Cobolt Precision( Magic of Incarnum, p. 37)
You can focus your soul energy into your ranged attacks, dealing more damage with successful critical hits.
Point Blank Shot (PH) , CON 13,
Once per day, you can invest essentia into this feat. You gain an insight bonus equal to the invested essentia on ranged attack rolls made to confi rm a critical threat. You gain an insight bonus equal to the invested essentia on ranged damage rolls made as part of a critical hit. (This extra damage is added before damage is multiplied for the critical hit.) Both of these bonuses apply only against targets within 30 feet. Once the amount of essentia invested is chosen, it cannot be altered and remains invested for 24 hours. You gain 1 point of essentia.