This is my catapult I made.  It was a little messy, but this project was kind of difficult to do.  I did not think my project would work out at all because on the first test runs it didn't do too well.  I put glue on the sling part to had a little bit of weight onto it and it worked out fine actually.  My design was more of a bounce type of shot.  My numbers weren't too bad either on the 3 shots I only made it in the cup 3 times, 3 100's.