M79 Grenade Launcher

M79 Grenade Launcher

The M79 40mm Grenade Launcher was the primary grenade launcher of the US during Vietnam. The weapon was introduced just prior to the outbreak of the war, only to be replaced before the war was over, by the M203 40mm grenade launcher. The weapon was a single shot, break-open, breach-loading system with a wood stock.

The M79 was delivered to the Army in 1961 and was used in Vietnam primarily as a close support weapon. Its simplicity and effectiveness made it a favorite with Ranger Teams. The M79 was also known as the “blooper” because of the distinct sound it made when firing. Operating the M79 is similar to using a break-open double barrel shotgun. A locking latch is pushed to the right and the barrel is pushed down, breaking it open and making it ready to load. It’s a single shot weapon that can be fired from a variety of positions such as shoulder, hip, or with the butt on the ground.

The M79 fires HE rounds, Buckshot, Smoke, CS, and Flares. The rear sight is adjustable and graduated for ranges up to four hundred meters for area targets. An experienced grenadier can accurately engage point targets up to two hundred meters. The M79 was replaced with an integrated grenade launcher, the M203.

Primary Function Grenade Launcher
Manufacturer Department of US Army
Caliber 40mm
Length 29 in
Weight 6 lbs (unloaded)
Max Effective Range
Area Targets
Point Targets 350 – 400 m
150 – 200 m
Operation Manually Breech Loaded
Muzzle velocity 76 m/sec
Sights Front – protected blade
Rear – adjustable leaf
Ammunition Various cased projectiles
P/75 Ranger Terry Roderick on patrol near the Ben Hai River, Demilitarized Zone, South Vietnam, 1970. During the Vietnam War, each LRP/Ranger team going out on patrol usually brought the M79 as secondary weapon and was used to fulfill several roles. It was effective for the point man to use with a buckshot round, the limitation being that if contact was made, only was shot could be made before having to reload. The M79 was also used with smoke grenades to mark targets for close air support and with teargas to break contact with the enemy. When using High-explosive rounds, the vegetation limited it’s effectiveness due to the short range engagements that were typical during the Vietnam War. For short range situations, hand grenades were usually preferred as they could be used without carrying an extra weapon and their fragmentation effect was more effective than a 40mm round.