Whallop = R^2 * 1/2m
Where :
R= free recoil of the rifle (Lb-ft/s)
m= mass of projectile (grains)
The mass of the projectile is important but nowhere near as much as the recoil. Recoil is squared because the bullet gains energy once it leaves the muzzle. This is also known as the Authority Factor.
The full equation uses TOF to reduce the whallop calculated but is largely disregarded inside of 362 yards. Use of a muzzle device like a brake or suppressor can shift this distance, but once the Authority Factor is included, the shift is not really observable in the field.