Thread: Oxidized Copper?

Cleaned my gun the other day before finalising my load using 110g Barnes. Fired 14 rounds then pulled it out today(48hrs) to scope the barrel and saw a bit of this through it. I'm guessing it's oxidized copper owing to the colour....anyone share some tips/advice. Is it just a symptom of Barnes shedding a bit as they go down the tube??? This bore scope will be the death of me as a couple of members have already said.