Quote Originally Posted by m12lrs View Post
Have you checked your loaded round on a concentricity gauge. Could be the ammo and not the chamber.

Tight freebore is a good thing. Shooting it will soon smooth out any tool marks.
from the original post:

"Measured runout, under .001". Just to make sure, I used the hornady concentricity tool to get some rounds dead on 0.000". And tried chambering them. Same deal - scuff on one side."