Sorry to sound like an echo but shooting big bores kickers on the bench with no pressure or control of the forend results in strange placement accuracy vs a firm hold.In light recoiling rifles this technique seems to make little shoot placement effect. I assume its the bullet speed, stock configuration, and resistance to recoil involved.

I shoot with firm but not heavy foreend control off the bench or sticks.Seems to reproduce the groups noted in the field better for me.That's the ultimate similarity you wish to reproduce.