Using Grenades
A classic hand grenade has a safety handle or lever (known in the US forces as the spoon,) and a removable safety pin that prevents the handle from being released. Some grenade types also have a safety clip to further prevent the handle from coming off in transit.
To use a grenade, the soldier grips it with the throwing hand, ensuring that his thumb holds the safety lever in place. Left-handed soldiers are advised to invert the grenade, so the thumb is still the digit that holds the safety lever. The soldier then grabs the safety pin's pull ring with the index or middle finger of the other hand and removes it. He then throws the grenade towards the target. Soldiers are trained to throw grenades in standing, prone-to-standing, kneeling, prone-to-kneeling, and alternate prone positions and in under- or side-arm throws. If the grenade is thrown from a standing position the thrower must then immediately seek cover or lie prone if no cover is nearby.
Once the soldier throws the grenade, the safety lever releases, the striker throws the safety lever away from the grenade body as it rotates to detonate the primer. The primer explodes and ignites the fuse (sometimes called the delay element). The fuse burns down to the detonator, which explodes the main charge.
When using an antipersonnel grenade, the objective is to have the grenade explode so that the target is within its effective radius. The M67 frag gren has an advertised effective kill zone of five meter radius, while the casualty-inducing radius is approximately fifteen meters. Fragments can fly as far as 230 meters. Usually people in a 15 meter radius are injured enough to effectively render them harmless.
Cooking off is a term referring to intentionally holding onto an armed grenade after the pin has been pulled and the handle released; allowing the fuse to burn partially to decrease the time to detonation after 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 may vary from grenade to grenade. Because of this the U.S. Marines (MCWP 3-35) describe cooking-off as the "least preferred technique," recommending a "hard throw, skip/bounce technique" to prevent an enemy returning a grenade.
A call is usually given upon deploying a grenade, to warn friendly forces. Some yells, such as frag out or fire in the hole, signal that a grenade has been deployed. In any instance the purpose is to warn fellow soldiers to take cover. In the U.S.M.C. when a grenade is dropped into an enclosed space like a tunnel, room, or trench, the person dropping the grenade yells fire in the hole to warn that an explosion is about to occur. U.S. military procedure includes calling frag out to indicate that a fragmentation grenade has been deployed.
Grenades have often used in the field to construct booby traps, using some action of the intended target (such as opening a door, or starting a car) to trigger the grenade. These grenade-based booby traps are simple to construct in the field as long as instant fuzes are available, a delay in detonation can allow the intended target to take cover. The most basic technique involves wedging a grenade in a tight spot so the safety lever 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 safety lever is released, and the grenade detonates.
Abandoned booby traps and discarded grenades contribute to the problem of UXO. The use of target triggered grenades and AP mines is banned to the signatories of the Ottawa Treaty and may be treated as a war crime wherever it is ratified. Many countries including India, the People's Republic of China, Russia, and the United States have not signed the treaty citing self-defense needs.
Grenades have also been made to release smoke, tear gas and other gases, as well as illumination. stun grenades are often used to disorient people during entry into a room, especially where hostages or non-combatants may be present.
Some grenades are designed 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, activated by a pull string threaded through the hollow handle. Immediately before throwing the grenade, the soldier pulled a small porcelain ball at the end of 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.
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