Cause of shiny ring on bolt face?

[coyoteking]

Is this a headspace issue?

There’s no dimpling or pitting or scorch marks so I don’t think it’s from gas escaping around the primer. I’ve never had any pressure signs on my brass, never a blown or leaky primer and never any problems with extraction or sticky bolt lift.

When I run my thumbnail over it I can’t feel any raised marks or indentations.

Its a Kimber hunter in 280AI. My loads are right at book max, using Nosler brass and I bump shoulders back .002” with a Redding body die.

 

[ShawnC6]

Just where the brass is contacting the bolt face when you rotate the bolt? Round is not moving around like the bolt face is.

I feel like that would wear the coating off.

 

[mulemania]

Looks to me as though it had I primer blowout in the past and has since been sand/bead blasted, when it had a primer blowout it may have made a flare on the edge of the burnt ring, causing a high spot that the cases have essentially been polishing.... just my thoughts