Instructions
Play the online multiplayer version of "Call of Duty 4." The golden guns are only unlocked in this mode.
Reach Level 55 to unlock the golden Desert Eagle. Remember, you will lose this weapon, along with any other unlockables, if you choose to use Prestige Mode.
Check your challenges in your barracks. For each type of weapon, there will be a list of challenges. Usually they can be completed by getting 150 kills with a particular weapon, or by getting 150 headshots with the weapon.
Unlock the golden AK-47 assault rifle by completing all of the Assault challenges. This includes completing all the challenges for the other weapons under the assault rifle class. The golden weapon becomes an option when you choose the finish in the "Create a Class" menu.
Complete all the SMG challenges to unlock the golden Mini-Uzi submachine gun
Unlock the golden M60E4 light machine gun by completing all the LMG challenges.
Finish all the Shotgun challenges to unlock the golden M1014 shotgun.
Master each Sniper challenge to unlock the golden Dragunov sniper rifle.