Help please identify and correct? Possible result of neglect

[emulzhn]

Saw this tonight while cleaning her over. shot last about 4 mos now. Usually meticulous re cleaning with Hoppes 9. Last outing was in August after sending about 20 rounds. Did not swab after and sat in safe without dehumidifying agents. I was initially drawn to the exterior pitting, which I rubbed mildly with a surgical blade… but noticed that it was beyond just the surface. But on a closer observation, I see the copper colored irregularly shaped (what appears to be oxidation) or whatever it may be in the rifling. I don’t see anywhere else but then I don’t have a bore scope. HELP…
I almost sold my left nut for this MPA and horribly bothered. Thanks in advance All…

 

[m1match]

It looks like corrosion but until you swab it out with solvent and a penetrating oil like Eezox or Kroil, it's hard to know for certain. However, I've seen barrels that looked bad inside that shot very well, so I'd probably clean it with solvent then go shoot it.

Rust and BT Eliminator/Carbon Remover

In this megathread, @Frank Green talked a little about having his barrels coming back for issues where BT products might have something to do with it. https://www.snipershide.com/shooting/threads/for-the-love-of-god-gi-joe-and-john-wayne-cleaning-and-abrasive-cleaners.7183723/ Well I did have...

www.snipershide.com

I had corrosion in 3 barrels per this thread but they all still shoot just as well as before.

 

[hafejd30]

Definitely corroded