Description: Achieve 100 Assault Rifle, 50 Pistol and 25 Marksman Rifle kills.
Note: All perk-based achievements can be obtained by re-loading the checkpoint and keeping progress. See video in description for details.
Cumulative throughout each level, the bit you'll probably do last is getting the Marksman kills. Nothing flashy in necessary as you can kill any enemy to add the points up. Area in the video is a good spot, but there are probably better ones if you find a room full of normal infantry.