I've used a few brands of brass in 6.5x55 mm and the only ones that had undersized flash holes were Igman, aka Hotshot, cases. I decapped them with an undersized decapping pin and drilled the flash holes to standard size and they've been good since drilling them. I have yet to encounter undersize flash holes in nny/ppu brass; in my limited experience in 6.5x55 it's excellent brass. Before you toss them just check them with a small flashlight - better than guessing.
