Clip a bag clip into the small hole, and it’s ready to fire. It’s recommended to use pliers to gently press it down (without leaving marks) so it fits tightly. By the way, does anyone like my ugly carpet? Created by AgonyEcho on Printables, reposted on Makerworld for convenience. Link:https://www.printables.com/en/model/340366-functioning-mini-toothpick-handgun-mk-16-v-3