That all adds up to equal penetration and that won't throw a person to the floor. Life aint a John Woo movie and all the videos of rich Arabs dropping a .577 won't change that.
You believe that the bullet penetration equals the rifle movement????
If you understood simple physics (MV1 = MV2, assuming a non-elastic collision) and knew why a ballistic pendulum works the way it does, you wouldn't be wondering why the rich Arabs were dropping the rifle or what was happening at the other end.