Hobbies And Interests
First Mission
The best opportunity to unlock the Frag Master achievement occurs on your very first mission, "Operation 40." Early in the stage, take cover behind a wall of sandbags and look for a truck parked near two large oil barrels. Enemy fighters collect near the barrels to return fire on your position. Lob your frag grenade at the two oil barrels, which will result in a massive explosion that eliminates at least five enemies. Even though the oil contributes to the explosion, you still get credit for frag kills, winning you the Frag Master trophy.
Fifth Mission
During Mission Five, "S.O.G.," you must defend the town of Khe Sanh in South Vietnam. Look for the area in which the North Vietnamese Army soldiers pour out from the tunnels in the background. Targeting the stream of soldiers with a frag grenade can often record five kills, unlocking the Frag Master.
Sixth Mission
On Mission Six, "The Defector," you can use a trick to earn Frag Master so long as you're playing on Recruit level. The mission opens in a war-ravaged office building crawling with enemy soldiers. Shoot your way through the first two rooms to encounter a gathering group of fighters. If you try to toss your frag grenade, the enemies scatter to limit potential kills. Instead, pull the pin on your frag grenade and then run into the middle of the enemies without shooting them. The enemies converge to kill you, but your frag grenade beats them to it, blowing you up along with the necessary five opponents to earn the Frag Master trophy. And even though you die, you'll still have the Frag Master when you resume the game.
Zombies
If you're playing the game in Zombie mode, you and a teammate can work together for an easy Frag Master. Shoot the legs off five zombies and position your partner as bait. When the zombies clump together in crawling towards your partner, toss your frag grenade to collect the necessary five kills.
Multiplayer
The easiest Frag Master technique of all occurs during online multiplayer games, although it requires plenty of help from your friends. Get five of your pals to play on the other team and have them huddle together. One simple grenade toss wins you a cheap Frag Master.