One in the Chamber is an MW2 party mode where players have three lives but only one bullet in their pistol.
If you get an elimination with your single bullet, you will be granted another. However, if you miss your target and have no ammo left, you must get a melee kill to receive a bullet.
Each game of One in the Chamber will last until only one player stands alive, as the others have lost all three lives. However, the winner is the player who has gained the most score from kills throughout the match.
This mode is a free-for-all format meaning that it is every player for themselves.
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How to Play One in the Chamber in MW2
To play All or Nothing in Modern Warfare 2:
- Launch Modern Warfare 2.
- If a pop-up for the Message of the Day appears, click Skip to close it.
- Go to the What’s Hot tab and look for One in the Chamber. If it’s listed, select it to start searching for a match.
- If One in the Chamber is not listed, go to the Games tab and select MW2. Then, browse the Featured category until you find Party Modes.
- This playlist is a moshpit of All or Nothing, Gun Game, Infected, and One in the Chamber, so getting the mode you want is not guaranteed.
- Select the mode and begin your search for a match.

If you have done everything suggested and cannot locate the mode, Infinity Ward has likely taken it off the playlist cycle.
Unfortunately, you must set up a private match to play with your friends since the mode is only available for a free-for-all.
How to Play One in the Chamber in Modern Warfare 2 Private Match
To access One in the Chamber mode in Modern Warfare 2 for a private match, follow these instructions:
- Launch Modern Warfare 2 and close the Message of the Day.
- Enter the game by selecting it from the Games list on the main page.
- Go to the Multiplayer tab and choose the Private Match option.
- Click on Create Private Match to start setting up your match.
- Look for the Alternate Modes option and scroll down until you find One in the Chamber mode, then select it to enable it for your match.

How to Win in One in the Chamber MW2 Game Mode
To win in One in the Chamber, you must become the player with the most points from getting eliminations and surviving.
This makes it possible for a player to win the match without being one of the last players standing. Players will achieve 100 points for each kill and 10 points every time they are alive when someone loses all three lives.
Check out all the other MW2 party game options that are available in the game: