Gunsmith artificers specialize in creating firearms, whether through magic or through a special mixture chemical substances similar to gunpowder. They are also able to enhance their firearms' abilities big using specialized ammunition when firing, imbuing magic in each shot. 

Note: This homebrew subclass was written using the Gunslinger Subclass Firearm Rules from Critical Role, but can be easily modified to use the firearm rules in Chapter 9 of the Dungeon Master's Guide. Consult your Dungeon Master before using this subclass (as with any homebrew).

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.

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.

Note: Due to limitations in the homebrew system, some spells have been replaced. If you own the source to the spell, you may choose to instead use that spell, replacing the bracketed one currently listed in your character's spell list.

Gunsmith Spells

Artificer Level	Spell
3rd	shield, hex(hunter's mark)
5th	heat metal, misty step
9th	slow , conjure barrage(haste)
13th	dimension door, fire shield
17th	conjure volley, destructive wave(flame strike, cone of cold)

Firearm Specialist

At 3rd level, you learn how to craft firearms, whether through magic or through a special chemical mixture that replicates gunpowder. If you craft a firearm or firearm ammunition, it takes you a quarter of the normal time, and it costs you half as much of the usual gold. The firearms described in this subclass follow the firearm rules as described in the Gunslinger Subclass from Critical Role, but your Dungeon Master may decide to use the firearm rules described in Chapter 9 of the Dungeon Master's Guide.

Additionally, you may use firearms you craft as a spellcasting focus and being within 5 feet of a hostile creature doesn’t impose disadvantage on your ranged attack rolls with firearms. 

Arcane Bullets

At 3rd level, you can briefly imbue the firearms you create and are using with traces of arcane energy. This can be described as directly imbuing the ammunition you are firing with magic, or loading a specific type of ammunition for that attack. When you hit a creature with a ranged firearm attack, you can expend one spell slot to deal force damage to the target, in addition to the weapon’s damage. The extra damage is 2d6 for a 1st-level spell slot, plus 1d6 for each spell level higher than 1st, to a maximum of 6d6. Additionally, you can apply one of the following effects.

Forceful Bullet. When you use your arcane bullet, you can change the extra damage die to d8s, and you deal an extra 1d8 force damage for every two spell levels beyond the first.

Piercing Bullet. When you use your arcane bullet, your attack become a 30 ft. long and 5 ft. wide line originating from the creature you hit. Creatures within the line must instead make a dexterity saving throw against your spell save DC. On a failed save they take the normal damage the firearm would deal, plus the additional damage from using an arcane bullet. For every spell level beyond the first, the length of the line increases by 5 ft. 

Repelling Bullet. When you use your arcane bullet, the target must succeed a strength saving throw against your spell save DC or be pushed 10 ft. away from you. Additionally, creatures within a 15 ft. cone of you must make a strength saving throw. On a failed save, they are pushed 10 ft. away from you and take force damage equal to the arcane bullet’s force damage, or half as much on a successful and they are not pushed. For every spell level beyond the first, the target is pushed an additional 5 ft, regardless of whether they saved or failed. 

Explosive Bullet. When you use your arcane bullet, you can cause the bullet to explode. Each creature within a 10ft radius of the creature you hit must make a dexterity saving throw. On a fail, they take force damage equal to the force damage taken by the creature you hit, or half as much on a successful save. For every spell level beyond the first, the radius of the explosive bullet increases by 5 ft.

Extra Attack

Starting at 5th level, you can attack twice, rather than once, whenever you take the Attack action on your turn.

Rapid Fire

At 9th level, you have learned to enhance the fire rate of firearms you craft, and are able to use them masterfully. You gain the Rapid Fire Module infusion, and it does not count towards your maximum number of infusions known. Firearms that you crafted and are wielding automatically gain this infusion, but immediately lose this infusion when it leaves your hands. Additionally, if you are using the firearm rules from Critical Role, you may repair a misfired or broken firearm as a bonus action.

Rapid Fire Module. 

Item: A ranged Weapon

You can imbue one ranged weapon that uses ammunition with this infusion. When you take the attack action with a weapon imbued with this infusion, you may use a bonus action to make an additional attack with that weapon.

Infinite Ammunition

At 15th level, you have learned how to use arcane energy to restore bullets that have been fired. You gain the Repeating Shot Infusion, and it does not count towards your maximum number of infusions known. If you already have this infusion you may replace it with another infusion that you currently are able to learn. Firearms you crafted and are wielding automatically gain this infusion, but immediately lose this infusion when it leaves your hands. Additionally, when you apply this infusion the bonus to attack and damage rolls becomes +2

Improved Arcane Bullets

At 15th level, you have learned to improve your Arcane Bullets to be more deadly. 

• You may change the damage type of your arcane shot to either Acid, Cold, Fire, Lightning, Necrotic, Radiant, Poison, or Thunder.
• Forceful Shot now changes the arcane shot damage dice from d8s to d10s, and deals additional damage dice equal to d10s.

You also gain a new Arcane Bullet.

Draining Bullet

When you use this Arcane Bullet, you heal an amount equal to half the extra damage dealt from the bullet.