Load chapter 6, checkpoint Von Klemt's Kitchen. At some point you will enter a room with 2 normal enemies and one ape smashing throught the wall. Pick up the Ape Spine (to the right if you enter the room) and start hitting the regular enemies. Most of the time the ape will interfere and the weapon will break before you can kill the second guy. No harm done. Jump over the ledge and keep using this strategy untill the achievement pops up.