M203 grenade launcher

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 and was introduced to US military forces during the early 1970s, replacing the M79 grenade launcher and the conceptually similar 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 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, 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, although the Marines began issuing the M320 in June 2017. The M320 features an advanced day/night sight, a double-action firing mechanism (as opposed to the M203's single-action) as well as other benefits, such as an unobstructed side-loading breech. ==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 vehicles. 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 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, there are eight different rounds for the M203: • (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 cm (2 inches) when fired straight at steel armor at or less, or, at a point target, it arms between , causes casualties within a radius, and has a kill radius of 5 meters. • (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 , produces a ground burst that causes casualties within a radius, and has a kill radius of . • (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 . The candle burns for about 40 seconds. A raised letter on the top of the round denotes the color of the parachute. • (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. • (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 . 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 indicates the color of the smoke. • (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 , and has a danger radius of . • (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 and produces a white cloud of CS gas on impact. • (M576) 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 , with a muzzle velocity of . The round has no mechanical-type fuse. ==Components==

The M203 grenade launcher system comes with a variety of components, usually including the launcher, adapters 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 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. ==Variants==

with an M203 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 M16A1, M16A2 and M16A3 rifles, and utilizes a 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 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. The weapon's barrel slides further forward than the standard American models, which allows longer rounds to be loaded. ==Users==

with a short-barreled M203 grenade launcher member with a Heckler & Koch MP5 with the RM Equipment M203PI grenade launcher rifle fitted with M203 grenade launcher rifle with K201 rifle equipped with SPG-1A • • and M203A1 for M4A1 carbines. • : M203PI variant. • • : Entered service along Colt M5 in 2024. Used by OYK. • : Bushmaster M203 used with the Bushmaster M4A3 carbine issued to Czech special forces. • • • • • • • • : M203PI variant. • • : Used by Bougainville Revolutionary Army. Captured from Papua New Guinea Defence Force. • • : Used by the Polish Special Forces. • Used by Special Actions Detachment. • • • • ==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, 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 and .22 rimfire ammo. 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. ==Data==

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. • Weapon. • Length: • Rifle and grenade launcher (overall)........................99.0 cm (39 inches) • Barrel only................................................................30.5 cm (12 inches) • Rifling............................................................................25.4 cm (10 inches) • Weight: • Launcher, unloaded.................................................1.4 kg (3.0 pounds) • Launcher, loaded.....................................................1.6 kg (3.5 pounds) • Rifle and grenade launcher, both fully loaded......5.0 kg (11.0 pounds) • Number of lands............................................................6 right hand twist • Ammunition. • Caliber............................................................................40 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 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 Note: some data differs for versions that attach to the M4 carbine. The 40 mm grenades used in the M203 (40 × 46 mm) are not the same as those used by the Mk 19 grenade launcher (40 × 53 mm), which are fired at higher velocities) ==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 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 M16A1 with a practice round File:M16A2 M203.JPEG|A U.S. Marine takes aim with an M16A2 fitted with the M203 40 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. ==See also==