Thanks for all of the help everyone.

To those who commented with the different types of cleaning products-I built an electronic barrel cleaner. With this electronic cleaner, all I have to do is set it up and let it run then swab out the loose stuff when it is finished. At this point, after using the electronic cleaner, it takes me just 2 passes with a patch & Hoppes #9 just to push out the gook, and then a clean dry patch to soak up the remaining solvent, and then a final patch with just a little oil for the now bare-steel bore as a rust preventative. That is the entire cleaning regimen. No more scrubbing.

Now that this barrel is down to bare steel, I'll take it back to the range to shoot it to see if the accuracy has been affected. My guess is that if anything has changed, it will correct itself pretty quickly with that sand-paper bore shredding the bullets as they pass.

I forgot to mention it in my original post, but this gun is a .243 w/26" varmint contour barrel. In looking at the action with the bolt removed, even the inside of the action is very roughly machined.