interesting ejection problem

so in my 308 AR that i built, i have a weird ejection problem. only gone through about 30 rounds so it may simply be break in. but when it ejects it scratches the brass pretty badly, and at the neck the scratch is deep enough that i can feel it and see it has a bit of a gouge. my guess is the chamber sharpness is doing it as the lines are paralell and evenly spaced on each piece of brass. im not sure if that chamber sharpness just need to be worn down, or it i am having an issue with the ejection system itself. it fires perfectly fine. no misfires and its accurate as hell. this problem just left me scratching my head.

any have any ideas?

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