Quality tipton Ultra Jag 6 mm /.243 nickel-plated drawing mandrel. Solvent-resistant brass mandrel for barrel cleaning. External thread 8-32. Recommended for use with Tipton wiper bars. If you've used a classic brass Jag with no finish, you've probably come across this before.
Modern solvents dissolve brass very quickly and your brass Jag changes color literally before your eyes. Not only is your Jag noticeably damaged, but because you can still see the blue traces of corroded brass on the swab, you have no idea when the barrel of your gun is really clean. If you follow the golden rule that until the pad is clean, the barrel is not clean, the barrel is often left in contact with the solvent for too long and subsequently damaged.