One-Hand Marksman (3.5e Feat)

Danger Zone: Once per turn as a free action you can choose one 10x10 square plus one per 6 points of base attack bonus within your first range increment. You threaten all squares contained in these danger zone, allowing you to take attacks of opportunity. Your opponents are automatically aware of any danger zone you declare.

Piercing Shot: You ignore 1 point of natural armor or armor to AC per attacks granted by base attack bonus granted to you. Additionally your attacks pierce damage reduction pretty well, ignoring a single point of DR per point of base attack bonus and the damage dealt may not be reduced below your base attack bonus or the damage dealt (whichever is lower), regardless of the size of the damage reduction, immunity or abilities that lower damage dealt.

Shot Through The Heart: As a standard action you make a single attack with a -4 penalty, if it hit it is multiply damage by 3 and the struck creature suffer immediate bleedout (as if he took a number of bleed points equal to his constitution score. Creatures without circular system or heart are immune to this tactical maneuver.

Tag Shot: When you make a successful ranged attack you gain a +1 bonus to hit and a +2 bonus to damage rolls against the creature you struck, this bonus is cumulative. It automatically reset whenever you attack a different creature or miss an attack.