Bullet to bullet variation will often times negate any ultra-fine tuning. I load for a smoking little 222 Rem and a 308. Both times I used a spent case with a slightly crimped neck and let the 'bolt close on the chamber' tell me where everything was lengthwise. I tried ten of the bullets I was interested in shooting from a box, got the average and backed off 0.005". I was prepared to adjust from that if needed, but both rifles liked this number (after running a charge ladder, and finding a good recipe), so I just stuck with it.
