Montana X-Treme Bronze Bristle Brush for Shotguns (5/16 x 27 Thread) 20/28 ga SPECIFICATIONS BRAND: MONTANA X-TREME CA PROP 65: YES CLEANING CALIBERS & GAUGES: .20, .28 CAL CLEANING ITEM TYPE: BRUSHES MATERIAL: BRONZE USAGE: SHOTGUN DESCRIPTION Montana X-Treme Bronze Bristle Shotgun Cleaning Brushes will tackle the toughest cleaning operations - including plastic wad residue - with ease. Bristles are heavy duty bronze on a brass core for confidence against accidental marring of the bore. 5/16 x 27 thread.