Looks like a pretty good project. I always wanted one. However, the one I wanted was like the mortar I saw at the Western National Rendezvious in Utah 20+ years ago. A guy from Nevada had a bowling ball mortar. It used a 12Ga shell full of BP and sent that bowling ball quite a ways up and out in the range. He had an eye screw with a rope attached so it was easier to retreave the ball. I just always thought it was great and wanted one.