Crack Aim (RoF Feat)
From D&D Wiki
 Crack Shot [Heroic]
Training and practice have given you an excellent aim in both melee and ranged combat, especially against Dragons.
Only available if your first class level is from a Hero class; limit one Heroic feat per character.
When attacking any creatures, you treat their size category as one larger than it actually is for purposes of their size modifier to AC. In addition, you gain a +2 on attack rolls against Dragons.