Call of Duty 4
The M4 Carbine is a standard U.S Army rifle, and is used a lot in single player (both main characters use variants of it), and unlocked in mulitplayer at Rank 10. It is regarded one of the best guns on the game by many due to it's low recoil and high fire rate. It's only real con is that it's damage output is fairly low, so in multiplayer Stopping Power is recommended.
 Primary Attributes
Fire Rate: 7/10
You can unlock a series of attachments for the M4, which are unlocked at 25 kills, 75 kills and 150 kills. These are:
Grenade Launcher: Unlocked with the weapon
Red Dot Sight: 25 kills
Silencer: 75 kills
ACOG Scope: 150 kills
Apart from these attachments, you can also unlock camoflages for the M4. They are unlocked getting a certain amount of headshots.
Digital: Unlocked at 25 headshots
Blue Tiger: Unlocked at 75 headshots
Red Tiger: Unlocked at 150 headshots
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