So I came across something in my barrel that has me stumped. Few years back I bought a complete BCM upper to throw into storage. I do pull it out every so often (2-3 times a year) to punch oil down the bore. Here is where the mystery begins; I recently acquired a bore scope and decided to have a look down all my barrels. This one in particular was absolutely ridden with what appeared to be rust, a yellowish orange-ish layer. I started brushing it out with solvent, but all my patches came out black and blue. Furthermore, with 99% of things cleaned out there does not appear to pitting. So my question to you fellows is, was my bore rusted? This picture was taken after a few brushing cycles and does not reflect what it looks like now