This glitch is fast and simple. Here's what you will need.
1. Assault rifle with grenade launcher, masterkey, flamethrower. (any)
3. Crossbow/any other primary gun.
4. Tac Insertion (recommended)
5. One other class without your gun you want to make golden.
1. Set down your tac insertion.
2. Switch to your secondary gun. ex: Crossbow
3. Switch to your noobtube etc.
4. Throw your Semtex down and kill yourself.
5. When you die quickly switch classes to something different.
6. Pick up your golden crossbow/other gun. (Doesn't work with secondaries except crossbow.)
to let you no this is what happens
When you die, it make the gun you dropped golden. Then you can pick it up and use it golden.