When the M79 grenade launcher was developed in the 1960s, it received extreme feedback. Some loved it, and those who absolutely despised using it. 

First of its Type

The journey of the M79 grenade launcher began after World War II and lasted through the Korean War a few years later. Then, the US Army decided that its regular rifle grenades were insufficient for general-purpose fire support. In addition, these standard rifle grenades were not competitive compared to other rifle grenades, plus they were very slow to launch.

As a result, the US Army started Project Niblick. It attempted to increase firepower through an explosive projectile more accurate than rifle grenades with a different range and more portable than a mortar. In 1952, they were able to identify through the project that a spherical 40 mm projectile with an explosive charge would be the most ideal to do the task. Moreover, they discovered that a cylindrical 40 mm shell with a rounded nose worked best. The round nose allowed it to hold a larger volume of explosives and had much better ballistics. Furthermore, it was determined that the 40 mm grenades needed to be fired from the unitary cartridge using a low-pressure charge.

M79 Grenade Launcher. (US Air Force from USA, Public domain, via Wikimedia Commons)

Springfield Armory was tapped to produce the weapons, and the result is this single-shot, shoulder-fire, break-action grenade launcher, the first of its type. It is chambered to fire 40 x 46 mm rounds to keep recoil forces low. Different variants of its 40 mm rounds have been produced. Here’s a partial listing:

  • M381 HE (High Explosive) round
  • M382 TP (Training Practice)
  • M406 HE round
  • The M433 HEDP (High Explosive Dual Purpose) round
  • M433 round
  • M576 Buckshot round
  • M662 Illumination round
  • M992 Infrared Illumination round
  • The M531 less-lethal crowd control round (disperses tear gas)
  • M1006 less-lethal round (fires a foam rubber projectile)
  • The M1029 less-lethal round (loaded with 48 hard rubber .48 caliber balls)

Vietnam War

Used by the US Army Marines during the Vietnam War, M79 was effective against the Viet Cong bunkers and fortified structures. However, its single-shot capabilities were far from impressive.

M79 saw its first combat use during the Vietnam War. There were a lot of newly-introduced US weapons, like the M16. However, the M79 stood out with its reliability, effectiveness, and ability to take down enemies. It allowed the US and South Vietnamese forces to outpace Viet Cong’s commando mortars, rifle grenades, recoilless rifles, and rocket launchers. These weapons were cumbersome and rendered useless in the thick Vietnamese jungles and forests.

With that, the M79 became one of the most critical and influential weapons for the Army of the Republic of Vietnam and its allies. Since it was the first of its kind, its effectiveness justified the importance of grenade launchers. As a result, it is now a weapon used by almost all the military forces worldwide. Some countries that use the grenade launcher are Australia, Brazil, CambodiaSouth Korea, Spain, Taiwan, Thailand, Turkey, the United States, Vietnam, and Yemen.

In the US, most of the M79s have been phased out after it was replaced by the M203 (more about it later). Although, they are still being issued and used occasionally, a proof of their excellent performance despite their age.

Pros and Cons

Like any other weapon, there are things to love and hate about the M79. First, it was just like a shotgun, so using the gun was straightforward. Its high-low propulsion system reduced recoil and enabled users to launch a grenade at up to 400 yards, farther than a hand grenade. The shooters could also accurately aim at their target using the rifled barrel.

That meant the troops using the M79 would need a backup weapon. In addition, it was single-shot and had to be reloaded manually. This limited its ability to maintain a constant volume and rate of fire during combat.

Irish soldier with a Steyr AUG with a short-barreled M203 grenade launcher.

In 1971, the M79 was replaced by the M203 underslung launcher, which used the standard M16 rifle instead. Even so, some fans in the US Special Forces still prefer it due to its greater accuracy than the new M203.