Unless I'm severely mistaken, this is incorrect. Muzzle energy and recoil energy have to be equal, it's a fundamental law of physics. For every action there is an equal and opposite reaction. How the recoil feels is completely dependent on how quickly the energy is transferred to your body and how it is absorbed.
The example you gave isn't quite accurate, as when you fire a gun you never actually let it accellerate and then deliver it's recoil energy in one hit. You have the stock jammed into your shoulder so that you steadily absorb the energy as it is transferred to the weapon.
Picture yourself firing a 12 guage shotgun correctly, and then repeating the shot but this time with the stock about half a foot in front of your shoulder, while loosely holding the gun. Same energy in both scenarios, but it will be delivered all at once in the second shot and would probably do some damage.
severely mistaken. For every action, there IS an equal and opposing reaction. This is the law of conservation of momentum. Energy and momentum are always conserved, but it is much easier to see where the momentum went.
In the case of energy, you start off with a chemical potential energy in the powder and zero kinetic energy. In the case of a .30-06, this would be in the neighbourhood of 20,000 joules. Roughly one third of this is transferred to the projectile, another third is held by the propellant gases (in the form of kinetic energy, as the gas is heated and thus has a high particle speed, as well as having a net velocity - out the end of the barrel), and the rest goes to heating the barrel, with a small amount being transferred to kinetic energy of the firearm itself - the recoil energy. In a hunting rifle, recoil energy would make up less than one percent of the original chemical energy. Remember that energy is a scalar quantity, while momentum is a vector, and that the cartridge contains energy, not momentum. The fact that energy is scalar means that you can't "cancel it out". The same is not true of momentum.
Now we move to momentum. It must also be conserved. We have zero momentum to begin with, and that will continue to be the case until we add some. The bullet leaves the barrel with something like 15kg*m/s of forward momentum. To cancel it out, in the simplest case (no muzzle break) we need the same amount in the opposite direction. If our firearm weighs 10kg, it will be accelerated to 1.5m/s in a direction opposing the one of the bullet leaving the muzzle. We now have zero momentum, and physics is happy. If a 90kg man was holding the gun in such a way that he absorbed the recoil, his torso would be accelerated backward to roughly 0.2m/s, something that is perfectly manageable and shouldn't result in falling.
Now, imagine if energy was conserved. I do agree that my sledgehammer analogy was inaccurate, but a more accurate one wouldn't be a whole lot more favourable to the shooter. Assuming perfect stance, the 90 kg man's torso would be accelerated to about 11m/s. If it didn't kill him, it would certainly ruin his day. Kind of like being tackled by a very large man running as fast as an olympic sprinter, but the entire impact would be concentrated on a few square inches of your shoulder.