Frag Master is a campaign achievement/trophy in Call of Duty: Black Ops. To earn it, the player must kill five enemies with a single frag grenade. Also, any kills by environmental (such as a red barrel or exploding car) explosions caused by the frag grenade count toward the five kills.
A good place to get this achievement/trophy is in the mission "Operation 40" when the player is waiting for Carlos' men, by throwing a frag grenade at the first row of enemies, as the barrel explosions will help kill all the enemies.
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