United States 40 mm grenades The United States Army has created a plethora of different types of 40 mm grenade s in both the low velocity 40×46 mm and high velocity 40×53 mm calibers which uses what it calls High - Low Propulsion System which keeps recoil forces within the boundaries of 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were one of the first rounds created for the 40×46mm and 40×53mm calibers , and while basic HE grenades have largely been replaced by more complex multi - purpose ones , they are nonetheless an important part of their development . 40×46mm types include the M381 , M386 , M406 , and M441 . The M386 / M406 differed from the M381 / M441 in that they had a longer arming distance ( 14 – 28 meters compared to the 2 – 3 meters of the M381 and M441 ) . 40x53mm 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 new M1060 . The M397 was a pre - set airburst munition , designed to allow grenadiers to engage targets in trenches and behind cover . It featured a bounding charge that was 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 . The M463 was a specialist type developed during the Vietnam War by AAI , and was " SF " or Smokeless / Flashless , and used a type of piston system to force the grenade out of the cartridge , but keep the propellant and gases 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 grenade launchers a far greater effect against static targets such as bunkers , houses , and masonry . The M430 and M430A1 are 40×53mm HEDP cartridges akin to the low velocity M433 . They differ in how much armor they can penetrate , with the M430 being able to penetrate 51mm of steel plate , and the M430A1 being able to penetrate 76mm . Also produced was a special 40×53mm airburst munition for usage from either the M75 or M129 automatic grenade launchers , commonly used on 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 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 , 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 40x53mm cartridge as well . 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 consider a large shotgun . 40×46mm types include the M576 and the XM678 . The M576 contains twenty 24g metal pellets . The XM576 / XM576E1 was standardized to become the M576 . Another test variant , the XM576E2 , which had Twenty - seven 24g metal pellets without a sabot within the shot cup was deemed to spread too quickly for effective use . The only 40×53mm type is the M1001 and is a canister round filled with 115 17 - grain 2 . 0 - inch long flechette s . The choice of fin - stabilized flechettes over pellets or similar projectiles for the high velocity ammunition is most likely a product of their greater accuracy over slightly longer ranges . Smoke , signaling , and illumination cartridges . Smoke cartridges . Most numerous of the 40×46mm 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 . " 40×46mm canopy smoke grenades come in 3 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 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 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 mentioned later in this article . A 40×53mm 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 often encountered ) . 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 40x46mm caliber , serving more of a use in the individual rather than the 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 . 40x46mm cluster flares come in 3 colors : white ( M585 ) , green ( M663 ) , and red ( M664 ) . Individual flares burn for 7 seconds after ignition . The M585 is the standardization of the XM585E1 . Differences between it and the XM585 are unclear . Parachute flares come in 4 colors : white ( M583 / A1 ) , green ( M661 ) , red ( M662 ) , and orange ( XM695 ) . The parachute is designed to create a 7 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 . This Infra - Red Illumination Cartridge ( or IRIC ) was designated XM992 / M992 . 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 the Law Enforcement community for years . These cartridges are also mainly 40×46mm , as it is likely that a high velocity variant would greatly detract from their less - lethal capabilities . Oldest of these types is the riot control 40 mm gas cartridges . 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 an area 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 , 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 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 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 . More recent have been a variety of canister rounds and other less - lethal projectiles . The M1029 contains 48 rubber balls of . 48 " 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 30 years or so . Despite this , the M1006 is still potentially lethal when fired at distances under 10 meters , having an 81 meter per second muzzle velocity , as well as , being largely ineffective at distances over 50 meters . 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 users to launch the hook over a greater distance than if it had been 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 . Green ammunition . The MK281 is a new type of 40mm 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 mm x 53 Practice cartridges are precision , high - velocity training and practice cartridges . The MK281 uses the proven , patented Rheinmetall propulsion unit that enables a very low standard deviation in muzzle velocity , thereby resulting in a high degree of 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 : 40mm x 53 Cartridge MK281 Mod0 Impact Marker40mm x 53 Cartridge MK281 Mod1 Day / Night MarkerThe 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 . MK281 MOD1 cartridge truly allows operators to " train like they fight " . 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 . 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