Silent movement.

Hi! I've seen a couple of times already how one can run almost like with Dead Silence but some footsteps were getting through as normal (maybe 1 in 20). Visually in 3rd person view there's nothing out of ordinary, but in 1st person view it seems like one is floating (abnormal gun movement while sprinting).
Is there any known hack/cheat/trick for this?

It all started from bolt-action rifles and WaW is the most enjoyable to me in that regard (bolt only servers).
Also there's a great server without kill streaks - that is fun too.

I'm still hoping to get an answer about silent movement. Not that I'm gonna use it. I just want to know whether it exists or is it just my imagination.