So I found out a nice little gimmick to move fast. Jump and while in midair, hold crouch. It will make you slide, and once the slide is about to end, jump again and repeat. You can slide unlimited times back to back, and I've found this to be a very good rushing tactic. And if you run the blast suppressor perk, you don't need dead silence.

This works in zombies AND multiplayer, untested in campaign. And only tested on Xbox One. Hope y'all get it to work!