do you read the "handloader" magazine? How about "precision shooter"? There have been several good articles on this over the years.
From what I remember these "benchrest"procedures will reduce the group size by .1 to maybe .4 MOA. There are a whole series of things that benchrest shooters do to prep the cases for the best possible accuracy.
2 things to keep in mind is what is the rifle capable of and what is the realistic accuracy needed. What kind of accuracy can YOU achieve in the varminting field?