Ditto, chamber brush and CLP to clean the chamber to start with by hand.

Next, post a photo of the chamber conditions with good lighting so we can see the condition of the chamber walls.  
They should be smooth as a babies ass, and not reamer ridge/grooved to hell instead.

And yes, if you did not clean the chamber with a chamber brush and CLP before the rifle was fired, the case do look kind of normal for that.  The rig has storage grease, assembly lube with some debris in it, and this all has to be cleaned away before the rifle is first fired.

Double post

If the marks are after the chamber has been correctly cleaned a "chamber brush" and CLP to get all the assembly lube and  assembly debries out of not only the chamber, but the action as well, then you have a problem with the chamber wall condition.

If all you did was just lube the rifle and run it with the assembly debris still in the action/chamber when the rifle was first fired, then the chamber could be fine, and its your cleaning skills that suck instead.


So again, clean the chamber with a chamber brush and CLP, use patches to get all the lube out, then post a photo of the chamber conditions.
From what I am seeing on the  spent brass for the most part (some rings that are question on chamber conditions), it's looks to be debris in the chamber from it not being correctly cleaned before the rifle was run live to begin with.