recoil question-part ll

This is in response to the post by saserby: I routinely compute recoil energy for my loads using a formula printed in the Lyman reloading manual. A couple of examples follow:

Two loads for a .30/06:
165 gr bullet, 2708 ft/lbs muzzle energy, 17.7 ft/lbs free recoil
180 gr bullet, 2716 ft/lbs muzzle energy, 19.3 ft/lbs free recoil

Two loads for another .30/06:
150 gr bullet, 2987 ft/lbs muzzle energy, 19.0 ft/lbs free recoil
180 gr bullet, 2991 ft/lbs muzzle energy, 22.4 ft/lbs free recoil

FWIW