DO NOT USE THIS WAY. LOOK DOWN FOR MUCH EASIER WAY. THIS IS FOR ARCHIVES PURPOSES ONLY Okay, first you have to have a large machine gun with a bi pod on it. Go prone and it'll give you the option to set up the bi pod. Move foreword while holding x to set it up. Make sure you hold x until it is completely set up. Then the ammo on your screen should disappear. This glitch is known about by Treyarch but won't be fixed until the next major update. This does work, as I was just doing it now, and it's amazing.
Edit: Heres an easier way.
THIS ONLY WORKS MOUNTED ON THE GROUND BTW.
Get on the ground. Get Mounted up. Push the left analog stick foreword. Your ammo will disappear. Enjoy.
your an idiot. It wasn't made to do this. If you just set up your bipod, you will still have a limited amount of ammo. Do you even have the game? it is a GLITCH which only occurs if you are lying down and mount your bipod and then push up. You think they put that in on purpose?
im not an idiot. and i do have the game . and I DONT HAVE TO PUSH FORWARD OR ANYTHING. but now it doesnt matter cuz its patched