Physics. Its real. Kinetic energy is simply a measure of the work potential of a projectile. As noted above, although part of the equation, kinetic energy in and of itself it is not a predictor of incapacitation effectiveness. Recall:
-- Bullets cannot physically knock down a person by the force of their impact.
-- Kinetic energy or momentum transfer from a projectile to tissue is not a wounding mechanism.
-- The amount of "energy" deposited or momentum transferred to a body by a projectile is not directly proportional to the amount of tissue damage and is not a measure of wounding power.
-- Wounds of vastly differing severity can be inflicted by bullets with identical kinetic energy and momentum.
What a bullet does inside the body--whether it yaws, deforms, or fragments, how deeply it penetrates, and what tissue it passes through is what determines wound severity, not KE!