I mentioned the study was using rifles and handguns later and including 458 magnum rifles. I referenced the study parameters as I faintly remembered. I now believe it was a high of 2100 fps as the upper window of when penetration would resume to take off and be added. The window was from around 1300 to 1400 fps with any bullet, not just hard cast, to the rifle velocities of 2100 fps that diminished penetration gains were being seen. It was a phenom I observed empirically. I want short range hunting like shotguns and revolvers. I am not for all out X-frame velocities. I shoot 3 inch 12 gauge not 3 1/2. I shoot open sight revolvers and keep shots inside 50 yards as a rule. So the platform is a 500 S&W shooting 500 JRH and a 460 S&W using 454 Casull. The all-out can be done but I am not going all-out because I choose not to, right now.