The Sniper

You have mastered the art of stealthy killing your enemies with firearms. You know how to increase your range with said firearms. 

Mark your Target

You can cast hunters mark once per short rest. 

Can't Hide From Me

You ignore 3/4 cover when using a firearm.

Aim for the head

Your sneak attack damage are maximized when using firearms.

Gunsmith

You may craft the firearms from Mathew Mercer's Gunslinger Fighter subclass. You are also now proficient in firearms. 

Snipe

You may know add Sneak Attack to your fire arm damage. The same rules regarding when Sneak Attack is used  still applied.