this is kinda old, but there still hasnt been a tut on how to do it (well, i havent seen one...). There have been vids like this before, and i've heard a couple say that its just a glitch in the cod5 gaming engine...?
This is old, but the person that says that you do it with a grenade is wrong. You are thinking of CoD4. CoD5 is different because if you hold a grenade, your limbs come off. I don't think there is a specific way to do it on CoD5, only certain places where it could work. That is why there are no tuts either. I repped ya. Rep me back?