2 0 0Actions Report Solution A good mission to do this in is Shock and Awe. The Mark 19 is a grenade launcher. Which means if you can kill twenty people with this and unlock this trophy. There isn't a lot of targets overall but there are enough to get the twenty needed.
0 0 0Actions Report Solution On the level (Shock and Awe) you'll be shooting for this trophy in no time as long as you just keep shooting the enemies (maybe use your grenade launcher when you land to in case you still haven't get it yet)