Easiest way to do this (besides being really good) is Gib Fest mutation.
Be warned, it will still not be easy. You're still going to need to be very alert of where enemies are. I would recommend playing with Full Captions on, this tells you when a special infected shows up and dies. With the M16 this mode becomes a lot easier, just don't get over confident, and remember tanks are still a threat. Witches will also one-shot you, so try to avoid them at all costs, if you can't try your best to attack from far away first.