Since darn near as many bore brushes get used in the shop as get sold, we've packed these custom-made, top quality brushes in bulk paks to make them more convenient and less expensive. The shank is one-piece, looped and wound (not two, twisted together and chopped off). Bronze Bore Brushes - Best phosphor bronze scrubbing wire, for long life, thorough cleaning. Mfg: Brownells SPECS: Bristles: Available in bronze. Shank: Steel, looped and wound. Rifle: 3¼ (8.3cm) OAL, .17 and.20 caliber 5-40 threads, all others 8-32 thread. Pistol/Revolver: 2-1⁄8 (5.4cm) OAL, .17 caliber 5-40 thread, all others 8-32 thread. Shotgun: 2-7⁄8 (7.3cm) OAL, 5⁄16"