A phosphor bronze bore brush sized for .270 / 7mm barrels. Phosphor bronze bristles are stiff enough to scrub powder fouling, copper and lead out of the bore but softer than barrel steel, so they do not damage it. Screw it onto a cleaning rod with a matching thread, wet it with a little bore solvent and run it through the barrel several times, then follow with patches or a mop to wipe the bore clean. Brushes wear with use, so it is worth keeping a spare.