Introduction: Pretty Strong Paperclip Gun With a Working Trigger
All it takes is cardboard, tape, rubber-bands, paperclips, and a straw. It has a working trigger with internal gears. It might be a little tricky for an 8-year-old, and don't expect it to be done in 5 minutes. But it's actually pretty easy!
Blueprints and Instructions
Website
My invention can shoot pretty hard, so don't hurt people!