did not, but the superficially similar British stick grenade design of 1908 did have such a fuse.

Different types of hand grenades

Fragmentation grenades

The fragmentation grenade (commonly known as a "frag") is an antipersonnel device that is designed to damage or destroy its target with a burst of flying shrapnel. The body is made of hard plastic or steel. Flechettes, notched wire, or the case by itself provide the antipersonnel fragments. The filler may also include small metal balls to injure the target. When the word "grenade" is used without qualification and context does not suggest otherwise, it is generally assumed that a fragmentation grenade is referred to.

These grenades are usually classed as defensive grenades because the effective casualty radius is greater than the distance it can be thrown; it is assumed that they will be thrown from behind cover at attackers. The hand-sized Mills bomb with a cast iron casing is an example of a defensive grenade.

Concussion grenades

The concussion or overpressure grenade is an antipersonnel device that is designed to damage its target with explosive power alone. Compared to fragmentation grenades, the explosive filler is usually of a greater weight and volume. The case is far thinner and is designed to fragment as little as possible. The shock waves overpressure produced by this grenade when used in enclosed areas is greater than those produced by the fragmentation grenade. Therefore, it is especially effective in enclosed areas.

These grenades are usually classed as offensive weapons because the effective casualty radius is smaller than the distance it can be thrown.

The hand-sized US MK3A2 concussion offensive hand grenade is an example of an offensive grenade. It is filled with TNT and has a body made of tarred cardboard. A more famous example of an offensive grenade is the German Model 24 "potato masher" grenade with a standard tin body.

The term concussion is often erroneously applied to stun grenades. This is not descriptive of the effects caused by the grenade. The term concussion is used because the grenade relies only on its explosive power for its casualty-producing effect.

Percussion grenades

The percussion grenade detonates with impact. Timed fuse grenades are usually preferred because it is often useful to have it detonate while it flies above the target, and because percussion grenades could explode while being carried. Some percussion grenades have a slow fuse as a backup ignitor. There have been percussion grenade launchers used in past battles as well.

Smoke grenades

The most common smoke grenades are canister-type grenades. They are used as ground-to-ground or ground-to-air signaling devices, target or landing zone marking devices, and screening devices for unit movements. The body is a sheet-steel cylinder with a few emission holes on top and at the bottom. These allow the smoke to be released when the grenade is ignited. Two main types exist - colored smoke (for signaling) and screening smoke. In colored smoke grenades, the filler consists of 250 to 350 grams of colored smoke mixture (mostly potassium Nitrate, lactose and a dye). Red, green, yellow, and violet smoke grenades are available. Screening smoke grenades usually contains HC (hexachloroethane/zinc) smoke mixture or TA (terephthalic acid) smoke mixture. HC smoke is harmful to breathe, since it contains hydrochloric acid.

A second type of smoke grenade is the explosive bursting type. These are filled with white phosphorus (WP). Rather than igniting a mixture which burns to make smoke, the WP grenade contains a bursting charge which spreads the white phosphorus by explosive action. White phosphorus catches fire in the presence of air, and burns with a brilliant yellow flame, producing copious amounts of dense white smoke (phosphorus pentoxide). These grenades also function as incendiary and antipersonnel weapons. Newer types of bursting smoke grenades are filled with titanium tetrachloride, which has no incendiary action.

Riot control

Contrary to popular belief, gas-expelling grenades are rarely used to disperse large groups, because of the risk of causing generalized panic. Grenades are instead used to create barriers of tear gas in order to direct the movement of large groups of people, or to protect police officers on the verge of being overwhelmed. As an exception, tear gas may be used to disperse a mob surrounding a small centralized group of victims.

Similarly, gas-expelling grenades are not often used to force criminals out of their cover because of the risk of intoxicating people in enclosed areas, although SWAT teams will occasionally employ CS gas grenades to facilitate the arrest of an armed suspect, especially if there are no bystanders in the area. This kind of deployment is used most often in an area where several suspects have a large amount of cover, since the functioning of other distraction grenades will be hindered.

Tear gas grenades are similar to burning smoke grenades in terms of shape and operation. However in tear gas grenades the filler is 80 to 120 grams of CS gas (chlorobenzylidene malononitrile). This chemical causes an extreme burning sensation in the eyes and—when inhaled—in the throat. (See also the Branch Davidian siege and riot control agents.)

Incendiary grenades

Incendiary grenades produce intense heat by means of a chemical reaction. The body is practically the same as that a smoke grenade. The filler is 600 to 800 grams of thermate (TH3), which is an improved version of the World War II-era thermite. The chemical reaction that produces the heat is called a "thermite reaction." In this reaction, aluminum metal and iron oxide (rust) react to produce iron and aluminum oxide. This reaction produces a tremendous amount of heat, burning at 2200 degrees Celsius (4000 degrees Fahrenheit). A thermite grenade can melt together the metallic parts of an object. This makes incendiary grenades such as the AN-M14 useful for destroying weapons caches, artillery units, and vehicles. Other advantages of thermate include its ability to burn through a 1/2-inch (12,7 mm) steel plate, and that an external oxygen source is not needed to sustain the reaction. Because of this, an AN-M14 can burn underwater.

White phosphorus (also used in smoke grenades; see above) can also be used as an incendiary agent. It burns at a temperature of 2800 °C (5000 °F).

Thermite and white phosphorus cause some of the worst and most painful burn injuries because they burn so quickly and at such a high temperature. A single lit particle can burn through skin, nerves, muscles and even bones. In addition, white phosphorus is very poisonous: a dose of 50-100 milligrams is lethal to the average human.

Stun grenades

Stun grenades, also known as flashbangs, were originally designed for the British Special Air Service. Stun grenades are used to confuse, disorient, or momentarily distract a potential threat for up to five seconds. A "flashbang" can seriously degrade the combat effectiveness of affected personnel for up to a minute. The best known is the M84 Stun Grenade, commonly known as the "Flashbang", so called because it produces a blinding (1 million Candela) flash and deafening (170-180 decibel) blast. This grenade can be used to incapacitate people, generally without causing serious injury. Standard operating procedure for LAPD SWAT has officers deploy flashbangs close to the point of entry. This is because all attention will be directed towards the door once it has been breached, and deploying the flashbang close to this point heightens the chances that a suspect will be affected by the device.

The physiological processes through which this is made possible are quite simple. The flash of light momentarily activates all photosensitive cells in the retina, making vision impossible for approximately five seconds until the eye restores the retina to its original, unstimulated state. Subjects affected by flashbangs describe seeing a single frame for the five seconds (as if their vision was "paused") until it fades and normal sight returns. This is because the sensory cells which have been activated continue sending the same information to the brain until they are restored to their resting state, and the brain translates this continuous information into the same image. The incredibly loud blast emitted from the grenade contributes to its incapacitative properties by disturbing the fluid in the semicircular canals of the ear. The semicircular canals consist of three half circles of tubing, each oriented in one of the three planes of motion, that are filled with saline. The walls of the tubes are lined with hair cells which use their small, hairlike cilia to detect the motion of the water. This establishes a person's sense of balance and movement through space. When a flashbang detonates, the water in the semicircular canals is disturbed, and with it the subject's sense of balance. The phenomenon is similar to spinning rapidly in one direction, and suddenly stopping. The sensation that the room is moving comes from the movement of the water in the inner ear.

Upon detonation, the fuse/grenade body assembly remains intact and produces no fragmentation. The body is a steel hexagonal tube with holes along the sides which allow a blast of light and sound to be emitted. This is done to prevent injury from shrapnel. However, injuries resulting from the concussive properties of the detonation sometimes occur. The filler consists of about 4.5 grams of a pyrotechnic metal-oxidant mix of magnesium and ammonium perchlorate.

Sting grenades

Sting grenades, or Hornet's Nest grenades, are another less-lethal grenade that is based on the design of a fragmentation grenade. Instead of using a metal casing to produce shrapnel, however, they are made using two spheres of hard rubber. Inside the smaller sphere is the explosive charge, primer, and detonation pin. The space between the two spheres is then filled with many small, hard rubber balls about 20mm in diameter. Upon detonation, the subject is incapacitated by the blunt force of the projectiles. The advantage to using sting grenades comes from the fact that the subject is very often knocked out, winded, or at the very least dislodged from cover because of the shock. Vision is sometimes also impaired due to minor trauma of the visual cortex located in the back of the head.

Some types have an additional payload of chemical agents like CS gas or pepper spray.

The advantages compared to a flashbang are

• The "plug 'n shut" tactic, which is shutting one's eyes and plugging one's ears to avoid being affected by a flashbang. This does nothing to protect a person from a Hornet's Nest's payload,
• The recipient does not need to be looking at the grenade for it to take its full effect,
• Stingers are much more likely to cause a subject to either fall or lower himself in pain, thus providing good sight lines to unaffected targets in the area

This makes sting grenades ideal for containing small groups of rowdy prisoners, providing a shooting opportunity when a suspect is hiding behind cover, or in allowing SWAT teams to clear small rooms. In many situations, it is preferable to a flashbang.

A disadvantage of using sting grenades is that a sting grenade is not sure to lessen the lethality of a suspect, so it is dangerous to use if the subject is armed. This arises from the fact that sting grenades rely on the body's reaction to adversive stimuli (pain and blunt force trauma) rather than in denial of sensory input. A person with sufficient mental focus can concentrate enough to fire a few shots even after being hit by a sting grenade's payload, whereas a flashbang will physically affect vision and sense of orientation in space.

Also, the effective range of a sting grenade is limited compared to a flashbang.

Impact stun grenades - Blank Firing Impact Grenade or BFIG

A more recent development is the Blank Firing Grenade (BFIG or Blank Firing Impact Grenade). Preferred in many situations, especially training, for two main reasons; they are re-usable - and therefore more economical - because the charge is a standard ammunition blank, and they are subject to very few transport restrictions when unloaded. The BFIG contains a mechanism to fire a blank cartridge when dropped at any angle onto a hard surface from a height of a metre or more. Firing will occur in any combination of positions only on impact.

Anti-tank grenades

The first anti-tank grenades were improvised devices usually made by putting a number of fragmentation grenades into a sandbag or by tying them together. Due to their weight, these were normally thrown from very close range or directly placed in vulnerable spots onto an enemy vehicle.

Purpose-designed anti-tank grenades invariably use the shaped charge principle to penetrate the tank's armour. This means that the grenade has to hit the vehicle at an exact right angle for the effect to work properly. This is achieved by the grenade deploying a small drogue parachute or fabric streamers after being thrown.

The British put the first anti-tank grenade into the field during the Second World War with the rifle-fired No 68 AT Grenade. Also developed by the British during the Second World War, was the No 74 ST Grenade popularly known as a sticky bomb; the main charge was held in a sphere covered in adhesive. In anticipation of a German invasion, it was produced in substantial numbers. Inherently dangerous for the user it was relegated to Home Guard use.

The most widely-distributed anti-tank grenades are the Russian designs of the 1950s and later, mainly the RKG-3.

Due to improvements in modern tank armor, anti-tank grenades are nowadays generally considered obsolete.

Grenades as ornamentation

Stylized pictures of early grenades, with a flame coming out, are used as ornaments on military uniforms, particularly in France (esp. French Gendarmerie) and Italy (Carabinieri). The British Grenadier Guards took their name and cap badge of a burning grenade from repelling an attack of French Grenadiers at Waterloo.

Etymology

The word "grenade" originally meant the pomegranate fruit, and was transferred to early explosive grenades whose filling was gunpowder with many small pieces of metal embedded in it.

See also

• Nils Waltersen Aasen, the creator of the modern hand grenade.
• The grenade is also a charge in heraldry.
• Grenade is also the name of a commune in the Haute-Garonne département, in France.
• Holy Hand Grenade of Antioch

External links

• Film of exploding grenade - taken using ultra high-speed photographic technique (2/3 million frames per second)
• How Grenades Work - from HowStuffWorks

References

1. Cramb, Auslan (2004). "Battlefield gives up 1689 hand grenade". Scotland Correspondent. {{cite journal}}: Unknown parameter |month= ignored (help)
2. "The National Archives, records of the UK government". Letters of Hibbert, Hugh Robert, 1828-1895, Colonel, ref. DHB/57 - date: 14 Jun. 1855. Retrieved 2006-08-09.
3. United States Army Field Manual 3-23.30, Grenades and Pyrotechnic Signals (2005 revision), page 1-6
4. United States Army Field Manual 3-23.30, Grenades and Pyrotechnic Signals (2005 revision), pages 3-11 to 3-12
5. Hogg, Ian. The Encyclopedia of Infantry Weapons of World War II. Northbrook, IL: Book Value International. p. 159. ISBN 0-89196-099-6.
6. Hand Grenades from Nammo AS

• Less-lethal weapons
• Grenades
• Incendiary weapons