A rifle of mass \(M\) is suspended from a ceiling by two long, light vertical cords and loaded with a bullet of mass \(m\). When the rifle is fired, high-pressure gas from the ignited gunpowder exerts a horizontal force that accelerates the bullet down the barrel of length \(L\) and pushes backward on the rifle. Friction and external horizontal forces are negligible, and the bullet exits the barrel before the suspension cords deviate noticeably from the vertical. Which of the following correctly pairs the fraction of the total kinetic energy acquired by the bullet, \(\dfrac{K_{\text{bullet}}}{K_{\text{total}}}\), with the physical reason that the work done by the gas on the bullet exceeds the work done on the rifle?