T-17 Foaming Bore Cleaner from Thompson/Center Arms effectively cleans and neutralizes the harmful fouling in the bore from black powder and black powder substitutes. It also helps to remove plastic, copper, and lead deposits that could affect the accuracy of a rifle. The foam penetrates even the most caked-on fouling and eliminates the need to brush the barrel. Spray T-17 into the barrel and let stand for one hour while the foaming agent does all the work. A micro-thin layer of protectant is left in the bore to prevent rust and corrosion.