You get weapon XP by shooting equipment, destroying killstreaks, or killing people with your weapon or launcher. Probably somewhere above 800 kills and below the thousandth kill mark.
You need to achieve 25 (24 with hardline) gun-only kills in a row. In MW2, Your Assault killstreaks such as the Predator Missile and the AC130 counted towards the 25 kills, however in MW3, you need to get every kill with your gun/grenade/knife.
It really depends, because there is no set amount of kills to get the gold camo. You must get your weapon level to 31, which is not easy. The best way to do this is use the gun with many different attachments to get all of the challenges for the gun. This will give you a good amount of weapon XP, and much faster than using the gun with the same attachment all of the time.
A M.O.A.B is a 25 gun streak. 24 with hardline
"Colored guns" or gun camos (short for camouflages) are unlocked through normal weapon use - by getting kills or destroying enemy support and equipment.
The best mw3 gun is the L118A but that's because I like sniping.Or if you put the first one on perk 2 its the best quickscoping gun
The clan is rhvg
In MW3 you level up your gun by using it. You get xp by getting kills or destroying enemy equipment like a helicopter. If you use it enough you will unlock new attachments camouflages and other things.
RSASS sniper rifle
Either an M4A1 or M16
you have a good gun and kill everyone you see. :)
mw3 is awesome very awesome for awesome people and this stupid tf2, the gun suck, everything in tf2 is suckish. play mw3, mw3 is the best and tf2 are for noobs and losers
A gun typically is not what kills, unless we are talking about being clubbed with the stock or bayonetted. The bullet fired from the gun combined with the shooter's intent is what kills.