Run one oiled patch down the bore and pull it out. Take a clean patch and smear JB evenly over the patch and push it with a .50 cleaning brush on your rod (a .50 jag will be too loose). Be consistant by going all the way down and back up to the QLA then back down. Just run 10 strokes this way and then clean it up with oiled patches then dry patches until all the JB is out. Pull the plug and push a patch all the way through then. See if the bore is shining now?