If you have it on Xbox 360 or PS3 just play online and keep doing online matches till you get to level 4. You get points when you kill someone or send in air strike or helicopter. Air strike is 3 kill streak and I think helicopter is 5 kill streak. If you have been leveled up in the middle of a match online It will say You've been promoted! E.g: Yo've been promoted Gunnery sergernt 1.
You play games of multiplayer to rank up and unlock the challenges. You must then complete the given objectives to complete the challenge e.g. Fall 30ft to your death.
First Level Up Get A New Weapon Go To Barracks Go To Challenges Then You Select which class and you can see every challenge there is.
In Call of Duty 4: Modern Warfare, the M14 rifle is unlocked at Level 46 in multiplayer.
15+ i think
level 4
Level 38, Lt. Colonel 1
depends if you are refering to live or what
Kill the boss in the last level.
You have to get to level 4.
There is none
by killing enemies, if your talking about online
get to level 55
Yes.
By simply selecting the mission you want on Mission Select...