I don't think there is an exact number :/ You gotta take weapon and attachment challenges in to consideration as well.

That's a pretty good guess SniperRed. I've got the gold camo on quite a few guns now. I regularly do most challenges on weapons and have achieved it in right around 1000 kills. It's usually within a 100 kills +or-.

Usually I complete only few attachment challenges, I'd say it takes about 1000 - 1300 kills with the weapon unless you complete every single attachment challenge for it.

yesterday, i jumped from level 3 immediately to 9 by just two kills with dragunow, as i finished the "kill 1000 enemies with this gun"-challenge, so, it shows that there is no clear number, as it also depends much on challenges you master with them, attachements, kills, headshots, veteran-kill-challenges...

The 1000 kill mark is about right. I've stopped prestiging so have been getting the gold guns for a while now, I checked a few guns I stopped using after getting gold and here's is what I found - Type95 = 1083, G36c = 1037, MK14 = 1015, AK47 = 1046, MP5, 987, L118A = 841 (snipers take because of one shot kills, I think). The rest of my gold guns are hovering around the 1200-1400 mark now except the MP7 and ACR which are 2500+ a piece. .

About 12?

800

If your prestiged about 500 to 600 kills including attachments not prestiged 750 to 800 i think pm9 was my first gold gun then now ima on a road for every gold gun working on the mp7

800 kills excluding challenges no idea with challenges

What purpose does the Camo have?  Does Gold Camo make your weapon more distructive?  I never see any difference with or without Camo.