M-79 40mm grenade launcher Manufactured by Colt

For close range fighting the Army came up with two types of M79 rounds. The first was a flechette round which housed approx 45 small darts in a plastic casing, these rounds were issued on an experimental basis. Later this round was replaced by the M-576 buckshot round. This round contained twenty-seven 00 buckshot which on firing was carried down the barrel in a 40mm plastic sabot, which slowed down in flight so the pellets could travel in their forward direction un-aided. The M79 could also fire smoke grenades, CS gas, and flares.

The M79 had a large flip up sight situated half way down the barrel, with a basic leaf foresight fixed at the end of the barrel. The rear sight was calibrated up to 375 meters in 25 meter intervals. In the hands of a good experienced Grenadier the M79 was highly accurate up to 200 meters. Later in the war the M79 was superseded by the M203 40mm launcher which was fixed beneath the foregrip of the M16 rifle.