Talked to a younger kid who was cleaning his muzzleloader during the hunt. He was running his metal rod up and down the barrel without thought about wear on the crown. I told him about this quick trick using only a spare patch. You simply wrap the patch loosely around the rod, then insert half the patch into the barrel and hold the patch steady while the rod slips through it. This avoids contact and wear of the rod against the barrel crown.
-DallanC