The "Patriot" is recommended for removing soft and light scale deposits in straight, ferrous and nonferrous internally enhanced tubes. The large diameter end of this brush cleans into the grooves while its small diameter end cleans the lands of the tube's rifling.

ENN-062 - For tubes 5/8" (15.9mm) I.D. 
ENN-090 - For tubes 15/16" (23.8mm) I.D.