Watch this new edit instead, which has a full-speed ending:    • Launching my 1,000lb Medieval Trebuch...  

Update, April 2020: I realize the slow-motion at the end is not ideal. There are full-speed clips and more angles of this machine in action in the sequel video:    • Medieval Trebuchet Launches Bowling B...  

Approximately 1,000lbs in the counterweight box, in the form of (20) 50-lb sandbags, plus whatever the box weighs empty (later confirmed to be 465 lbs). Launched a 16-lb bowling ball 540 feet. The shot went high -- I'm still working on tuning with the wooden horn and the netted sling. Loading the machine is a LOT of work, and it's scary by yourself. I don't think I will do it solo again, and definitely not at any higher weights. The machine is ready to be tested at higher weights.