Hello, I recently shot my first .223 reloads through a new upper I recently purchased. It was the second AR Chrome Lined barrel that I have shot and I shot them regularly with my M4 in the infantry. The cases after being fired were covered in what looks like marks from a rough metal finish in the chamber. I have never seen brass expended from a rifle that looks like this whether manual action or semi auto and I have shot, M14, LR308, RRA LAR-15 with Chrome bore and LAR-15 w/o chrome bore as well as numerous military M4, M16, M249 and M240. I haven't encountered it while sifting through military range brass either from all the rifles firing on hand that day. Has anyone seen the type of damage to cases exhibited by this chamber. The only description I can make is that it is rather porous and has a bit of a rough texture to it. Most expended AR brass I am accustomed to has the signature indents from the brass deflector and star chamber. These had those indents plus this porous damage. The loads I shot are minimum charge (10% from max) and was curious if this chamber condition would press out as I raise pressures and break in barrel? Picture attached. Headspace for cases was set with Dillon .223 headspace gauge and I resized with a RCBS small base die. Dimensionally, I did not see any shortcomings in the headspace for the cases or body dimensions as measured before shooting that would have caused issues feeding. I experienced no malfunctions. Headspace and case dimensions for reloads were same as sampled factory Gold Medal match, Lake city and Hornady match prior to shooting.