The M203 Grenade Launcher’s Decades of Service Are Proof of Its Effectiveness

Photo Credit: DOD / Getty Images
Photo Credit: DOD / Getty Images

Throughout the course of the Vietnam War, the US Army developed a number of grenade launchers to aid forces in Southeast Asia. One of those was the M203, a single-shot under-barrel launcher designed to attach to shoulder-fired rifles.

Designing a new weapon for close combat

The M203 grenade launcher was designed by AAI for close combat in areas that couldn’t be reached by direct fire. It was intended to be a “tactical” accessory for the M16 rifle and its variant, the M4 carbine, and was developed in response to the US Army’s Grenade Launcher Attachment Development (GLAD) program.

After being type-classified in 1968, the Army awarded AAI a contract to produce 600 for use in Vietnam. At a cost of $1,082 USD per unit, the launcher is currently manufactured by Colt Defense, Lewis Machine & Tool Company, Diemaco, Knights Armament Company, Airtronic USA, US Ordnance and RM Equipment.

Members of the US 173rd Airborne walking away from a helicopter
The US 173rd Airborne are supported by helicopters during the Iron Triangle assault in Vietnam. (Photo Credit: Tim Page / CORBIS / Getty Images)

There are numerous variants of the M203 available, with the differences being in the attachment, length of the barrel and their quick detach (QD) capabilities. Stand-alone variants exist, as do those designed for rifles used by other countries, such as the Canadian C7.

The M203’s specifications

The M203 clocks in at just three pounds, with a barrel length of 12 inches and an overall length of 15 inches. It attaches to the under-barrel of a rifle, with the trigger just forward of the magazine. This is different than the M79 grenade launcher, a stand-alone weapon, and is to the advantage of the operator, as the under-barrel system allows them to easily switch between a rifle and the M203.

M203 grenade launcher attached to an M16 rifle
Reloading an M203 grenade launcher attached to an M16 rifle. (Photo Credit: STAFF SERGEANT JOHN K. MCDOWELL / Wikimedia Commons / Public Domain)

The 40×46 SR mm ammunition used by the M79 was passed to the M203, due to its effectiveness in breaking through buildings, destroying bunkers, damaging soft-skinned vehicles and producing mass casualties. The launcher is also equipped to fire a number of other rounds, including:

  • M433 high-explosive dual purpose round
  • M576 buckshot round
  • M406 high-explosive round
  • M651 CS (tear gas) round
  • M583A1 star parachute round
  • M781 practice round
  • M585 white star cluster round
  • M713 ground marker round

While most effective at 164 yards when targeting vehicles and at 382 yards for team-sized area targets, the M203 has a maximum firing range of 437 yards. It is typically fired from the shoulder in either a prone, standing or kneeling position. Operators don’t have to fear the possibility of backblast hazard, and it has minimal muzzle blast hazard.

US Marine firing an M203 grenade launcher
US Marine Corps Lance Cpl. Eric Martinez firing an M203 grenade launcher during weapons familiarization training at Camp Lejeune, North Carolina, 2019. (Photo Credit: Pfc. Zane Ortega / U.S. Marine Corps / Wikimedia Commons / Public Domain)

As the M203 doesn’t come equipped with a sight, one must be fitted to the rifle the launcher is attached to. As such, it comes with various components, including leaf and quadrant sights, along with adaptors that allow it to attach to different rifles.

The weapon isn’t without its faults

Despite its decades of use, the M203 grenade launcher has a number of issues users have to contend with. For starters, it adds both bulk and weight to a serviceman’s rifle, and the fore grips aren’t that great, as they have to be placed in an area that won’t interfere with the reloading process. As well, the rifle-launcher setup is said to be particularly noisy, as the rifle’s swing swivel hits against the M203.

Navy SEALs holding M203 grenade launchers
Navy SEALs participating in tactical warfare training. The SEAL in the foreground is carrying a field radio and is armed with a Colt Commando assault rifle equipped with an M203 grenade launcher. (Photo Credit: CORBIS / Getty Images)

There are also a number of safety issues. The M203 doesn’t have a safety mechanism built into it, and it’s prone to falling off a rifle after a shot is fired. Not only is it tedious to reinstall, it also puts the operator in a dangerous situation. There were also initial issues with the M203 suffering from reliability issues in cold weather conditions, but these have since been remedied.

Vietnam War-present: The M203’s use in combat

After rigorous testing, the M203 grenade launcher was introduced to US military forces operating in Vietnam in the early 1970s. It was incredibly useful, leading to its use in other conflicts involving the US, including the 1983 invasion of Grenada, UN peacekeeping missions in Lebanon, the Gulf War and a host of other operations in Bosnia, Haiti and Somalia in the 1990s.

In recent years, the US has made use of the weapon during the War in Afghanistan and the Iraq War. It’s also used by a large portion of the world’s military powers, meaning it also saw use during the Laotian Civil War, the Cambodian Civil War, the Sino-Vietnamese War, the Cambodian Vietnamese War, the Third Indochina War and, most recently, the Syrian Civil War.

US troops manning 105 mm Howitzers
US troops during the invasion of Grenada, October 27, 1983. (Photo Credit: Bettmann / Getty Images)

In 2019, the Pentagon began replacing the M203 with a new grenade launcher, the M320. The M320 is a lightweight launcher known for its safer operation, improved ergonomics, and the fact it can be used as either its own weapon or attached to the under-barrel of rifles. It was first introduced to the Army and has since seen used by the US Marine Corps.

Clare Fitzgerald

Clare Fitzgerald is a Writer and Editor with eight years of experience in the online content sphere. Graduating with a Bachelor of Arts from King’s University College at Western University, her portfolio includes coverage of digital media, current affairs, history and true crime.

Among her accomplishments are being the Founder of the true crime blog, Stories of the Unsolved, which garners between 400,000 and 500,000 views annually, and a contributor for John Lordan’s Seriously Mysterious podcast. Prior to its hiatus, she also served as the Head of Content for UK YouTube publication, TenEighty Magazine.

In her spare time, Clare likes to play Pokemon GO and re-watch Heartland over and over (and over) again. She’ll also rave about her three Maltese dogs whenever she gets the chance.

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