United States 40 Mm Grenades

The United States Armed Forces has created a plethora of different types of 40 mm grenades in both the low-velocity 40×46 mm and high-velocity 40×53 mm calibers which uses what it calls a '' high-low propulsion system'' which keeps recoil forces within the boundaries of an infantry weapon. Presented on this page is a basic overview.

High-explosive cartridges

Standard high-explosive cartridges

High explosive grenades were one of the first rounds created for the 40×46 mm and 40×53 mm calibers, and while basic HE grenades have largely been replaced by more complex multi-purpose ones, they are nonetheless an important part of their development.

40×46 mm types include the ''M381'', ''M386'', ''M406'', and ''M441''. The ''M386''/''M406'' differ from the ''M381''/''M441'' in that they have longer arming distances (14–28 meters compared to the 2–3 meters of the ''M381'' and ''M441'').

40x53 mm types include the ''M383'' (and the ''M383E1'') and the ''M384''.

Other high-explosive cartridges

HE grenades have been considered the standard for both types of 40 mm grenades, but over the years the functions of the weapons using these grenades has dramatically expanded, and as a result the need to be able to engage larger and more armored targets.

40×46 mm types include the ''M397A1'', ''M433'', ''M463'', and the newer ''M1060''.

The ''M397'' is a pre-set airburst munition, designed to allow grenadiers to engage targets in trenches and behind cover. It features a bounding charge that is detonated by ground impact.

The ''M433'' HEDP (high explosive, dual purpose), standardized in 1971, has largely become the standard with its ability to effectively engage light vehicles and personnel. The ''M433'' combines a small shaped charge with a wire fragmentation mesh for the dual effect.Cooke, Gary W. 14 February 2008. ''Gary's Olive Drab Page''.
40mm Low-Velocity Grenades
Access Date: 20 March 2008

The ''M463'' is a specialist type developed during the Vietnam War by AAI, and is smokeless and flashless (SF), and uses a type of piston system to force the grenade out of the cartridge, but keep the propellant and gases contained. While this does reduce the effective range of the projectile, it allows for an almost silent 40 mm HE grenade.

The ''M1060'' is a thermobaric cartridge, designed to destroy targets through a combination of intense heat and forceful overpressure (concussion). The ''M1060'' was developed in order to give grenade launchers a far greater effect against static targets such as bunkers, houses, and masonry.

The ''M430'' and ''M430A1'' are 40×53 mm HEDP cartridges akin to the low-velocity ''M433''. They differ in how much armor they can penetrate, with the ''M430'' being able to penetrate 51 mm of steel plate, and the ''M430A1'' being able to penetrate 76 mm.

The replacement HEDP ''XM1176'' is a high-explosive dual purpose grenade designed to be fired by automatic grenade launchers, like the Mk19.

The grenade can be set to explode on impact. It can penetrate the steel plate of lightly armored vehicles. Alternately, it can be programmed to explode in an air burst. An intelligent aiming system calculates the range the operator's target. When the operator finishes pulling the trigger, the range at which the munition should explode is downloaded to the projectile.

Also produced was a special 40×53 mm airburst munition for use with either the M75 or M129 automatic grenade launchers, commonly used from helicopters. This round was designated ''M684''.

Anti-personnel cartridges

When 40 mm grenade launchers were first developed, the weapon was to be the primary weapon of the infantryman carrying it. It was quickly found that in most engagements, while the grenadier gave the squad a decided force multiplier, they were also decidedly exposed if presented with an enemy within the arming distance of most high explosive rounds. Rounds with shorter arming distances presented significant danger to the shooters if used at those ranges. Prior to development of grenade launchers attached to standard infantry rifles, development commenced on non-explosive cartridges to allow those armed with grenade launchers to engage targets at shorter ranges safely.

Similar rounds have also been developed for weapons chambering the higher velocity 40x53 mm cartridge as well.

These anti-personnel rounds fall primarily into what is considered the "canister" category.

40×46 mm types include the '' M576'' series.

The ''M576'' contains twenty 20-grain (1.30-gram) metal pellets. The ''XM576''/''XM576E1'' was standardized to become the ''M576''. Another test variant, the ''XM576E2'', which had twenty-seven 20-grain (1.30-gram) metal pellets without a sabot within the shot cup, was deemed to spread too quickly for effective use.

The only current 40×53 mm type is the ''M1001'', a canister round filled with one-hundred and fifteen 17-grain 2.0-inch long flechettes. During the late 1960s, Nortronics was developing the ''XM678''. References have listed different projectile loads ranging from thirty-two 0.24 inch carbide pellets up to fifty-four 30 grain (1.94 gram) tungsten pellets.

Smoke, signaling, and illumination cartridges

Smoke cartridges

The most numerous of the 40×46 mm grenades, smoke rounds can be launched further than normal smoke hand grenades can be thrown, and come in numerous colors. These grenades are used for both signaling and obscuration, and come in two main types, "canopy" and "ground marker".

40×46 mm canopy smoke grenades come in three colors: yellow (''M676''), white (''M680''), and red (''M682''). These were developed to penetrate dense canopy foliage in order to mark or signal a position.

Ground markers also come in three colors: red (''M713''), green (''M715''), and yellow (''M716'').

In development are new marking cartridges designed to improve the already considerable night-fighting capabilities of US forces. The ''XM1062'' and ''XM1065'' operate like conventional ground markers, but the ''XM1062'' marks in the IR spectrum, while the ''XM1065'' shows up on thermal imaging devices.

Older cartridges designed specifically for the M79 grenade launcher or the AN/M8 pyrotechnic pistol also remain in inventory. The ''XM675''/''M675'' is a red smoke cartridge used primarily for training in the use of the ''XM674''/''M674'' riot control cartridge.

A 40×53 mm white phosphorus cartridge, designated ''XM574'', was developed, but not standardized. Intended for use in the UH-1B Iroquois helicopter using the M5 Armament Subsystem, the round was not adopted because of safety concerns. Testing during 1966 concluded that there were significant reliability issues, as well as, potential environmental concerns (detonation or malfunction from high temperatures and humidity in the South East Asian theater) and increased vulnerability (the WP filler was dangerous if struck by small arms fire).

Signalling and illumination cartridges

Unlike conventional hand grenades, a personal grenade launcher can easily be used to launch flares as a signaling or illumination device. Like 40 mm smoke grenades in the US military, they are all of 40×46 mm caliber, serving more of a use in an individual rather than a crew-served capacity. They also come in two main types, cluster flares and parachute flares. Cluster flares are used primarily for signaling, while parachute flares are used primarily for illumination.

40×46 mm cluster flares come in three colors: white (''M585''), green (''M663''), and red (''M664''). Individual flares burn for seven seconds after ignition. The ''M585'' is the standardization of the ''XM585E1''. The differences between it and the ''XM585'' are unclear.

Parachute flares come in four colors: white (''M583/A1''), green (''M661''), red (''M662''), and orange (''XM695''). The parachute is designed to create a seven-feet-per-second descent, while the flare itself has a 40-second burn time. The XM695 was never standardized.

Also, because of the development in the United States military of complex night-fighting tactics, an illumination cartridge for use with night vision equipment, that illuminates in the infrared spectrum was also developed.

The infra-red illumination cartridge (IRIC) ''M992'' is a 40 mm low pressure grenade, designed to be fired from man-portable grenade launchers, to provide infrared illumination.

The grenade is designed to be fired into the air. When it gets to its maximum height it deploys a small parachute, and ignites an infrared pyrotechnic flare. The flare is designed to only provide useful illumination to people wearing night-vision googles. The flare will burn for at least 40 seconds.

If fired directly overhead it can reach an altitude of to . The parachute slows its descent to per second

The similar '' M583A1'' is fired the same way, but illuminates in visible light.

Less-lethal and riot-control cartridges

With the greater emphasis on improving less-lethal capabilities of the U.S. military in response to the changing nature of U.S. deployments around the world, less-lethal and riot control cartridges have been developed over the years. These rounds are often akin to 37 mm cartridges that have been in use by law enforcement for years. These cartridges are also mainly 40×46 mm.

Oldest of these types is the riot control 40 mm gas cartridge. In the U.S. military the standard CS gas cartridge is designated ''M651''. The ''M651'' has 53 grams of CS mixture. Burn time is 25 seconds, with coverage of 120 square meters. The round is effective to 200 meters against point targets and 400 meters against area targets. It is unclear which of the experimental variants, either the ''XM651'' or ''XM651E1'' was standardized.

Older cartridges designed specifically for the M79 grenade launcher or the AN/M8 pyrotechnic pistol also remain in inventory. The ''XM674''/''M674'' is a CS riot control agent cartridge. The unit contains 90-100 grams of CS mixture, with a 2-7 second ignition delay and burn time of 10 to 40 seconds. The round is effective to a distance of 65 to 90 meters. It can also be hand fired.United States, 1983. p. 27; United States, 1996. p. 105

More recent have been a variety of canister rounds and other less-lethal projectiles. The ''M1029'' contains 48 rubber balls of .48 inch diameter. The ''M1029'' is still considered to be potentially lethal under 10 meters and ineffective at distances over 30 meters.

The ''M1006'' launches a solid foam "sponge grenade" at high enough velocity to wind someone or in extreme cases perhaps even break bones. The use of a softer foam sponge in the ''M1006'' is likely a product of the serious injuries and fatalities caused by rubber and plastic batons in use by police forces around the world over the last few decades. The ''M1006'' is still potentially lethal when fired at distances under 10 meters, having an 81-meter per second muzzle velocity, and is largely ineffective at distances over 50 meters.

Unique and specialist cartridges

The ''XM688'' cartridge was designed as a sort of giant grenade launching cartridge. It was supposed to be coupled with the grapnel, launcher propelled, ''XM1'' and the '' M79''. The resulting combination allowed users to launch a hook over a greater distance than if it had been thrown, thus allowing them to scale to higher places. Similar systems had been developed independently, and had been used during the landings at Normandy during the Second World War at Pointe du Hoc, but the ''XM688'' allowed an existing infantry weapon to be used in this capacity.

Green ammunition

The '' MK281'' is a new type of 40 mm grenade ammunition that has been accepted for use into the United States Marine Corps and the United States Army. The Rheinmetall ''MK281'' Mod 0 and Mod 1 40×53 mm practice cartridges are precision, high-velocity training and practice cartridges. The ''MK281'' uses a patented Rheinmetall propulsion unit that is designed to produce a very low standard deviation in muzzle velocity for improved accuracy. The ''MK281'' round is compatible with all types of automatic grenade launchers, including the ''MK19'', the ''MK47'' and the HK GMG, and comes in two different types: 40×53 mm cartridge ''MK281'' Mod0 impact marker and 40×5 3mm cartridge ''MK281'' Mod1 day-night marker. The ''MK281'' is manufactured by an American subsidiary of the Rheinmetall Group. The Mod1 cartridge allows operators to train at night; the cartridge marking is visible to both the naked eye and when using night vision equipment. As an additional option, a tracer is available for both variants of the cartridge. This tracer has a burn time of six seconds and allows the user to observe the ammunition’s trajectory as it approaches the target.

See also

* 35 mm grenade
* List of individual weapons of the U.S. Armed Forces
* List of vehicles of the U.S. Armed Forces

References

Citations

Sources

* United States, US Army, Army Concept Team in Vietnam. ''Final Report of the Cartridge, 40mm, WP, XM-574''. Saigon, Vietnam: Army Concept Team in Vietnam, 1966.
* United States, US Army, Armament Research and Development Command, Chemical Systems Laboratory. ''Civil Disturbance Countermeasures - Chemical''. Aberdeen Proving Ground, MD: Armament Research and Development Command, Chemical Systems Laboratory, 1983.
* United States, US Marine Corps. ''MCRP 3-37C Flame, Riot Control Agents and Herbicide Operations''. Washington, DC: US Marine Corps, 1996.
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External links

Gary's Green Olive Grenade Page



Grenades of the United States
40 mm artillery