You can do this achievement through your campaign game play. But If you want to farm this achievement quickly. I recommend you doing this on mission 8.
At the start of a mission eight, There is four enemies. Kill the nearest one, Put the Bobby trap on him, Threw a bottle to the center of the yard. And you can wait enemies near the traps. Before it exploded. Save game, explode, then load. Repeat this progress. You can get this Achievement in less than 10 minutes.
Here is the video link I made for clear. Hope this is helpful.