This achievement, along with 13 others, can be knocked out easily at the first encounter with human enemies in the Lost Tunnel mission. Simply keep reloading the checkpoint if you wish to get this plethora of achievements out of the way. I realize that a lot of them, the weapon kills ones specifically, will come easily when doing your Spartan mode playthrough, but I like to get easy stuff like this out of the way so that I can focus on collectibles and achievements that require a full playthrough or specific areas to obtain. The video below shows this checkpoint farming in action, unlocking most of these achievements. Although I accidentally popped Slice & Dice and Tank before filming them for the video, Tank will come without trying and Slice & Dice is no different than the others. Hope you enjoy!