What is this stain on my PM40 barrel?

[Banshee365]

I've got a new stain on my PM40 barrel. The gun is new and has about 150-175 rounds through it. I clean my guns meticulously so this is a weird thing to happen to me. I keep a light film of gun oil all around the barrel on all my guns so it can't be corrosion. I can't feel anything at all. It seems to just be a stain, no etching or anything.

What do you guy's think?

Sorry for the different sizing. I sized them together so I'm not sure why the images ended up different sizes.

[Bawanna]

Don't recall seeing anything like that before. These barrel polish up pretty easy. I took just a little polish and a bench wheel and my barrel and chamber look like chrome. I don't know if that stain is just in the finish or deeper, almost looks like it might be deeper.

Strange.

[gb6491]

The barrels are nickel plated. By chance, did you use Hoppe's to clean it?
I ask because folks have reported that Hoppe's can affect nickel finishes. I guess other cleaning agents might also.

I doubt it will affect any thing, but, as Bawanna suggests, you might be able to polish it out. If you don't want to polish, try a little Bar Keeper's Friend on it.

You will experience operational wear in that area, so you might just want to leave it as is.

Regards,
Greg

[Banshee365]

I use Hoppes Elite/Mpro7. It's a water based strong soap solvent. I did not use Hoppes #9 anywhere on the gun. It definitely seems like something has ate into the finish. I thoroughly dry and lube the gun after each cleaning with solvent.