We have 4 of the Marlin 917V rifles and we are very careful about cleaning. I feel that shoving a rod down the barrel is about the most damaging thing that you can do to a barrel. We also shoot matches so the barrels get lots of rounds through them.
First, get a GOOD one piece rod and the correct brushes, jags and patches. Avoid jointed cleaning rods like the plague! Put some wet patches down the bore. I use Butches bore shine or Hoppes #9. Butches does a better job if you can stand the stink. Run the correct brush down the bore one time with no scrubbing. Never reverse the brush direction while IN the bore. Let her sit for an hour or two then repeat. Never scrub or brush excessively and be very cautious about allowing the brush or jag joint to nick the muzzle as it exits the bore.
When the patches come out clean without any trace of green copper fouling, the bore is clean. On a new barrel, it has taken as much as three days to get the copper fouling out.
Let the chemicals do the work. Put the stuff in the bore then go do something else for a while. When you think of it, run another patch through the bore. Use as little mechanical brushing or rod movement as possible.
As the barrel gets broken in, you'll notice much less copper fouling and the bore will be much easier to clean.
Flash
