Humphry`s Brass Jag .38 & 9mm and loops are just fancy words for the little attachment that goes on the end of a cleaning rod. All these parts do is hold a cleaning patch on the cleaning rod while you push it through the bore. A jag has a small point on the end. Stab the middle of a cleaning patch, and push it through the barrel. The point keeps the patch in place while you push it through.