Survey of modern US 40 mm grenades
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The United States Army has created a plethora of different types of 40 mm grenades in both the low velocity 40x46 mm and high velocity 40x53 mm calibers. Presented on this page is a basic overview.
This is a work in progress, and some grenades may in the future warrant a specific entry dedicated to them.
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[edit] High Explosive Cartridges
[edit] Standard High Explosive Cartridges
High explosive grenades were probably the first rounds created for the 40x46 mm and 40x53 mm calibers, and while basic HE grenades have largely been replaced by more complex multi-purpose ones, they are none the less an important part of the development of the type.
40x46 mm types include the M381, M386, and M441. The M441 can be seen as a developmental improvement over the M381, probably with an improved filler and/or fuze mechanism. The M386 differed from the M381/M441 in that it had a longer arming distance (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. Most likely the differences are similar to their low velocity cousins, and have something to do with the reliability and safety improvements made over time.
[edit] Other High Explosive Cartridges
HE grenades may well be 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.
40x46 mm types include the M397A1, M406, M433, M463, and the new M1060. The M397 was a pre-set airburst munition, designed to allow grenadiers to engage targets in trenchs and behind cover. The M406 had an armor piercing core for better effect against light armor, and the M433 HEDP (High Explosive, Dual Purpose) has largely become the standard with its ability to effectively engage light vehicles and personnel.
The M463 was a specialist type developed during the conflict in Vietnam by AAI, and was "SF" or Smokeless/Flashless, and used a type of pistol system to force the grenade out of the cartridge, but keep the propellant and gasses contained. While this did reduce the effective range of the projectile it did allow for an almost silent 40 mm HE grenade.
The M1060 is a thermobaric cartridge, which means it is designed to destroy targets through a combination of intense heat and forceful overpressure (better known as "concussion"). The M1060 was developed in order to give personnel grenade launchers a far greater effect against static targets such as bunkers, houses, and masonry.
The M430A1 is a 40x53mm HEDP cartridge akin to the low velocity M433. Also produced was a special 40x53mm airburst munition for usage from either the M75 of M129 automatic grenade launchers, commonly used on helicopters. This round was designated M684.
[edit] 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. Even rounds with a shorter arming distance presented significant danger to the shooter if used at those ranges. Prior to development of grenade launchers attached to standard infantry rifles (though this was also done in the field by members of the US military in Vietnam, if on a very ad hoc basis), development commenced on non-explosive cartridges to allow those armed with 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, probably in response to the desire by soldiers for such ammo in ambush or similarly short range engagements.
These anti-personnel rounds fall primarily into what could be considered the "canister" category, and are designed in most cases to turn the grenade launcher into what many would think of as a large shotgun.
40x46 mm types include the M576 and the XM678. The M576 contains 20 pellets of #4 buckshot for shotguns. The XM576/XM576E1 was standardized to become the M576. Another test variant, the XM576E2, which had 27 pellets of #4 buckshot without a sabot within the shot cup was deemed to spread too quickly for effective use. The XM678 does not appear to have been standardized and contained 54 tungsten balls, again of unknown size and weight, but likely considerably smaller than those in the M576 if number of projectiles is any gauge.
The only 40x53 mm type to exist is the M1001 and is a canister round filled with 115 17-grain 2.0-inch long flechettes. The choice of fin-stabilized flechettes over pellets or similar projectiles for the high velocity ammo is most likely a product of their greater accuracy over slightly longer ranges.
[edit] Smoke, Signalling, and Illumination Cartridges
[edit] Smoke Cartridges
Most numerous of 40x46 mm grenades, and not surprisingly so, smoke grenades that can be launched further than normal smoke hand grenades also come in numerous colors. These grenades are used for both signalling and obscuration, and come in two main types, "canopy" and "ground marker."
40x46 mm canopy smoke grenades come in 3 colors: yellow (M676), white (M680), and red (M682). Ground markers also come in 3 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's marks in the IR spectrum, while the XM1065 shows up on thermal imaging devices.
Older cartridges designed specifically for the M79 or the AN/M8 launchers also remain in inventory. The XM675/M675 is a red smoke cartridge.
40x53 mm cartridges of this type are not known to be in use by the US military.
[edit] Signalling and Illumination Cartridges
Unlike conventional hand grenades, a personal grenade launcher can easily be used to launch flares as a signalling or illumination device. Like 40 mm smoke grenades, in the US military they are all of 40x46 mm caliber, serving more of a use in the individual capacity rather than the crew-served capacity. They also come in two main types, cluster flares and parachute flares. Cluster flares are used primarily for signalling, while parachute flares are used primarily for illumination.
40x46 mm cluster flares come in 3 colors: white (M585), green (M663), and red (M664). Parachute flares come in 4 colors: white (M583/A1), green (M661), red (M662), and orange (XM695). The XM695 was never standardized.
Also, because of the development in the United States military of complex nightfighting tactics, an illumination cartridge for use with night vision equipment, that illuminates in the infrared spectrum was also developed. This Infra-Red Illumination Cartridge (or IRIC) was designated XM992/M992.
[edit] Less than Lethal and Riot Control Cartridges
With the greater emphasis on improving less than lethal capabilities of the US military in response to the changing nature of US deployments around the world, less than 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 the Law Enforcement community for years. These cartridges are also mainly 40x46 mm, as it is likely that a high velocity variant of any would greatly detract from their less-than-lethal capabilities.
Oldest of these types is the riot control 40 mm gas cartridges that exist. In the US military the standard CS gas cartridge is designated M651. It is unclear which of the experimental variants, either the XM651 or XM651E1 was standardized, but the differences most likely have to do with the nature of the agent or the type of agent (though the evidence is relatively clear that CN was never used in the XM651). Older cartridges designed specifically for the M79 or the AN/M8 launchers also remain in inventory. The XM674/M674 is a CS riot control agent cartridge.
More recent have been a variety of canister rounds and other less-than-lethal projectiles. The M1029 contains 48 rubber balls of .48" diameter, while the M1006 launches a solid foam "sponge grenade" at high enough velocity to wind someone or in extreme cases perhaps even break bones. However, 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 30 years or so.
[edit] Unique and Specialist Cartridges
The XM688 cartridge does not really fit into any of the above categories. Designed as a sort of giant grenade launching cartridge, the XM688 was supposed to be coupled with the Grapnel, Launcher Propelled, XM1 and the M79. The resulting combination allowed the user to launch the hook over a greater distance than if it had been hand thrown, thus allowing them to scale 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. The actual combat applications of such a "weapon" must be relatively limited.
[edit] See also
- List of individual weapons of the U.S. Armed Forces
- 40 mm grenade
- List of vehicles of the U.S. Armed Forces
