From a physics standpoint, there are two parts to gun recoil. There is the part where a 180 grain bullet is heading down a 24" barrel at 3000 fps, and driving an 8.7 lb. rifle to the rear ata calculated counter-reaction. Regular physics stuff. And then there is part B: when the bullet breaks its seal at the muzzle and creates a jet engine effect from the gasses exiting the barrel behind the bullet. Part B might be close to half of what your shoulder feels, and is the part of recoil that a muzzle brake serves to mitigate. It is also why the WSM calibers seem to kick less - they use less powder to develop the speed in their short, fat case; and the pressure curve of the expanding gasses is steeper - causing a lower pressure "jet engine effect" when the bullet leaves the muzzle.