Sniper for roux

While many rogues use poison and knives, some have latched on to a newer technology: the gun. A snipers job is to pick off the most dangerous targets on a battlefield while keeping back form the frontline. While not a silent assassin, staying so far away form the action keeps snipers hidden and lethal. 

One shot one kill

Starting when you pick this archetype at third level shooting and killing an enemy on your turn automatically reloads yore weapon as the same action

Tinkerers thief

Starting when you pick this archetype at third level you can use thieves tools to repair your gun after misfiring instead of tinkers tools. 

Silent hunter

starting when you pick this archetype at third level you are able to cast hunters mark once per long rest at first level

Hidden shot

At 9th level, you have become expert at staying hidden even after firing. If you were hidden before attacking, any enemy that is 60 feet or further from you has disadvantage on any Perception checks made to spot you until the beginning of your next turn.

Piercing shot

Starting at 13th level when you make a firearm attack against a creature, you can attempt to fire through multiple opponents. The initial attack gains a +1 to the firearm’s misfire score. On a hit, the creature suffers normal damage and you make an attack roll with disadvantage against every creature in a line directly behind the target within your first range increment. Only the initial attack can misfire. Only the initial attack can sneak attack. You can only use this once per long rest.

Boom headshot

Starting at 17th level when you attack a creature that has at least one head with yore gun and roll a 20 on a sneak attack roll, you shoot throgh one of the creature's heads. The creature dies if it can't survive without the lost head. A creature is immune to this effect if it is immune to piercing  damage, doesn't have or need a head, has legendary actions, or the GM decides that the creature is too big for its head to be pirced by a bullet. Such a creature instead takes maximum sneak attack damage. You can only use this feature once per short or long rest.