Back when I was doing smith school we spent a bit of time learning about glazing in the chamber. Back then the big culprit was 3in1 oil. Guy would use it a lot back then. Leave it in and it would only take a shot or two to glaze like epoxy to the chamber walls. The Rem Action cleaner or Gun Scrubber dries that out well, but it's not really a chamber cleaner and doesn't do well with oil glazing.
Had a gun here a few months ago with real bad chamber glazing. I took an old 20 gauge brush, covered it with a good square patch, ran Barnes solvent on the patch and used a battery screw driver (not a drill, but a screw driver) to scrub it well. Two patches later and it was back to factory glass. Don't recommend doing that often, but works if things get glazed badly.
Most rifle guys I know run a dry patch or two through the barrel, but forget to come in with a tight patch to the chamber to remove all that dirty oil and solvent. Again, patch over an old 28 or 20 gauge brush works pretty good (I'm not much of a mop guy). No need to strip it with action cleaner. I actually try to keep action cleaner out of my chamber completely. Just run in dry by hand until the patch comes out clean. Preferably using a brass rod you can twist like a Dewey.
