Bore tech's spiral shotgun brushes are unique, innovative, and effective. The tornado style looped bristles are made from barrel safe phosphorous bronze and offer unsurpassed cleaning without any damaging side effects. These brushes offer an extended life span over standard wire bristle brushes and work great on stubborn plastic fouling. Bore tech's spiral shotgun brushes are unique, innovative, and effective. The tornado style looped bristles are made from barrel safe phosphorous bronze and offer unsurpassed cleaning without any damaging side effects. These brushes offer an extended life span over standard wire bristle brushes and work great on stubborn plastic fouling.