I was watching a Darrel Holland course where he was using an Arbor press in conjunction with a barrel block that was made with the exact same reamer and dimensions of his rifle's chamber. He could use the arbor press to seat his bullet and then check against the barrel block, trying to get the bullet set in the same place every time (just touching the lands).

Once he had the bullet seat adjusted, he could fly through the loads and be at exactly the same set depth every time while reducing run out that could occur on a normal press bullet seat die. This would allow him to refrain from having to use a concentricity roller to provide the same bullet position every time. In his explanation; same bullet depth and no run out equals amazing consistency and precision.

He also uses a brass mill to turn his necks as well. Now I'm sure these are above and beyond techniques for a lot of people, but if we're going through the trouble of building rifles and hand loading ammo, why not? I'm at least down to experiment with it to see what happens. If nothing else, I'm just learning one more thing about the way my rifles shoot.