I posted a few months ago about a 7 mm mag that no matter what I did copper was always stuck to the lands. I tried Hoppes. Break free. Copper remover plus. And even the Bore shine. I let the bore shine set for 15 minutes per instructions and nothing. Saw a gunsmith yesterday having a little work done and he said leave it in all night. I put a wet patch through the barrel at 11 last night. Got up at 6 this morning and ran a brush through for about 10 strokes and a few patches and copper is gone. Put some caseys gun scrubber in to get all the bore shine out and a little ballistol after to keep from rusting. Now to see if I get my accuracy back. My old 1972 Winchester got the same treatment this morning and about 30 minutes ago it is spotless.