Having seen the photograph previously; learning that Heath used a .416 Rem. ruined several of my fantasies about me and my 9.3X62.
I was about to ask why the rifle recoiled so hard if it was a 9.3x62...My 9.3x64 is more powerful than the 62mm version and I don't experience nearly that much recoil.
A .416 would definitely explain the bent knee and high muzzle angle.