Knife to a Gunfight

Knife to a Gunfight is an achievement in Halo: Reach. It was unlocked when a player, playing as an Elite, killed five Spartan players in matchmaking.

The achievement's description states that the kills must be earned in Firefight, however the achievement could also unlocked by playing Invasion. Indeed, this was how nearly all players would have unlocked the achievement, as there were very rarely any Firefight matchmaking playlists which included the option to play as an Elite.

Following the shutdown of Xbox 360 Halo online services on January 13, 2022, this achievement is no longer attainable.

Trivia
The achievement's name refers to the phrase "Don't bring a knife to a gun fight," which means that you shouldn't enter a challenging situation without being properly prepared or equipped.