Rogue Warrior

Alright guys contrary to public opinion this ones very simple to do 1v1 create a Deathmatch and choose the map Projects set the time to about 40 minutes , one person goes up to the far corner of the map where there's a wooden ramp leading up to the 3F and picks up the Dragunov Sniper Rifle and aims directly across to the far right windows , where there is a spawn point that if you put the other person over on that side they will constantly spawn there using this method you can easily get 100 kills in 20 mins even more enjoy :)

To get this quickly, get together as many people as you can for a boosting session, but you can do this in player matches with as few as two people.

Load up a match on the map Boxcars. Have the shooter go up top in the area with the wooden scaffolding. There is a blown out room at the corner of the scaffolding with a Druganov sniper rifle that respawns infinitely. Have the shooter stand out on the corner of the wooden scaffolding and everyone else run out into the open area below and around the scaffolding to be shot. Set the match length to whatever you want, but 5 minute matches will rotate everyone quickly, and 200 kills is not that many, so you should have it within a few matches if you can get enough people. If you play on Deathmatch mode, the shooter will be able to see everyone on his mini-map when they come out into the open area.

Win or lose, you will also get credit toward the achievement for playing 50 matches online.