Marksman

While all Fighters learn to draw a bow or hurl a javelin, those trained as Marksmen dedicate their lives to mastering ranged weapons of all types. Often, their deadly skills are backed up with an unmistakable swagger and unshakable confidence. Relying on their innate talents and signature grit, there are few challenges a true Marksman cannot overcome.

Credit to Laserllama on GMBinder for this subclass.

Elite Training

Your specialized Marksman training has given you proficiency in firearms and enhanced your reaction times. When you make a Dexterity ability check or saving throw, you can roll a d6 and add it to your roll. You can use this feature after you roll, but before you know if your roll is a success or failure. You can grant yourself this bonus a number of times equal to your Dexterity modifier (minimum of once), and you regain all expended uses when you finish a short or long rest.

In addition, whenever you use Action Surge, you have advantage on your next attack. 

Steady Aim

You can quiet your body so as to fire with deadly accuracy. If you start your turn and are not surprised or incapacitated, you can choose to Focus, which applies the features listed below until the end of your current turn:

• Your speed is reduced to 0 feet.
• Your weapon attacks score a critical hit on a roll of 19 or 20.
• You have advantage on attack rolls with ranged weapons until you hit a target with a ranged weapon attack.
• When you roll a 1 or 2 on a damage die for an attack you make with a ranged weapon, you can re-roll the die. You must use this new roll, even if the new roll is a 1 or a 2.

Cunning Shot

Your reflexes are almost supernaturally fast. You add your proficiency bonus to your Initiative rolls while conscious.

You have also learned to identify and exploit even the smallest weak points in your enemy's defenses. Your attacks with ranged weapons ignore resistance to piercing damage.

Reposition

When you use Second Wind, your walking speed increases by 10 feet, and any opportunity attacks against you are made at disadvantage until the end of your current turn.

Reliable Strike

Starting at 15th level, you learn to trade accuracy for swift strikes and you make even impossible shots with ease. Your normal and long range for your ranged weapon attacks increases by a number of feet equal to 10 times your Fighter level. In addition, if you take the Attack action on your turn and have advantage on an attack roll against one of the targets, you can forgo the advantage for that roll to make an additional weapon attack against that target, as part of the same action. You can do so no more than once per turn.

Legendary Marksman

Your marksmanship is supernatural in its precision. When you use Focus, the benefits last for 1 minute, your weapon attacks score a critical hit on a roll of 18–20, and you have advantage on all ranged weapon attacks for the duration. This effect only ends early if you move more than 10 feet in one turn, or you are incapacitated. Also, when you use your Elite Training feature, you gain a bonus to that ability check or saving throw equal to 2d6.