Uncanny Accuracy( Epic Level Handbook, p. 68)
You can ignore anything less than total cover or total concealment when using ranged weapons.
Point Blank Shot (PH) , Precise Shot (PH) , Spot 20 ranks, DEX 21,
When throwing or shooting a ranged weapon, you can ignore any cover bonus to the target's AC (up to a maximum of nine-tenths cover) or any miss chance conferred by the target's concealment (up to a maximum of nine-tenths concealment). If the target has total concealment or total cover, the AC bonus or miss chance applies normally.