If that data is really from Chuck Hawk's website, he needs a new calculator. For equal gun and bullet weight, recoil energy behaves like muzzle energy.
Edit: Played with the calculators, the reason for the difference is that the 7-08 case assumes 40 gr powder, the 280 60 gr. In reality the loads are 48 and 56, which takes the difference in recoil down to about 10%.
F 135 - the right choice
Last edited by mapsjanhere; November 5, 2012 at 04:32 PM.