It is not all that surprising then, that one of the best shooters in the world, my buddy Rob Leatham, recently posted a video (which bordered on a rant) extolling the importance of the 5th grade physical science fact: All other things being equal, a typical .45acp round delivers more energy on a target than a typical 9mm round. My own experience, experimentation and research has lead me to the conclusion that 9mm is a better choice despite its smaller diameter, lower mass and the generally lower levels of both force and momentum that it brings when compared to .40S&W and .45acp.