Woah, just had a real cool thought...
So your in your vent, in your skrim. You and you mate are both using AKs, say. Your mates fighting, your running to him from spawn, he screams over vent that hes out of ammo. You hold F to throw your AK up to him, he catches it and kills enemy.
Of course, you might as well just jump up and kill them yourself, maybe.
Cool idea though, you got my vote.