One in the Chamber is a game mode in Call of Duty: Black Ops. One in the Chamber consists of 6 players competing in a free-for-all style game with a twist: each player starts off with a pistol with only one round. All players use an M1911 .45.
It is similar to GoldenEye's Golden Gun mode, as any hit with a bullet results in a kill. Upon discharging their bullet, a player is left with only the knife as a means of killing. Players will regain their bullet when they respawn.
Toward the end of the match when only two players remain, after 30 seconds, A spy plane will appear to show both players on the radar, as a way to possibly prevent a long match. Players can also earn a Spy Plane by getting a 3 killstreak.
The winners of One in the Chamber are the players with the highest scores. Kills earn 100 points, while survivor bonuses (staying alive for a set period of time) net 10 points. While it feels like a last man standing setup, it's technically possible to win the game without being one of the last three alive.
thumb|left|300px|High Roller One In The Chamber thumb|300px|right|One in the chamber being played (successfully)
thumb|300px|left|OIC on CrisisTemplate:Wager Mode