I had to do a project for school where I had to make a catapult that would throw water balloons into a target. I thought about making a ballista for that but it would have been to complicated. School ended for me on Thursday and I finally found enough time to build a smaller version of the ballista this is my first time building one and it has been quite successful besides its range of about 3.5 feet.
Step 1: Version 2
I had some trouble with the first design like the bolt slipping and the string not hitting the bolt so I made a few modifications.