I competed long ago in LRBR with a 6.5 x 284 and now am getting ready to compete in F class open. I noted loaded ammo is "out" beyond .04. I also see I had a few resizing dies, almost certainly to fix this problem and I know I never did. I have a concentricity gauge with a 1/10,000's dial so it really "moves" when I rotate my ammo.

I have built a walnut block jig with four different bullets size holes reamed into it. These holes will allow me to place the bullet from loaded ammo tightly into these holes, and work the case so that the loaded round is as concentric as possible. I have tried this with some .244 ammo and was able to get them all concentric. 1. I am amazed that with a Wilson straight line seater, this ammo would be that far off in the first place. 2. Although I managed to make the loaded cases more concentric there seemed to be no rhyme or reason as to how I went about it, to this point. It mostly was blind luck.
I would like to make this process as efficient as possible. If you have a succesful process I would really like to read about it. I know it would take time and a "feel" to develop a consistent method. Thanks