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.
"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."
We may be in agreement. I understand that basically, momentum is what can knock the target over, while energy is what can tear up its insides.