That idea of "dumping 100% of kinetic energy" into a target is a little misleading and not necessarily important.
In order to incapacitate, a bullet has to penetrate and either strike some element of the central nervous system (i.e., the brain or the spinal cord) or cause incapacity through loss of blood.
There is simply not enough "kinetic energy" in for example a 9mm bullet to knock someone down - if there were, simple physics tells you that the same "punch" would be delivered to the person holding the firearm as well.
Therefore, the one and only reason for rounds such as the Glaser Safety Slug is to prevent overpenetration and striking innocent bystanders, either in an urban street environment or in a building with (typically) flimsy walls.
Suppose a bullet weighs 10 grams and a firearm weighs 1kg, and 454.5Nm of energy is expended pushing them apart. Then the bullet will be accellerated to 300m/s for a kinetic energy of 450nM, while the firearm will be accellerated to 3m/s for a kinetic energy of 4.5nM.
Although the momentum imparted to bullet and firearm will both be equal 3kg m/s, the amount of kinetic energy imparted to each will be very different.
>>There is simply not enough "kinetic energy" in for example a 9mm bullet to knock someone down<<
While I don't necessarily disagree with this, how many 9MM have you shot? I've probably run any number of thousands of rounds out of a 9mm. The Recoil is strong. Not as strong as a 44 it's still strong. I'll suggest that the recoil is stronger than most folks could forward with their fist...and I've seen people knock others down with their fist.
There's no question that a 44, or a 45 or even a 38(depending on circumstances)can punch harder, a 9mm is a good kill weapon.
Of course, my weapon of choice is a 12ga sabot hollow point. No one lives thru that...limb blowing off variety shells.