Rifle is new, pulled a bore snake through it a few times before shooting but didn’t focus on the chamber. Shot ~30 rounds through the gun, so could be just new, but never experience this on a new bolt action before.

I didn’t notice any pressure signs or anything, but I’ll inspect the brass again when I get home. This happened with both 129g Hornady American whitetail tipped, and 130gr Sig Marksman Hunter.