While playing around with the Valkyrie Rocket Glitch found by "redshadow95" and oX Xenomorph Xo" I was randomly hitting buttons when my gun disappeared.

I played around with it so heres the TUT: First you need the valkyrie rockets (either from the killstreak or from the care package), then a camera spike(this is what i used)

after you have purchased both of these and gotten them in game all you need to do is pull out your Valkyrie rockets (right on the D-pad)
and rapidly hit UP RIGHT RIGHT and then you should be holding nothing in your hand but to others you appear to be holding a knife as a gun. if any one can confirm this or post a video it would be greatly appreciated.

As always if this topic helped then thank it or +rep.