The M84 is the currently-issued

stun grenade A stun grenade, also known as a flash grenade, flashbang, thunderflash, or sound bomb, is a less-lethal explosive device used to temporarily disorient an enemy's senses. Upon detonation, they produce a blinding flash of light and an extremely lo ...

("flashbang") of the

United States Armed Forces The United States Armed Forces are the military forces of the United States. The armed forces consists of six service branches: the Army, Marine Corps, Navy, Air Force, Space Force, and Coast Guard. The president of the United States is ...

and SWAT teams throughout the United States. Upon detonation, it emits an intensely loud "bang" of 170–180 decibels and a blinding flash of more than one million

candela The candela ( or ; symbol: cd) is the unit of luminous intensity in the International System of Units (SI). It measures luminous power per unit solid angle emitted by a light source in a particular direction. Luminous intensity is analogous t ...

within of initiation, sufficient to cause immediate

flash blindness Flash blindness is an either temporary or permanent visual impairment during and following exposure of a varying length of time to a light flash of extremely high intensity, such as a nuclear explosion, flash photograph, lightning strike, or extre ...

deafness Deafness has varying definitions in cultural and medical contexts. In medical contexts, the meaning of deafness is hearing loss that precludes a person from understanding spoken language, an audiological condition. In this context it is written ...

tinnitus Tinnitus is the perception of sound when no corresponding external sound is present. Nearly everyone experiences a faint "normal tinnitus" in a completely quiet room; but it is of concern only if it is bothersome, interferes with normal hearin ...

, and inner ear disturbance.U.S. Army’s Search for an Economical Device for Stun Hand Grenade Training
" (PDF). dtic.mil, pg. 5. Retrieved on 24 July 2009. Exposed personnel experience disorientation, confusion and loss of coordination and balance. While these effects are all intended to be temporary, there is risk of permanent injury. Consequently, the M84 is classified as a

less-lethal weapon Non-lethal weapons, also called nonlethal weapons, less-lethal weapons, less-than-lethal weapons, non-deadly weapons, compliance weapons, or pain-inducing weapons are weapons intended to be less likely to kill a living target than conventiona ...

.FM 3-23.30 "Grenades and Pyrotechnic Signals
. globalsecurity.org, 1 September 2000. Ch. 1, Sec. 10. "Stun Hand Grenades". Retrieved on 24 July 2009.
. pica.army.mil. Retrieved on 24 July 2009.

Design

The M84 features a

magnesium Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ta ...

-based

pyrotechnic Pyrotechnics is the science and craft of creating such things as fireworks, safety matches, oxygen candles, explosive bolts and other fasteners, parts of automotive airbags, as well as gas-pressure blasting in mining, quarrying, and demolition. ...

charge inside a thin aluminum case, contained within a perforated

cast steel Steel casting is a specialized form of casting involving various types of steel cast to either final/net or near-net shape. Steel castings are used when iron castings cannot deliver enough strength or shock resistance.Oberg, p. 1332 Examples ...

body. Unlike the

high explosives An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An expl ...

(HE) used in traditional ordnance, the pyrotechnic charge produces a subsonic deflagration, not a supersonic

detonation Detonation () is a type of combustion involving a supersonic exothermic front accelerating through a medium that eventually drives a shock front propagating directly in front of it. Detonations propagate supersonically through shock waves with s ...

, minimizing the blast effects. On initiation the auditory and visual elements of the deflagration being permitted to escape via the perforations in the cast outer body. This design minimizes the risk of collateral damage due to flame, blast and unconsumed fragments of the inner case. It is intended to be thrown into enclosed spaces to distract and temporarily incapacitate enemy personnel for easier capture, or when risk of

collateral damage Collateral damage is any death, injury, or other damage inflicted that is an incidental result of an activity. Originally coined by military operations, it is now also used in non-military contexts. Since the development of precision guided ...

during

urban warfare Urban warfare is combat conducted in urban areas such as towns and cities. Urban combat differs from combat in the open at both the operational and the tactical levels. Complicating factors in urban warfare include the presence of civilians a ...

hostage rescue A hostage is a person seized by an abductor in order to compel another party, one which places a high value on the liberty, well-being and safety of the person seized, such as a relative, employer, law enforcement or government to act, or refr ...

operations contravenes the employment of traditionally lethal and destructive fragmenting high explosive ordnance.

US Army The United States Army (USA) is the land service branch of the United States Armed Forces. It is one of the eight U.S. uniformed services, and is designated as the Army of the United States in the U.S. Constitution.Article II, section 2, cla ...

doctrine calls for the M84 to be deployed "during building and room clearing operations, when the presence of

noncombatant Non-combatant is a term of art in the law of war and international humanitarian law to refer to civilians who are not taking a direct part in hostilities; persons, such as combat medics and military chaplains, who are members of the belligerent a ...

s is likely or expected and the assault element is attempting to achieve surprise." While the M84 is generally incapable of igniting paper or cloth, it can still ignite extremely flammable liquids or vapors (such as concentrated

gasoline Gasoline (; ) or petrol (; ) (see ) is a transparent, petroleum-derived flammable liquid that is used primarily as a fuel in most spark-ignited internal combustion engines (also known as petrol engines). It consists mostly of organi ...

ether In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom connected to two alkyl or aryl groups. They have the general formula , where R and R′ represent the alkyl or aryl groups. Ethers can again be ...

fumes) in the immediate area of the grenade.M84 Stun Grenade
. globalsecurity.org, 10 January 2006. Retrieved on 24 July 2009.

References

{{Use dmy dates, date=June 2017 Stun grenades Hand grenades of the United States Military equipment introduced in the 1990s

Design

See also

References