If you want to unlock the sweetest weapon camouflage in Call of Duty: Black Ops 2, the diamond camo, you're gonna have to put some back into it.
In order to unlock the diamond camouflage, you will need to unlock each and every camouflage option available on every gun in their respective category. Here is a list of the available camos:
- A-TACS AU
- Blue Tiger
- Ghostex: Delta 6
- Kryptek: Typhon
- Carbon Fiber
- Cherry Blossom
- Art of War
So, if you want a diamond AK-47, you will need to unlock all of the camouflage skins for every single assault rifle. Needless to say, this can take a pretty long time, so learning a trick or two for leveling up your weapons is essential. This video gives some tricks for assault rifles, LMGs, and SMGs.
Leveling up your weapon requires a player to get a ton of kills and headshots with that particular weapon. Here's a complete list of requirements for weapon leveling. Using the laser sight, and hip firing are just a few way you can beat those challenges faster.