Yes that is a common mistake that has been proliferated by that show Myth Busters. Any mass with speed has more energy on impact. You don't actually think you are on the receiving end of 11,000ft#'s of energy when you shoot a .50 BMG do you? If you were, well, it would only be once. Look at the slow motion films of deer getting hit by a 12 gauge slug from around 70 yards out. Damn near folds the deer in half. And if you are wearing body armor, getting hit by a 12 gauge slug will damn sure knock you off your feet as well as break some ribs.