Since you have leading and some more gunk to remove, a small investment in Kroil is worth the outlay. It does an excellent job of getting under lead and carbon, allowing it to be brushed out of the bore. I usually run a patch wet with Kroil, put the pistol in a closed container in my garage overnight as Kroil is full of volatile chemicals I prefer not to smell, and then brush out the bore the next day. I am always amazed by how much lead and carbon Kroil loosens.