How's this for some crazy intense and risky training: Students wear body armor and their instructor shoots live FMJ full power rounds into their torsos while the students draw, aim at a target next to the instructor, and shoot live ammo back right past the instructor, right after taking multiple hits. Note the total lack of "knockdown power" in the video. The student taking the hits on his body armor isn't visibly pushed back at all. He's rock-solid steady on his feet as he responds. https://youtu.be/rI01qKAqYts P.S. You might want to save this video or watch it before YouTube takes it down-- they might not want to leave it up, lest some fools imitate it, kill somebody, and then sue them for hosting the video. Post-P.S. Notice the instructor stops shooting before the student draws-- that's probably so the instructor doesn't shoot the student's arms, as his arms will be holding the gun in front of his own upper chest.