McJ Tools Pistol Bronze Bore Brush (20pack 38 Cal)The number of bristles are maximized for the caliber. Bristles are made of high quality bronze. It will not scratch the bore, but is aggressive enough to scour away lead fouling, copper fouling and power residue. The 22 to 50 caliber brush is using 8 32 threaded brass coupler. It will fit most brands of cleaning rods. Item Number: McJGS PSTL 38 20 Dimensions: 5. 87 x 3. 66 x 1. 38 inches Weight: 0. 47 lb In 1980s, McJ Tools was founded in Montreal,