I clean thoroughlya after each range trip. My Savage 12 was bought used, (.22-250) and the guy who sold it told me that I would need a new barrel.
I put a couple of patches soaked with KG-12 and left the gun alone for 24 hours. Brought the copper right out, and will shoot a consistent sub .5 MoA with 52 grain SMK's. I have left it alone for the time being.

With KG 12 let it sit overnight to get most of the copper out. I wouldnt bother with trying to lap the factory barrel. When it stops shooting well, swap it for an aftermarket one.