Hi, I'm writing a guide for each of the weapon achivments in dead space. Following the guides will allow you to 100% the game in two playthroughs, rather than 3 as the walkthrough says to do. You will find In the later chapters an enemy called the Guardian. Heres a link just in case you don't know what he is http://deadspace.wikia.com/wiki/Guardian
. He'll shoot out pods which are essentially lurkers that can't move and have only one tentacle. Simply shoot the tentacle for an insta kill and wait for him to pop out another. Rinse and repeat 30 times. What I find to really help is once you find a guardian, backtrack to a store and save, then sell all your guns and ammo except for the gun your doing the achievement for. Then invest all that money into ammo for that gun. Run back and once you pop the achievement go to the menu and reload your save. Also do not run too close to the guardian or the pods as they will insta kill you and have you start over. I'd like to note that it is impossible to miss any of the guardians as you need to kill them to progress but if anyone knows what chapters they actually spawn on feel free to comment.Notes that pertain to this gun:
If you are trying to 100% the game then this strategy is not advised as you should get hundreds of kills during your "one gun" playthrough.