They are using ammo that meets the Power Factor rules
. The power factor of a firearm is calculated using the formula of Bullet Weight (grains) times Velocity (feet/second) divided by 1000.
A lot of what is causing the recoil to look light
, is the strong grip they are using.
For example I backed down from 22 grains of H-110 to 21 grains of H-110 for use with the 210 grain Gold Dot bullet in my Model 58. I also made a conscious effort to utilize a strong grip. It made a big difference. Of course that is a much more powerful load than is used in competition, but still the strong grip matters very much in taming recoil.