The Pro-Shot Cotton Bore Mop Gun Cleaning Brush is 100% cotton and manufactured with a brass core and looped end. They are manufactured of the highest quality construction possible. Pro-Shot Shotgun bore mops are wool with a brass core and looped end. Mops are especially excellent when using oil for bore lubrication because they create foaming action that helps in the lubrication process. Mops can be used for quick cleaning and bore lubrication.