I don't know, but I've purchased thousands of rounds of Winchester ammunition packaged in white boxes from Wal-Mart, including the 100 round Value Packs, and never had a misfire. This, in numerous semi-auto pistols, revolvers and carbines. I'd sure like to jump on board about the terrible WWB or USA9MMVP or whatever ammo, but I've just never had a problem with it. Good plinking ammo within my humble experience.....ymmv