Fatal Bullet Feat 16
Source Pathfinder Guns & Gears
You're especially talented at striking your enemies in their most vulnerable areas. When you critically hit with a fatal firearm, you deal an additional die of the appropriate size and damage type for the fatal trait after doubling the weapon's damage. For example, after getting a critical hit with a fatal d12 weapon, you add an additional 1d12 damage to the attack after doubling its damage.
Traits
Anything that doesn't list another rarity trait (uncommon, rare, or unique) automatically has the common trait. This rarity indicates that an ability, item, or spell is available to all players who meet the prerequisites for it. A creature of this rarity is generally known and can be summoned with the appropriate summon spell.
GunslingerThis indicates abilities from the gunslinger class.