Gunsmith

In their arcane workshop the gnome finally finishes the arcane inscription on their masterpiece. They pick up their creation, turn around and aim it at the target at the end of the workshop. After a flash of light and loud boom the target is in pieces.

Gunsmiths create firearms with some extra arcane flare, and they know how to use them. 

Arcane Gunsmith

Upon choosing this archetype at 3rd level, you gain proficiency with firearms. You may use tinker’s tools to craft ammunition at half the cost, repair damaged firearms, or even draft and create new ones (DM’s discretion). Some extremely experimental and intricate firearms are only available through crafting.

Your ammunition counts as magical for the purpose of overcoming resistance and immunity to nonmagical attacks and damage.

You can use a firearm as an arcane focus for your artificer spells.

You can use either the Gunslinger subclass firearm rules from Critical Role or the firearm rules from Chapter 9 of the Dungeon Master’s Guide.

Gunsmith Spells

Starting at 3rd level, you always have certain spells prepared after you reach particular levels in this class, as shown in the Gunsmith Spells table. These spells count as artificer spells for you, but they don’t count against the number of artificer spells you prepare.

Gunsmith Spells

ARTIFICER LEVEL	SPELL
3rd	guiding bolt, hellish rebuke
5th	acid arrow, scorching ray
9th	fireball, lightning bolt
13th	ice storm, wall of fire
17th	cone of cold, flame strike

Extra Attack

Beginning at 5th level, you can attack twice, instead of once, whenever you take the Attack action on your turn.

Firearm Casting

At 9th level, you can cast a spell into a firearm. The spell is stored in the firearm until you use the attack action to cast the spell, until you cast another spell into the firearm, or until the end of the next short or long rest.

When you take the attack action with that firearm you can cast the spell except the spell’s range is the range of the firearm.

Empowered Shots

At 15th level, you can increase your firearm’s firepower with your arcane power. Once per turn, when you take the attack action you can expend a spell slot into your firearm. You can roll one additional weapon damage die equal to the spell slot expended.