Hello, I'm new to this forum but I did however found the slingshot channel on YouTube a few days ago and it's really funny to watch all the creations Jörg makes. I was getting a little bit inspired of this and I did search in some old supplies and found an old pen shooting rubber band powered gun. I built it a couple years ago and it still works pretty well. It's made to look a bit like the m1a1 Tommy gun. It can barely peirce corrugated fiberboard with a pen and it's really funny to shoot with it. Now I'm going to reconstruct this gun and see if I can make it fire pens that can pierce "wellpapp".