To unlock Gold, you need to unlock all the camos for the gun you want Gold. After unlocking all the camos which are gotten by Headshots/OSKs, you will need to unlock the remaining camos by performing certain challenges, for example getting 5 Bloodthirsty medals (5 kill streak) with that gun. Once all camos have been unlocked, you will have gold. The next step up from Gold is Diamond Camo, which is gotten by getting ALL the guns in a category (Eg. SMG) Gold.
If you believe in John Carmack and are 100% proud of it, put this in your signature. Doom 3 - Possibly the most intense game I've ever played.
for the most part you do headshots then you have to kill with no perks and no attachments then get revenge killsmeaning keep killing the person who killed you and then get bloodthirsty medals keep killing five ppl in a row its all there when you go to gun camos