[Atlas Sneezed]

"There is equal momentum transfer between shooter/rifle and the bullet. That is, after the shot, the center of mass and momentum of the composite system of shooter and bullet are unchanged. However, the velocity of the bullet is much greater than the velocity of the recoil."

You are heading down the wrong path here, I believe. The key is momentum, which is mass times velocity. Momemtum, not energy, is what moves a mass that is struck by another mass.

(And all this assumes that all the energy of the bullet goes to the target, without overpenetration.)

[Pearls Before Swine]

You are heading down the wrong path here, I believe. The key is momentum

No, I'm just not expressing myself clearly. The article said "energy." I agree that momentum is conserved, and as far as knockdown goes, as you point out, it is the right quantity to use.

However it is also true that the damage to the target is done by the buller's kinetic energy, and since the article used the term "energy" instead of "momentum", I thought I'd point out that the bullet winds up with most of the kinetic energy upon firing, even if the momentum from the recoil matches that of the bullet.