You're particularly adept at firing at armored opponents and hitting the teeny-tiny bits of them that aren't armored. If you have Eagle Eye, you can ignore any armor your target may have.
This schtick never works with any kind of area attack.
EagleEye defeats armor, but it takes some effort to defeat high-technological DragonArmor. For every shot you have spent aiming, you may ignore armor of up to four points. Armor that you can't ignore works normally - you either ignore the armor completely, or it has full normal effect.