I spent several years trying to master Jack Dempseys 'step punch' as they use to call it. The trainer who taught me back in the late 50's had fought bare knuckle and had also fought Dempsey. I can tell ou that the punch is pure power if delivered correctly, but it take perfect timing in when to deliver and if you are not careful, it will pull you off balance and leave you open. If you can, get some old videos of Dempsey and play them. Dempsey was one of my all time favorite boxers. In later years at age 70, two men attempted to rob him on the street and Dempsey knocked both of them out with single punches.