During Sequence 3 Memory 4, you will learn how to craft bombs. Once you learn where to go to craft bombs, you can get this achievement whenever you want. While in the bomb inventory during crafting, just pick any of the pouches and fill in the shell, gunpowder, and effect. Then hit craft bomb at the bottom. That will count as 1. Now hit and dismantle the bomb. It will give you back your supplies. Do this over and over again, building bombs and then dismantle them. You will lose nothing by doing this. Once you think you have enough, exit out to gain your achievement.