My latest knex gun is the Overkill. It is actually two guns in one, a turret gun and a slingshot gun. This massive gun uses an immense amount of pieces and weighs approximately 2.5lb. There are two individual handles and triggers so you can shoot which ever, the turret, or the slingshot whenever you want. This gun is probably my favorite gun I've made so far, So don't forget rate, comment, and subscribe if you want more from me. In the video i wasn't using to good of rubber bands.
Go here for instructions.
https://www.instructables.com/id/Knex-Overkill-Instructions/
