Pictured is a 40-mm low velocity grenade that was the type used with the single-shot M79 grenade launcher and was popular in Vietnam. These grenades had a variety of colors designating the type. The blue/green was a practice grenade, gold/green was high explosive, white/green star parachute and star cluster, and gray/green with a red band was tactical CS. Late in the war the M79 launcher was replaced by the M203 launcher that was attached to the M-16.
The grenade rounds could be carried in the M79 grenade vest or the earlier bandoleer.