Quote Originally Posted by barrel-nut View Post
Does your neck tension vary much? I have Forster Micrometer seaters too, and it seems that if the bullet is hard to seat, as in a lot of neck tension, that my lengths to ogive will vary slightly. Enough to show up on the runout gauge as 82 pointed out. I've often wondered about this too. Could it be the seater stem flexing slightly under load? That's all that makes sense to me. FWIW, my Redding Micrometer seater does the same thing in my .308. I wonder if the micrometer seaters have thinner stems, making them more prone to flexing? Total guess there.
Excellant thought, thanks. I just checked the neck tension on the 5 rounds, they're all the same at .002". But, that's AFTER playing with the die to get the CBTO the same on all of them. I'll have to load some more and check the neck tensions BEFORE adjusting the lengths to determine if there's an issue there. Thanks for the thought!

FWIW...I just re-read the set up instructions for the die. It says to seat them long, measure the CBTO, then re-seat as necessary. That's what I've been doing, but measuring EVERY round....twice....is a PITA.