Everything is within spec and they still don't chamber?
If factory ammo always chambers, then there is something different.
When you measured diameters of fired cases, was there any increase in diameter near the head?
While I believe it is rare, sometimes small base dies are necessary.
Also, when you say "shiny spot on top of the case", just where do you mean?
.30-06 Springfield: 100 yrs + and still going strong