Gunslinger

Your skill with firearms means you are able to fire off volleys with both hands. This feat grants you the "Off-Hand Gunslinger" bonus action ability.

On your turn when you take the attack action, if you are wielding a firearm in your off-hand you can use your bonus action to make a number of attacks equal to half your normal number of attacks per action (min 0). These attacks act in the same way as those granted by the "two weapon fighting" bonus action except for the following changes:

1. "light Melee" is replaced by "Ranged" as the attack type.
2. Your firearm must be magazine fed, a revolver, or double barreled to make more that one additional attack.
3. In the case of double barreled your max number of possible attacks is 2. 
4. your firearm must not have the "Heavy" or "Two-Handed" property. 

You must be proficient in firearms to use this feat.