I bought a bunch of the 20 grain super x stuff and it was gabage. Every 3rd or 4th case would split and need to be picked out with my pocket knife. It would shoot 3" plus at 100 yards for 3 shot groups. In there defense, I sent some ruptured cases back to winchester and they send me a gift certificate for all the ammo i had purchased. They offered to pay to have my gun shipped away to a gunsmith, fixed if necessary, and shipped back.
The winchester supreme 17 grain stuff, however, I never had a problem with. Kept em under a half inch at 100 yards and no fail to fire/eject/ruptures or anything.
Depends what you've got. It might be junk, it might not.