I know of one smith who has exceptional abilities to smooth and tune R700 actions to every bit the smoothness of custom actions. Leonard Baity of NC, a pistolsmith originally, had a complete grasp of inter-component timing. His actions are an example of potential achieved in a R700. He not only trued, but timed and honed all camming surfaces.
I have/had many of his 1000yd bench and hunting guns built on R700s before the plethora of Custom actions were available, his actions rival/equal most.
So, it can be done, but at a higher cost and a limited number of smiths with the abilities to tune a action to this level.