Base Class: Rogue
The aim of your training has been to deliver death from a distance. But snipers are as diverse as they are dangerous.They are Tinkers' who create new inventions, guardians of nature who defend ancient woods, and scouts who stalk the far edges of a battlefield Snipers are more than just their tools: patience, preparation, and strategy are key to every successful operation.
Level 3: BONUS PROPICIENCIES
When you choose this Archetype at 3rd level you gain proficiency with tinker's tools, heavy crossbow, and firearms. You also learn how to use tinkers tools to produce gunpowder and ammunition and repair firearms. Additionally, you may learn how to modify and upgrade firearms as you gain levels in this class
Level 3: CAREFUL AIM
Starting at 3rd level your ranged weapon attacks with crossbows and firearms no longer suffer disadvantage due to long range. You gain an additional way to use your Sneak Attack; you don't need advantage on the attack roll to use your sneak Attack against a creature if you move 0 feet during your turn, no enemies are within 5 feet of you, and you don't have disadvantage on the attack roll. All the other rules for Sneak Attack still apply to you.
LOW PROFILE
Starting at 9th level your ranged weapon attacks with crossbows and firearms do not suffer disadvantage while you are prone. You also have ½ cover against all ranged attacks while you are prone and standing only costs you 5 feet of movement.
SNIPER’S NEST
At 13th level when you make a Ranged Weapon Attack while hidden you make a Dexterity (Stealth) check contested by your opponent's Wisdom (Perception) if you win the contest your position is not revealed. If you spend 10 minutes you can set up a defensive firing position. While in this position you have l Cover against Ranged attacks, if you are Prone then this bonus increases to 1/4 cover.
OVERWATCH
Starting at 17th level while you are at a higher elevation than your enemy your attacks have advantage and you can use your reaction to make a ranged weapon attack against an enemy that moves within 5 feet of an ally.