I just got back from the range and cleaning my Glock, I noticed there were marks on the inside of the barrel that would not get cleaned off. I know Glocks can go to hell and back without needing any cleaning but is this corosion happening inside the barrel? Also, on the slide where the barrel protrudes from the front of the slide there are ridges in the slide
. Is this normal to happen? It's only on the top contact where the barrel sticks out from.
Thanks for any advice