Hoppe's BR916 No. 9 Bench Rest Gun Cleaning Solvent, Liquid, Pint Size

Got a copper problem? Hoppe's Bench Rest copper cleaner can fix it. Shooting rounds down your barrel causes copper fouling where the jacket of the bullet meets the grooves. Hoppe's cleaner removes the residue restoring your barrel back to bare steel. As copper builds up, it can change the velocity of your rounds causing issues and carbon to build up.