I have my usual voodoo that I use to clean my SS AR barrels.  I have just used a product that will be added to my cleaning sequence.  The current process is Hoppe's BoreGel, Hoppe's Gun Cleaner, Gunslick CopperKlenz, and SLIP 2000.  Each cleaner gets a couple of wet patches followed by a dry patch.  This leaves the bore amazingly clean......until I shoved some Copper Terminator down the tube.

Even in my "clean" barrels, blue-green and copper particles, NOT coloration or staining, were removed from the bore.  Nothing is left but clean steel.  This stuff is INCREDIBLE on copper.  It won't replace the CopperKlenz(it does a good job removing crap that Hoppe's Bore Gel doesn't get), but I am now a big fan of the Copper Terminator.

If you like your SS service rifle barrels clean, I fully recommend this stuff.

Now for that borescope....