This is an AMT Hardballer barrel. At first glance I thought it was lead in the barrel…Then I realized it was only in the rifling lands/hills, nothing in the grooves/valleys….. very strange. Well, I tried to get rid of the lead but couldn’t. Bronze brush, pod cleaning scrub pad, Lewis Lead removal (just the fabric, around cleaning brush) with some Hopes 9… even 1000 grit sandpaper.. Nothing. I was very gentle when trying to remove, as this is a friend’s barrel, not mine. I even tried a dentist pick ..nada. I then took pics for closer inspection and realized this was not lead in the lands. I believe it is abrasion. Appreciate your comments.