I shoot cast bullets in some of my mil surps. So got pretty picky about the condition of the barrels in the rifles I have bought. With the exception of a few bought within the last ten years, most if not all the mil surps I own I have had for well over 30 years. Great barrels were easier to find back then they are now. I have a Chileanicon 1895 short rifle in 7mm caliber. The barrel is less than I would normally accept. Sat down and started scrubbing with wet patches, then a worn 30 caliber brush. I'm cheap and have been accused by the wife with all the junk I have laying around. Brush was a good tight fit in the barrel. Amazed by the powder and copper fouling that came out. Between uses I cleaned that brush with some spray carb cleaner. When done for the day would let the barrel soak over night.

Next day would wet patch the barrel to see what came out. Usually the green slime from copper fouling. Long story short it took five cleaning sessions to get that barrel free of all the powder and copper fouling. Do not use stainless steel bore brushes. They potentially do way more harm than good. I use the old Hoppe's solvent, but recently on the ASSRA forum there has been a new thread of the recently newly made Hoppe's causing problems on barrels. Butch's Bore Shine has been proven to remove powder and copper fouling on some of my barrels. don't know what the black looking stuff that your barrels have in them. Looks like bad powder fouling. Regards,Frank