A Gunsmith is a master craftsman in firearms development and trained marksman. Starting out, they hone the functions of firearms into a masterwork weapon, crafting their own Arcane Firearm and using it as a spell focus. They specialize in damage dealing more so than other artificers, and are highly effective ranged combatants. Their abilities allow them to design specialized ammo in order to target specific weaknesses in enemies and are able to attack with extreme prescision and deadly force at a distance. By using superior tactics and combining the use of spells, their weapon and magic ammunition they can create unique circumstances that can harrass and eliminate any foe.

Arcane Armory

Starting at 3rd level, the Gun Mage subclass grants a primary firearm. In addition to the weapons featured in the firearms section in the core rulebook, you will have access to those below. The primary firearm is considered a spell focus and may be enhanced with a number of infusions equal to the Artificers Proficiency bonus. If the Arcane Firearm is used in melee as an improvised weapon (or a different weapon using an infusion to enhance the weapon with a melee feature) the damage counts as magical. If destroyed or lost, a Gunsmith may produce another using 100 GP in metal and materials to bind to themselves to a new Arcane Firearm. Only one Arcane Firearm may be bound at once, and the prior bound firearm is destroyed in the process of binding a new one. An Arcane Firearm is magically linked to the Gunsmith and its position in the current plane of the Artificer is always known.

Primary:
-Double Barrel: Reload 2/1d12 Damage/120 ft. Range - Misfire 1
-Triple Barrel: Reload 3/1d12 Damage/100 ft. Range - Misfire 1
-Quad Barrel: Reload 4/1d10 Damage/80 ft. Range - Misfire 1
-5 Shot Revolver: Reload 5/1d8 Damage/100 ft. Range - Misfire 1
-6 Shot Revolver: Reload 6/ 1d6 Damage/80 ft. Range - Misfire 1
-Volley Gun: Reload 9/3d4 Damage/60 ft. Range - Misfire 2 (Note: The Volley Gun has 3 total shots and +2 to hit)

Standard ammunition may be produced using 1 GP worth of metal and reagents in rounds equal to Proficiency bonus plus Intelligence modifier and rolling a DC 15 Smithing check. A Gunsmith may produce up to Intelligence mod plus Proficiency bonus x5 standard ammunition per hour. On a failure, half the ammo (rounded up) is produced.

Arcane Ammunition

A standard projectile can be enhanced into Arcane Ammo that  is considered to deal magical damage. Converting requires and equal amount standard ammunition and a DC 15 Intelligence check to produce, and can convert up to Intelliegence modifier x10 into special ammo per long rest, or Intelligence modifier x5 ammo per short rest (a Gunsmith's minimum Intelligence modifier is considered 1 for this purpose). Failure requires double the standard ammo used to produce an equal amount of special ammo.

Converting Arcane Ammunition to a different type may be done in an hour of work with no cost using a DC 15 Intelligence check to convert up to Intelligence modifier x10 into a different type of Arcane Ammo.

At 8th level, you may produce ammo with both a single elemental damage type and one physical damage type.

At 13th level, you may create 'Slayer Rounds' and add a specific creature type (Abberation, Beast, Celestial, etc.) that loses it's Natural Armor bonus to AC against the Arcane ammunition you produce.

Ammo Types:
Elemental - Acid, Cold, Fire, Force, Lightning, Necrotic, Poison, Radiant, and Thunder.
Physical - Bludgeoning, Piercing, Slashing

Arcane Firepower

At 9th level Proficiency modifier is added to the damage of spells cast by the Gunsmith using their Arcane Firearm. In addition, Proficiency bonus for makin standard attacks with firearms is doubled.

Rapid Fire

The Gunsmith becomes adept at attacking multiple enemies at range, and at 15th level they may use a full action to attack an amount of enemies with their Arcane Firearm equal to their Proficiency bonus. In addition, they may make a standard attack with their Arcane Firearm using a bonus action.

Arcane Gunsmith Spells

3rd - Chaos Bolt
3rd - Magic Missile

5th - Spiritual Weapon
5th - Heat Metal

9th - Elemental Weapon
9th - Lightning Bolt

13th - Stone Skin
13th - Stone Shape

17th - Conjure Volley
17th - Swift Quiver

Tool Proficiency

When you adopt this specialization at 3rd level, you gain proficiency with smith's tools. If you already have this proficiency, you gain proficiency with one other type of artisan's tools of your choice.