To get this achievement you need to come first in a multiplayer match on all six maps;
Majestic
Def Con
Box Car
Depth Charge
Projects
Harbour Master
I did this in a ranked match with a minimum needed of 4 players. The online side is dead so you will have to boost this. Key is that if everyone gets the same score (push backup to check), then you all get the win.
Rather than all stay on no kills, we looked to get about 10 each per round, so as to also work on the 200 kills. Just be careful as kill moves get a higher score than shooting someone. Good luck!!