Give the patch 30 trips back and forth. There's no reason for this particular number. You can make it 20, or 40, or 37. Some bores will clean up with one patch. Most will not, and this is where people go wrong with J-B, whose essential ingredient is elbow grease, which you have to supply. Most of my rifles take three J-B patches with a Kroil patch in between.
The patches will come out black, or dark gray, with black streaks from the lands. You don't clean until this stops, because it never will. All you want is the copper gone, and to see if it is, get all the J-B out with Shooter's Choice and leave the bore wet for at least 2 hours. At the end of this time run another S-C patch through and see it there's green or blue on it. If there is, you can do one of two things: Keep up the S-C treatment, which usually takes a while, or go back to the J-B, which is much quicker.