Handgun Training (Pathfinder Feat)
From D&D Wiki
Handgun Training [Combat]
With enough training, anyone can strike their target in a vital spot.
Prerequisite: Exotic Weapon Proficiency (firearms), Improved Critical, Dex 20, Int 20
Benefit: Increase your critical threat range with a one handed firearm by 1. Add +2 to critical confirmation rolls.
Special: May be taken up to 5 times.