View source for M203 grenade launcher

{{redirect|M-203|the highway in Michigan|M-203 (Michigan highway)}}
{{Infobox weapon
| name               = Launcher, Grenade, 40mm, M203
| image              = File:PEO M203A2 Grenade Launcher.jpg
| image_size         = 300
| caption            = M203A2
| origin             = United States
| type               = [[Grenade launcher]]
<!-- Type selection -->| is_ranged          = yes
<!-- Service history -->| service            = 1969–present<ref name="hkusa01"/>
| used_by            = See ''[[#Users|Users]]''
| wars               = [[Vietnam War]]<br>[[Laotian Civil War]]<br />[[Cambodian Civil War]]<br />[[Civil conflict in the Philippines]]<br>[[Sino-Vietnamese War]]<br>[[Cambodian–Vietnamese War]]<br/>[[Sino-Vietnamese conflicts (1979–1991)]]<br />[[Third Indochina War]]<br />[[Soviet–Afghan War]]<br>[[Falklands War]]<ref>{{cite web|url=https://www.americanrifleman.org/content/guns-of-the-falklands-war/ |title=Guns of the Falklands War}}</ref><br>[[Gulf War]]<br>[[War in Afghanistan (2001–2021)]]<br>[[Iraq War]]<br>[[War in Iraq (2013–2017)]]<br>[[Syrian Civil War]]<br>[[Gaza war]]<br>[[Russian invasion of Ukraine]]<br>[[2025 Cambodia-Thailand conflict]]
<!-- Production history -->| designer           = [[AAI Corporation|AAI]]
| design_date        = 1967–68
| manufacturer       = [[Colt's Manufacturing Company|Colt Defense]]<br>[[Diemaco]]<br>Airtronic USA<br>RM Equipment<br>[[U.S. Ordnance]]<br>[[Knight's Armament Company]]<br>[[Lewis Machine and Tool Company|Lewis Machine & Tool Company]]
| unit_cost          = US$1,082<ref>[https://web.archive.org/web/20110723004716/http://www.airtronic.net/documents/Delivery_Order.pdf M203 40mm Grenade Launcher<!-- Bot generated title -->].</ref>
| production_date    = 1969–present
| variants           = See ''[[#Variants|Variants]]''
<!-- General specifications -->| weight             = 3 lb (1.36 kg) (unloaded)
| length             = M203/M203A2: 15 in (380 mm);<br/>
M203A1: 12 in (305mm);
| part_length        = M203/M203A2: 12 in (305 mm);<br/>
M203A1: 9 in (230mm);
| width              = 
| height             = 
| crew               = <!-- Ranged weapon specifications -->
| cartridge          = [[40mm grenade#40×46mm SR|40×46mm SR]]
| caliber            = 
| action             = Single shot
| rate               = 5 to 7 round/min aimed shots<br/>
15 to 17 round/min area suppression
| velocity           = 250 ft/s (76 m/s)
| range              = 382 yds (350 m) fire-team sized area target; 164 yds (150 m) vehicle or weapon point target
| max_range          = 437 yds (400 m)
| feed               = 
| sights             = Quadrant sight or ladder sight on rifle
<!-- Artillery specifications -->| breech             = 
| recoil             = 
| carriage           = 
| elevation          = 
| traverse           = <!-- Bladed weapon specifications -->
| blade_type         = 
| hilt_type          = 
| sheath_type        = 
| head_type          = 
| haft_type          = <!-- Explosive specifications -->
| diameter           = 
| filling            = 
| filling_weight     = 
| detonation         = 
| yield              = <!-- Vehicle specifications -->
| armour             = 
| primary_armament   = 
| secondary_armament = 
| engine             = 
| engine_power       = 
| pw_ratio           = 
| suspension         = 
| speed              = 
}}
{{Listen
| image   = [[File:Crystal Project video camera.png|50px]]
| help    = no
| filename= M203 Grenade Launcher IFS.ogv
| title   = Video of M203 grenade launcher with indirect fire sight (IFS) being fired
}}
The '''M203''' is a single-shot [[40mm grenade|40 mm]] under-barrel [[grenade launcher]] designed to attach to a rifle. It uses the same rounds as the older stand-alone [[M79 grenade launcher|M79]] [[break-action]] grenade launcher, which utilizes the [[High-Low System|high-low propulsion system]] to keep recoil forces low. While compatible with many weapons, the M203 was originally designed and produced by the [[United States military]] for the [[M16 rifle]] and its [[carbine]] variant, the [[M4 carbine|M4]]. The launcher can also be mounted onto a [[Colt Canada C7 rifle|C7]], a Canadian version of the M16 rifle; this requires the prior removal of the bottom handguard. 

Stand-alone variants of the M203 exist,<ref>{{cite web|url=http://www.knightarmco.com/m203_12ga.html|title=Military|author=Knight's Armament|work=Knight's Armament|access-date=5 November 2014|url-status=dead|archive-url=https://web.archive.org/web/20120926032554/http://www.knightarmco.com/m203_12ga.html|archive-date=26 September 2012}}</ref> as do versions designed specifically for many other rifles. The device attaches under the [[barrel (firearms)|barrel]], the launcher trigger being in the rear of the launcher, just forward of the rifle [[magazine (firearms)|magazine]]. The rifle magazine functions as a hand grip when firing the M203. A separate, right-handed only, sighting system is added to rifles fitted with the M203, as the rifle's standard sights are not matched to the launcher. The version fitted to the Canadian C7 has a sight attached to the side of the launcher, either on the left or right depending on the user's needs.

==History==
The M203 was the only part of the [[United States Army]]'s [[Special Purpose Individual Weapon]] (SPIW) project to go into production. The M203 has been in service since 1969<ref name="hkusa01">{{cite web|url=http://www.hk-usa.com/le_xm320_general.html |title=Heckler&Koch |access-date=5 November 2014 |url-status=dead |archive-url=https://web.archive.org/web/20081121103021/http://www.hk-usa.com/le_xm320_general.html |archive-date=November 21, 2008}}</ref> and was introduced to [[U.S. Military|US military forces]] during the early 1970s, replacing the [[M79 grenade launcher]] and the conceptually similar [[XM148 grenade launcher|Colt XM148]] design. However, while the M79 was a stand-alone weapon (and usually the primary weapon of troops who carried it), the M203 was designed as an under-barrel device attached to an existing rifle. Because the size and weight of 40&nbsp;mm ammunition limits the quantities that can be carried, and because a grenade is often not an appropriate weapon for all engagements (such as when the target is at close range or near friendly troops), an under-barrel system has the advantage of allowing its user to also carry a rifle, and to easily switch between the two.

A new grenade launcher, the [[M320 Grenade Launcher Module|M320]], will eventually replace the M203 in the United States Army. The United States Marine Corps, Air Force, Coast Guard, and Navy continued to use the older M203,<ref>{{cite web|access-date=2025-11-03 |date=2015-01-10 |language=en |title=Army smart grenades can sense walls |url=http://www.armytimes.com/story/military/tech/2015/01/10/sagm-grenade-testing-/21409039/ |website=Army Times}}</ref> although the Marines began issuing the M320 in June 2017.<ref>{{cite web
 | url = https://www.marines.mil/News/News-Display/Article/1208875/out-with-the-old-in-with-the-new-marines-test-new-grenade-launcher-module/
 | title = Out with the old, in with the new: Marines test new grenade launcher module
 | website = Marines.mil
 | date = 2017-06-09
 | archive-url = https://web.archive.org/web/20170613045539/http://www.marines.mil/News/News-Display/Article/1208875/out-with-the-old-in-with-the-new-marines-test-new-grenade-launcher-module/
 | archive-date = 2017-06-13
 | access-date = 2025-11-03
}}</ref> The M320 features an advanced day/night sight, a [[Trigger (firearms)#Double-action|double-action]] firing mechanism (as opposed to the M203's [[Trigger (firearms)#Single action|single-action]]) as well as other benefits, such as an unobstructed side-loading breech.<ref name="ARMYMAG_01">{{cite web|url=http://www.ausa.org/webpub/DeptArmyMagazine.nsf/byid/KHYL-6L7MAD |title=XM320 Grenade Launcher Module And XM26 Modular Accessory Shotgun System - Army Magazine |url-status=dead |archive-url=https://web.archive.org/web/20060208225101/http://www.ausa.org/webpub/DeptArmyMagazine.nsf/byid/KHYL-6L7MAD |archive-date=February 8, 2006 }}</ref>

==Uses==
The M203 grenade launcher is intended to be used as close [[fire support]] against point and area targets. The round is designed to be effective at breaking through windows and exploding inside, blowing up doors, producing multiple casualties, destroying bunkers or emplacements, and damaging or disabling [[soft-skinned vehicle]]s. In the Vietnam War, U.S. Navy and Coast Guard personnel on boats would lob 40 mm grenades into the water (using the [[M79 grenade launcher]]), to preemptively attack Viet Cong swimmers ("sappers") attempting to plant explosives on anchored or moored U.S. watercraft.

Its primary purpose is to engage enemies in dead space that cannot be reached by [[direct fire]]. A well-trained M203 gunner can use their weapon to [[suppressive fire|suppress]] the enemy, based on movement and sight. In addition, the M203 can be used as a [[crowd control]] weapon when equipped with the M651 tactical CS ([[tear gas]]) grenade. While classified primarily as an anti-personnel weapon, the shaped charge featured in the HEDP round gives it the capability to penetrate lightly armored vehicles.

==Rounds==
The M203 is able to fire a variety of different rounds for many purposes. According to the ''U.S. Army Field Manual FM 3-22.31 40-MM Grenade Launcher, M203'',{{sfn|Headquarters Department of the Army|2003}} there are eight different rounds for the M203:
[[File:Overview_40_mm_Grenades.svg|thumb|40 mm ammunition line drawings]]
[[File:M16 M203 40mm ammunition.JPEG|thumb|right|An M16A2 rifle equipped with an M203 grenade launcher lies in the grass near some of the types of 40 mm ammunition available for use with the M203. The cartridges are, from left to right, multiple projectile, practice, green star flare, white star flare, red star flare and high explosive dual purpose.]]
* (M433) high-explosive dual purpose round. The HEDP round has an olive drab aluminum skirt with a steel cup attached, white markings, and a gold [[ogive]] (head of the round). It penetrates at least 5&nbsp;cm (2 inches) when fired straight at steel armor at {{convert|150|m|abbr=on}} or less, or, at a point target, it arms between {{convert|14|and|27|m|abbr=on}}, causes casualties within a {{convert|130|m|abbr=on}} radius, and has a kill radius of 5 meters.{{sfn|Headquarters Department of the Army|2003|page=3-8}}
* (M406) high-explosive round. The HE round has an olive drab aluminum skirt with a steel projectile attached, gold markings, and a yellow ogive. It arms between {{convert|14|and|27|m|abbr=on}}, produces a ground burst that causes casualties within a {{convert|130|m|abbr=on}} radius, and has a kill radius of {{convert|5|m|abbr=on}}.{{sfn|Headquarters Department of the Army|2003|page=3-9}}
* (M583A1) star parachute round. This round is white impact or bar alloy aluminum, with black markings. It is used for illumination and signals and is lighter and more accurate than comparable handheld signal rounds. The parachute attached to the round deploys upon ejection to lower the candle at {{convert|7|ft/s|abbr=on}}. The candle burns for about 40 seconds. A raised letter on the top of the round denotes the color of the parachute.{{sfn|Headquarters Department of the Army|2003|page=3-9}}
* (M585) white star cluster round. This round is white impact or bar aluminum alloy, with black markings. The attached plastic ogive has five raised dots for night identification. The round is used for illumination or signals. It is lighter and more accurate than comparable handheld signal rounds. The individual stars burn for about 7 seconds during free fall.{{sfn|Headquarters Department of the Army|2003|page=3-10}}
* (M713) ground marker round. This round is light green impact aluminum with black markings. It is used for aerial identification and for marking the location of soldiers on the ground. It arms between {{convert|15|and|45|m|abbr=on}}. If a fuse fails to function on impact, the output mixture provided in the front end of the delay casing backs up the impact feature. The color of the [[Ogive#Types and use in applied physical science and engineering|ogive]] indicates the color of the smoke.{{sfn|Headquarters Department of the Army|2003|page=3-11}}
* (M781) practice round. Used for practice, this round is blue zinc or aluminum, with white markings. It produces a yellow or orange signature on impact, arms between {{convert|14|and|27|m|abbr=on}}, and has a danger radius of {{convert|20|m|abbr=on}}.{{sfn|Headquarters Department of the Army|2003|pages=3-11−3-12}}
* (M651) CS round. This round is gray aluminum with a green casing and black markings. Though it is a multipurpose round, it is most effective for riot control and in Urban Operations. It arms between {{convert|10|and|30|m|abbr=on}} and produces a white cloud of [[CS gas]] on impact.{{sfn|Headquarters Department of the Army|2003|pages=3-11−3-12}}
* [[M576 40mm grenade|(M576)]]<ref>{{cite book |last1=United States Congress House Committee on the Judiciary Subcommittee on Commercial and Administrative Law |title=Protection of Lawful Commerce in Arms Act: Hearing Before the Subcommittee on Commercial and Administrative Law of the Committee on the Judiciary, House of Representatives, One Hundred Eighth Congress, First Session on H.R. 1036, April 2, 2003 |date=2003 |publisher=U.S. Government Printing Office |isbn=978-0-16-070377-5 |page=17 |url=https://books.google.com/books?id=FSRowYdaJOcC |access-date=21 September 2023 |language=en}}</ref> buckshot round. This round is olive drab with black markings. Though it is a multipurpose round, it is most effective in thick vegetated areas or for room clearing. Inside, it has 20 metal pellets, each weighing {{convert|24|gr|abbr=on}}, with a muzzle velocity of {{convert|269|m/s|abbr=on}}. The round has no mechanical-type fuse.{{sfn|Headquarters Department of the Army|2003|page=3-12}}

==Components==
[[File:M203 with SU-277 GLS.jpg|thumb|175x175px|M203 with SU-277/PSQ GLS]]
The M203 grenade launcher system comes with a variety of components, usually including the launcher, [[adapter]]s for attachment to assault rifles, and leaf sights (which can be used with the rifle's front sight post). M203s can also come with quadrant sights, mounting to an [[Picatinny rail|MIL-STD 1913 Rail]], or to the carrying handle of an M16 rifle.

The [[U.S. Marine Corps]] also uses the SU-277/PSQ Grenade Launcher Sight (GLS), which features a holographic red dot for improved aiming, integrated ballistic data for automatic adjustment based on ammunition, infrared aiming laser, and a compact, lightweight design.<ref>{{Cite web |title=Zeroing in: 3rd Marine Regiment tests new sight |url=https://www.marcorsyscom.marines.mil/News/News-Article-Display/Article/509584/zeroing-in-3rd-marine-regiment-tests-new-sight/ |access-date=2024-12-31 |website=Marine Corps Systems Command |language=en-US}}</ref>

==Variants==
[[File: M16A2 Rifle with M203 Grenade Launcher (7414627064).jpg|thumb|right|[[M16 rifle|M16A2]] with an M203]]
[[File:M4 Carbine with M203 Grenade Launcher (7414626424).jpg|thumb|right|[[M4A1]] with an M203A2]]

There are numerous variants of the M203 manufactured in the U.S., and throughout the world, for various applications. These vary chiefly in the length of the barrel, attachment type, and quick detach (QD) capability.

The ''standard M203'' is intended for permanent attachment to the [[M16 rifle|M16A1]], [[M16 rifle|M16A2]] and [[M16 rifle|M16A3]] rifles, and utilizes a {{convert|12|in|cm|abbr=on}} rifled barrel. The M203 unmodified to an A1/A2 series will not fit on the M4 carbine series.

The U.S. M203A1 has a barrel of 12 inches, while the [[SOPMOD]] M203A1 has a {{convert|9|in|cm|abbr=on}} barrel. The M203A1 is intended for use with the M4 and M4A1 carbines, and uses a special bracket mount consisting of three screws and lacing wire. Only M203A2s consist of a quick release bracket.

The Canadian M203A1 by Diemaco (now Colt Canada) is a similar design with a different mounting system that does not require mounting points of the same profile as the M16A1 rifle's.<ref name="M203">[https://www.sfu.ca/casr/101-army-m203-grenade.htm Diemaco M203A1.] {{webarchive|url=http://archive.wikiwix.com/cache/20170824223002/https://www.sfu.ca/casr/101-army-m203-grenade.htm |date=2017-08-24}} Retrieved on January 5, 2008.</ref> The weapon's {{convert|9|in|cm|abbr=on}} barrel slides further forward than the standard American models, which allows longer rounds to be loaded.<ref name="M203" /> This model is identifiable by the increased distance between the grenade launcher's barrel axis and the rifle's.<ref name="M203" /> 

The M203A2 is intended for use with the M4 series/M16A4 and now also authorized on the M16A2 rifle as the  modular weapon system (MWS). Using standard {{convert|12|in|cm|abbr=on}} barrels, the grenade launcher is intended for use in concert with the Knight's Armament Company M5 RAS. The M5 MWS rail system became authorized in December 2008 for the M16A2 Rifle. An advantage of this system is the use of range-finding optics to make precise targeting easier.

The M203PI system is used for attachment of the M203 to other rifles, including, but not limited to, the [[Steyr AUG]], [[Heckler & Koch G3]], and the [[Heckler & Koch MP5|MP5 sub-machine gun]].{{sfnp|Hogg|1994|p=213}} Most of these other companies have since devised 40 mm grenade launchers custom integrated with the weapon.

The M203 DAX has a double-action trigger and longer breech opening to accommodate less-lethal rounds.

The M203 and M203A1 are currently manufactured by AIRTRONIC USA, Inc. of Elk Grove Village, Illinois for the U.S. Department of Defense under contract numbers W52H09-06-D-0200 and W52H09-06-D-0225. Each contract is for up to 12,000 units. Each unit is shipped with hand guard, leaf sight and quadrant range sight. The contracts unit prices vary from $840 to $1,050 each. The production rate is 1,500 units per month. The M203PI is manufactured for both the U.S. Department of Defense and for commercial sales to law enforcement agencies both in the United States and abroad, and for foreign military sales by [http://www.rm-equipment.com RM-Equipment Inc.] of [[Miami]], Florida.

The M203 37 mm version became available on the U.S. market in 2017. It is available in a {{convert|9|in|cm|abbr=on}} and a {{convert|12|in|cm|abbr=on}} barrel version.  They are scroll marked: "Launcher, Grenade M203 40mm", even though they are actually 37 mm devices.  These 37 mm versions are considered a "title 1 firearm", and are not classified as "destructive devices" under the NFA.  These launchers can be sold the same as regular firearms on an ATF Form 4473.<ref name="armsunlimited.com">{{cite web|url=https://www.armsunlimited.com/Colt-M203-37mm-Grenade-Launcher-for-M16-M4-AR15-p/r0810.htm|title=Colt M203 37mm Grenade Launcher - ''M4 Profile 12'' Barrel|website=ArmsUnlimited.com|url-status=live|archive-url=https://web.archive.org/web/20171116203944/https://www.armsunlimited.com/Colt-M203-37mm-Grenade-Launcher-for-M16-M4-AR15-p/r0810.htm|archive-date=2017-11-16}}</ref>

==Users==
[[Image:Pte Corey Dwyer UNDOF Syria (14381662446) (2).jpg|right|thumb|Irish soldier with a [[Steyr AUG]] with a short-barreled M203 grenade launcher]]
[[File:2015 National Day Parade, Kuala Lumpur AB16.JPG|thumb|Malaysian [[Pasukan Gerakan Khas]] member with a [[Heckler & Koch MP5]] with the RM Equipment M203PI grenade launcher]]
[[File:Flickr - Israel Defense Forces - Pose for the Camera.jpg|thumb|Israeli soldier with an [[TAR-21|IWI Tavor-21]] rifle fitted with M203 grenade launcher]]
[[File:US Marines operate ROK weapons 150205-M-RZ020-004.jpg|thumb|right|South Korean [[Daewoo K2]] rifle with K201]]
[[File:M203 Grenade Launcher Operators Map 26.01.2025.png|thumb|Map with M203 grenade launcher users in blue]]
[[File:Pindad SS2-V4A2 with SPG-1A at Indo Defence 2024.jpg|thumb|Indonesian [[Pindad SS2]] rifle equipped with SPG-1A]]
<!--READ FIRST: This section is for cited entries only. Please do not add entries into this list without a citation from a reliable source. All entries without a citation will be removed. Thank you.-->
* {{flag|Afghanistan}}<ref>{{cite web|title=Afghan National Security Forces Order of Battle|url=http://www.longwarjournal.org/multimedia/ANSF%20OOBpage4-ANA.pdf|publisher=Long War Journal|access-date=3 November 2011|url-status=live|archive-url=https://web.archive.org/web/20120607171044/http://www.longwarjournal.org/multimedia/ANSF%20OOBpage4-ANA.pdf|archive-date=7 June 2012}}</ref>
* {{flag|Albania}}<ref name="Rottman_US_Launchers"/>
* {{flag|Argentina}}<ref name="Rottman_US_Launchers"/>
* {{flag|Australia}}: ''M203PI'' variant for F88 Austeyr,<ref name="jones2009">Jones, Richard D. ''Jane's Infantry Weapons 2009/2010''. Jane's Information Group; 35 edition (January 27, 2009). {{ISBN|978-0-7106-2869-5}}.</ref> and ''M203A1'' for M4A1 carbines.
* {{flag|Austria}}: ''M203PI'' variant.<ref name="jones2009"/>
* {{flag|Bangladesh}}<ref name="Rottman_US_Launchers"/>
* {{flag|Bolivia}}{{citation needed|date=October 2024}}
* {{flag|Brazil}}<ref name="jones2009"/>
* {{flag|Brunei}}<ref name="jones2009"/>
* {{flag|Cameroon}}<ref name="jones2009"/>
* {{flag|Canada}}: [[Canadian Forces]]: M203A1 variant produced by [[Colt Canada]] (formerly [[Diemaco]] prior to 2005).<ref>{{cite web|url=http://www.army.gc.ca/lfwa/photos_tfa_Feb06.asp |title=Task Force Afghanistan Photos |access-date=2010-04-18 |url-status=dead |archive-url=https://web.archive.org/web/20110720034424/http://www.army.gc.ca/lfwa/photos_tfa_Feb06.asp |archive-date=2011-07-20 }}</ref><ref>{{cite web|url=http://www.army.gc.ca/land-terre/news-nouvelles/story-reportage-eng.asp?id%3D517 |title=Junior commanders lead during tactical live fire exercise |access-date=2010-04-18 |url-status=dead |archive-url=https://web.archive.org/web/20110720034436/http://www.army.gc.ca/land-terre/news-nouvelles/story-reportage-eng.asp?id=517 |archive-date=2011-07-20 }}</ref>
* {{flag|Chile}}<ref name="jones2009"/>
* {{flag|Congo-Kinshasa}}<ref>{{cite web |author=Frida Berrigan and Michelle Ciarrocca |url=http://www.worldpolicy.org/projects/arms/reports/smallarms.htm |title=Report: Profiling the Small Arms Industry - World Policy Institute - Research Project |publisher=World Policy Institute |date=2000-11-01 |access-date=2017-08-22 |url-status=dead |archive-url=https://web.archive.org/web/20171011093831/http://www.worldpolicy.org/projects/arms/reports/smallarms.htm |archive-date=2017-10-11 }}</ref>
* {{Flag|Cyprus}}: Entered service along [[M16 rifle#M5 carbine|Colt M5]] in 2024. Used by [[Underwater Demolition Team (Cyprus)|OYK]].<ref>{{Cite web |date=2024-12-12 |title=Op-ed: American weapons for the National Guard |url=https://in-cyprus.philenews.com/local/op-ed-american-weapons-for-the-national-guard/ |access-date=2024-12-12 |website=in-cyprus.philenews.com |language=en-US}}</ref><ref>{{Cite web |last=Solutions |first=BDigital Web |title=Cutting-edge American rifles boost Cyprus' security forces |url=https://knews.kathimerini.com.cy/en/news/cutting-edge-american-rifles-boost-cyprus-security-forces |access-date=2024-12-12 |website=knews.com.cy}}</ref>
* {{flag|Czech Republic}}: Bushmaster M203 used with the Bushmaster M4A3 carbine issued to Czech special forces.<ref>{{cite web |url=http://www.army.cz/assets/files/9334/zbrane_definit.pdf |title=Archived copy |access-date=2010-11-12 |url-status=live |archive-url=https://web.archive.org/web/20120229001255/http://www.army.cz/assets/files/9334/zbrane_definit.pdf |archive-date=2012-02-29 }}</ref>
* {{flag|Denmark}}<ref>{{cite web|url=http://forsvaret.dk/hok/documents/hok/040927-041122/041101_hks_nlw_folder.pdf |title=Archived copy |access-date=2010-04-12 |url-status=dead |archive-url=https://web.archive.org/web/20110606191254/http://forsvaret.dk/hok/documents/hok/040927-041122/041101_hks_nlw_folder.pdf |archive-date=2011-06-06 }}</ref>
* {{flag|Dominican Republic}}<ref name="Rottman_US_Launchers"/>
* {{Flag|East Timor}}<ref name="Rottman_US_Launchers"/>
* {{flag|Ecuador}}<ref name="jones2009"/>
* {{flag|Egypt}}<ref>{{cite web|url=http://world.guns.ru/grenade/usa/m203-e.html|title=Modern Firearms|date=28 October 2010 |access-date=5 November 2014|url-status=live|archive-url=https://web.archive.org/web/20141118170130/http://world.guns.ru/grenade/usa/m203-e.html|archive-date=18 November 2014}}</ref>
* {{flag|El Salvador}}<ref name="jones2009"/>
* {{flag|Estonia}}<ref>{{cite web |title=40mm rauaalune granaadiheitja M203 |url=https://mil.ee/kaitsevagi/tehnika/relvad/#t-40mm-relvaalune-granaadiheitja-m203 |website=mil.ee |publisher=Estonian Defence Forces |access-date=14 October 2020}}</ref>
* {{flag|France}}<ref>{{cite web|url=http://world.guns.ru/assault/as21-e.htm|title=Modern Firearms|access-date=5 November 2014|url-status=live|archive-url=https://web.archive.org/web/20100826055244/http://world.guns.ru/assault/as21-e.htm|archive-date=26 August 2010}}</ref>
* {{flag|Gabon}}<ref name="jones2009"/>
* {{flag|Greece}}<ref name="jones2009"/>
* {{flag|Guatemala}}<ref name="jones2009"/>
* {{flag|Honduras}}<ref name="jones2009"/>
* {{flag|India}}<ref name="jones2009"/>
* {{flag|Indonesia}}: Locally produced by [[Pindad|PT Pindad]] as SPG-1.<ref name="jones2009"/>
* {{flag|Iraq}}<ref name="Rottman_US_Launchers"/>
* {{flag|Ireland}}: [[Irish Army]] specialist units, including the [[Army Ranger Wing]] (ARW).<ref name="jones2009"/><ref>{{cite web|url=http://www.military.ie/army/equipment/weapons/inf/m203/m203.htm|title=Army Weapons - M203 Grenade Launcher|access-date=5 November 2014|url-status=dead|archive-url=https://web.archive.org/web/20101126115506/http://military.ie/army/equipment/weapons/inf/m203/m203.htm|archive-date=26 November 2010}}</ref>
* {{flag|Israel}}<ref name="jones2009"/>
* {{flag|Italy}}<ref name="jones2009"/>
* {{flag|Japan}}: Used by the [[Japan Ground Self-Defense Force]].<ref>{{Cite web |title=Colt / AAI M203 40mm Single-Shot, Breech-Loading Under-Barrel Grenade Launcher (UBGL) Specifications and Pictures |url=https://www.militaryfactory.com/smallarms/detail.php?smallarms_id=6 |access-date=2024-03-29 |website=www.militaryfactory.com}}</ref>
* {{flag|Jordan}}<ref name="jones2009"/>
* {{flag|Kuwait}}<ref name="jones2009"/>
* {{flag|Lebanon}}<ref name="jones2009"/>
* {{flag|Liberia}}<ref name="jones2009"/>
* {{flag|Malaysia}}<ref name="jones2009"/>
* {{flag|Mexico}}<ref name="jones2009"/>
* {{flag|Myanmar}}<ref name="jones2009"/>
* {{Flag|Netherlands}}<ref name="Rottman_US_Launchers">{{cite book|last= Rottman|first= Gordon L.|title= US Grenade Launchers: M79, M203, and M320|date= 21 September 2017|url= https://books.google.com/books?id=yNQxDwAAQBAJ|publisher= Osprey Publishing|page= 37|isbn= 978-1-4728-1952-9|access-date= 2017-12-21|archive-url= https://web.archive.org/web/20171222051452/https://books.google.nl/books/about/US_Grenade_Launchers.html?id=yNQxDwAAQBAJ&redir_esc=y|archive-date= 2017-12-22|url-status= live}}</ref>
* {{flag|New Zealand}}: ''M203PI'' variant.<ref name="jones2009"/>
* {{flag|Oman}}<ref name="jones2009"/>
* {{flag|Pakistan}}: Used by the [[Pakistan Army]].<ref>{{cite web|title=M203|url=http://weaponsystems.net/weapon.php?weapon=BB02%20-%20M203|url-status=live|archive-url=https://web.archive.org/web/20141224070947/http://weaponsystems.net/weapon.php?weapon=BB02%20-%20M203|archive-date=2014-12-24}}</ref>
* {{flag|Panama}}<ref name="jones2009"/>
* {{flag|Papua New Guinea}}<ref name=Alpers>{{cite book|last=Alpers|first=Philip|editor1-last=Karp|editor1-first=Aaron|title=The Politics of Destroying Surplus Small Arms: Inconspicuous Disarmament|date=2010|pages=168–169|publisher=Routledge Books|location=Abingdon-on-Thames|isbn=978-0-415-49461-8}}</ref>
** {{flag|Bougainville}}: Used by [[Bougainville Revolutionary Army]]. Captured from [[Papua New Guinea Defence Force]].<ref>{{cite web |author=Will Bundy |url=http://wineandbowties.com/ideas/nature/the-coconut-revolution/ |title=THE COCONUT REVOLUTION |publisher=Wine & Bowties |date=2012-12-14 |access-date=2017-08-22 |url-status=dead |archive-url=https://web.archive.org/web/20170823072452/http://wineandbowties.com/ideas/nature/the-coconut-revolution/ |archive-date=2017-08-23 }}</ref>
* {{flag|Philippines}}<ref name="jones2009"/> Formerly manufactured by [[Floro International Corporation]] as the FIC M203.<ref>{{cite web|url=http://www.janes.com/articles/Janes-Infantry-Weapons/Floro-FIC-M203-40-mm-under-barrel-grenade-launcher-Philippines.html |title=Archive for Floro FIC M203 40 mm under-barrel grenade-launcher (Philippines), Light support weapons |access-date=2010-09-09 |date=2010-09-09 |publisher=Jane's Information Group |url-status=dead |archive-url=https://web.archive.org/web/20180510052517/http://www.janes.com/articles/Janes-Infantry-Weapons/Floro-FIC-M203-40-mm-under-barrel-grenade-launcher-Philippines.html |archive-date=May 10, 2018 }}</ref><ref>[http://www.floro-intl.com/m203.html FIC M203 40 mm under-barrel grenade launcher, official page on the manufacturer's website] {{webarchive|url=https://web.archive.org/web/20110704062934/http://www.floro-intl.com/m203.html |date=2011-07-04 }} Retrieved on September 11, 2010</ref>
* {{flag|Poland}}: Used by the [[Polish Special Forces]].
*{{PRT}} Used by [[Special Actions Detachment]].
* {{flag|Qatar}}<ref name="jones2009"/>
* {{flag|Romania}}<ref name="Rottman_US_Launchers"/>
* {{flag|Saudi Arabia}}<ref name="Rottman_US_Launchers"/>
* {{flag|Sierra Leone}}<ref>{{cite web|url=https://sites.google.com/site/worldinventory/wiw_af_sierraleone|title=Google Sites|website=sites.google.com|url-status=live|archive-url=https://web.archive.org/web/20161124203938/https://sites.google.com/site/worldinventory/wiw_af_sierraleone|archive-date=2016-11-24}}</ref>
* {{flag|Singapore}}<ref name="jones2009"/>
* {{flag|South Korea}}: A locally manufactured clone, designated ''K201'', is deployed on the [[Daewoo K2|K2 assault rifle]].<ref name="jones2009"/>
* {{flag|Sri Lanka}}<ref name="jones2009"/>
* {{flag|Sweden}}: Designated as ''Granattillsats 40 mm Ak'' in the [[Swedish Armed Forces]].<ref name="jones2009"/>
* {{flag|Thailand}}<ref name="jones2009"/>
* {{flag|Turkey}}<ref name="jones2009"/>
* {{flag|Ukraine}}<ref>{{cite web|url=https://armourersbench.com/2023/12/17/the-rarest-grenade-launcher-in-ukraine/|title=The Rarest Grenade Launcher in Ukraine|date=17 December 2012|website=The Armourer's Bench}}</ref>
* {{flag|United Arab Emirates}}<ref name="jones2009"/>
* {{flag|United Kingdom}}: [[Special Air Service]].<ref>{{cite web|url=http://www.eliteukforces.info/special-air-service/weapons/m203.php|title=SAS - Weapons - M203|website=www.eliteukforces.info|url-status=live|archive-url=https://web.archive.org/web/20170803130253/http://www.eliteukforces.info/special-air-service/weapons/m203.php|archive-date=2017-08-03}}</ref>
* {{flag|United States}}<ref name="jones2009"/>
* {{flag|Vietnam}}: A local derivative called the [[OPL-40M]]. <ref>https://globalbusinesspress.net/stories/vietnamese-people-army-to-start-mass-producing-opl-40m-grenade-launcher/</ref>

==Civilian ownership in the United States==
In the United States, M203 grenade launcher attachments fitted with the standard rifled 40 mm barrels are classified as "destructive devices" under the [[National Firearms Act]] (NFA) part 26 U.S.C. 5845, 27 CFR 479.11,<ref>[http://www.atf.treas.gov/firearms/nfa/nfa_handbook/chapter2.pdf ATF NFA Handbook, Chapter 2] {{webarchive|url=https://web.archive.org/web/20080920055327/http://atf.treas.gov/firearms/nfa/nfa_handbook/chapter2.pdf |date=2008-09-20 }}.</ref> because they are a "non-sporting" firearm with a bore greater than one-half inch in diameter. M203s are on the civilian NFA market but are limited as most manufacturers have quit selling to the civilian markets. New M203 launchers sell for approximately $2,000 plus a $200 transfer tax, and new manufacture 40 mm training ammunition is available for $5 to $10 per cartridge, as of March 2011. High explosive 40 mm grenades are available for $400 to $500 per cartridge; however, they are exceedingly rare on the civilian market, as each grenade constitutes a destructive device on its own, and must be registered with the federal government, requiring payment of a $200 tax and compliance with storage regulations for high explosives. There are also sub-caliber adapters available for the 40 mm M203 (and M79) grenade launchers, which will allow the use of standard 12-gauge shotgun shells<ref>{{cite web|url=http://www.mr40mm.com/index_files/Page712.htm|title=12ga|access-date=5 November 2014|url-status=dead|archive-url=https://web.archive.org/web/20141106005451/http://www.mr40mm.com/index_files/Page712.htm|archive-date=6 November 2014}}</ref> and .22 rimfire ammo.<ref>{{cite web|url=http://www.mr40mm.com/products|title=RANDY SHIVAK - PRODUCTS|access-date=5 November 2014|url-status=dead|archive-url=https://web.archive.org/web/20080606140211/http://www.mr40mm.com/products|archive-date=6 June 2008}}</ref>  

In 2017, a 37 mm civilian version became available on the market that is not considered an NFA weapon.  As the 37 mm version is not classified as a "destructive device", it can be sold to the general public on the same ATF Form 4473 as most other firearms. The 37 mm launcher can use 37 mm flare rounds already available on the market. This civilian version sells for around $2,000 and accessories such as quick detach mounts and a quadrant sight are also available.<ref name="armsunlimited.com"/>

==Data==
[[File:M203 Shooting.jpg|thumb|right|Range qualification with an M203 using the leaf sight]]

The following technical data for the M203/M203A1 grenade launcher comes directly from the ''U.S. Army Field Manual FM 3-22.31 40-MM Grenade Launcher, M203.''{{sfn|Headquarters Department of the Army|2003}}
* '''Weapon.'''
** '''Length:'''
*** '''Rifle and grenade launcher (overall)'''........................99.0&nbsp;cm (39 inches)
*** '''Barrel only'''................................................................30.5&nbsp;cm (12 inches)
** '''Rifling'''............................................................................25.4&nbsp;cm (10 inches)
** '''Weight:'''
*** '''Launcher, unloaded'''.................................................1.4&nbsp;kg (3.0 pounds)
*** '''Launcher, loaded'''.....................................................1.6&nbsp;kg (3.5 pounds)
*** '''Rifle and grenade launcher, both fully loaded'''......5.0&nbsp;kg (11.0 pounds)
** '''Number of lands'''............................................................6 right hand twist
* '''Ammunition.'''
** '''Caliber'''............................................................................40&nbsp;mm
** '''Weight'''.............................................................................About 227 grams (8 ounces)
* '''Operational characteristics.'''
** '''Action'''.............................................................................Single shot
** '''Sights:'''
*** '''Front'''..........................................................................Leaf sight assembly
*** '''Rear'''...........................................................................Quadrant sight
** '''Chamber pressure'''.........................................................206,325 kilopascals (35,000 psi)
** '''Muzzle velocity'''..............................................................76&nbsp;m/s (250 fps)
** '''Maximum range'''.............................................................About 400 meters (1,312 feet)
*** '''Maximum effective range:'''
**** '''Fire-team sized area target'''................................350 meters (1,148 feet)
**** '''Vehicle or weapon point target'''.........................150 meters (492 feet)
** '''Minimum safe firing range (HE):'''
*** '''Training'''.....................................................................130 meters (426 feet)
*** '''Combat'''......................................................................31 meters (102 feet)
** '''Minimum arming range'''.................................................About 14 to 38 meters (46 to 125 feet)
** '''Rate of fire'''......................................................................5 to 7 rounds per minute
** '''Minimum combat load'''...................................................36 HE rounds

<small>'''Note:''' some data differs for versions that attach to the M4 carbine.</small>

The 40&nbsp;mm grenades used in the M203 (40 × 46&nbsp;mm) are not the same as those used by the [[Mk 19 grenade launcher]] (40 × 53&nbsp;mm), which are fired at higher velocities)

==Gallery==
<gallery>
File:M430A1 Cutaway.svg|Diagram of an HEDP.
File:US Navy 040529-N-8796S-043 40mm Practice grenades are lined up for loading.jpg|40 mm practice grenades.
File:40mm casing, inside.jpg|Inside view of a spent casing for a 40 mm grenade, showing the internal pressure chamber for the high-low pressure system.
File:US Navy 080806-N-7730P-202 Aviation Electronic's Technician 3rd Class Awail Hassen loads a high explosive point detonated 40MM grenade round into an M203 grenade launcher.jpg|Navy sailor loading an M203 attached to an [[M16 rifle#M16A2|M16A2]] with a high explosive round.
File:Loading M203 40 mm grenade launcher attached to an M16 rifle.jpg|Loading an M203 attached to an [[M16 rifle#XM16E1 and M16A1 (Colt Model 603)|M16A1]] with a practice round
File:M16A2 M203.JPEG|A [[U.S. Marine]] takes aim with an [[M16 rifle|M16A2]] fitted with the M203 40&nbsp;mm grenade launcher.
File:US Navy 101016-N-0475R-992 Steelworker 3rd Class Jesus Bridges, a Seabee assigned to Naval Mobile Construction Battalion (NMCB) 5.jpg|M4 carbine with M203A1 (9 in barrel), US Navy Seabees in Afghanistan 2010.
</gallery>

==See also==
* [[Grenadier]]
* [[Rifle grenade]]
* [[List of individual weapons of the U.S. Armed Forces]]
* [[United States 40 mm grenades]]

'''Other under-barrel grenade launchers'''
* [[Heckler & Koch AG36|AG36]] – widely used grenade launcher from Heckler & Koch
* [[M320 Grenade Launcher Module|M320]] – US Army M203 successor and AG36 derived
* [[FN SCAR#Enhanced Grenade Launcher Module|FN40GL]] – FN Herstal Mk 13 Mod 0 developed for FN SCAR and US SOCOM
* [[MEI HELLHOUND]] – 40 mm ammunition development
* [[GP-25]] – 40 mm under-barrel grenade launcher for [[AK-47|Kalashnikov]] series rifles
* [[Type 91 grenade launcher]] – 35 mm under-barrel grenade launcher for the Chinese [[QBZ-95]] rifle

'''Related'''
* [[KAC Masterkey]] – under-barrel shotgun
* [[M26 Modular Accessory Shotgun System|M26 Modular Accessory Shotgun System (MASS)]] – under-barrel shotgun

==References==
{{reflist|2}}

==Bibliography==
* {{cite report |last1=Headquarters Department of the Army |title=FM 3-22.31 (FM 23-31) 40-MM Grenade Launcher, M203, M203 |date=13 February 2003 |publisher=Berlin Information-center for Transatlantic Security |location=Washington D.C. |url=https://www.bits.de/NRANEU/others/amd-us-archive/FM3-22.31%2803%29.pdf |access-date=21 September 2023}}
* {{cite book |last=Hogg |first=Ian V.|year=1994 |title=Jane's Infantry Weapons, 1994-95 |publisher= Jane's Information Group|isbn=978-0710611598}}

==External links==
{{Commons and category|M203}}

* [http://www.fas.org/man/dod-101/sys/land/m433.htm M433 40mm Cartridge High-explosive dual purpose (HEDP) round specs]
* [https://web.archive.org/web/20070125042041/http://www.martin-electronics.com/ Martin Electronics, Inc. Home Page] – 40&nbsp;mm Ammunition
* [https://web.archive.org/web/20100922130940/http://www.asianmilitaryreview.com/upload/200712032016291.pdf The Infantry's Explosive Punch (Asian Military Review article)]
{{ModernUSInfWeaponsNav}}
{{Canadian Forces Land Force Command}}
{{Current French infantry weapons}}
{{Pindad}}

{{DEFAULTSORT:M203 Grenade Launcher}}
[[Category:40×46mm grenade launchers]]
[[Category:Grenade launchers of the United States]]
[[Category:United States Marine Corps equipment]]
[[Category:Teargas grenade guns]]
[[Category:Weapons and ammunition introduced in 1969]]
[[Category:Underbarrel weapons]]