Gunsmith

Gunsmiths are masters of engineering, artificers known for their inventing and wielding of firearms, and for forging brand-new and never seen weapons powered by a combination of science and magic. They aren’t as generally destructive as their Bombardiers cousins, specially to the environment they are in, but when their crosshairs lock onto a foe, little time will pass before a storm of lead, gunpowder and magic reduces them to nothing but ashes.

Note: I know Artillerist already fills in a bit of this subclass' fantasy, but that's kind of my problem with it. Artillerist is a halfway point between a gun artificer and a demolitionist artificer, and as someone who prefers specialization on subclasses, I thought a purely gun artificer would be a nice addition.

Firearm Tinkering

When you adopt this specialization at 3rd level, you learn to use your Tinker’s Tools to craft ammunition at half the cost, repair damaged firearms, and maybe even draft and create new ones (DM’s discretion). You may utilize both or either Critical Role or Dungeon Master’s Guide firearms (DM’s discretion).

Additionally, when you are wielding a magical firearm, you may use your Intelligence modifier, instead of Dexterity, for attack and damage rolls (modify in the character sheet).

Gunsmith Spells

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	Gunsmith Spells
3rd	Guiding Bolt, Magic Missile
5th	Magic Weapon, Scorching Ray
9th	Flame Arrows(can be used on bullets), Haste
13th	Blight, Elemental Bane
17th	Hold Monster, Immolation

Arcane Modifications

Also at 3rd level, you learn how to magically modify your firearms, which enhance their physical capabilities in a variety of ways. Whenever you finish a short or long rest, you may put a new arcane modification on a firearm you touch, or you may replace one already active arcane modification with a different one. You can have up to 3 arcane modifications active at the same time, divided amongst any number of firearms. This number increases to 4 at 6th level, to 5 at 8th level, to 6 at 11th level, to 7 at 14th level, to 8 at 17th level, and to 9 at 20th level.

Additionally, as a bonus action on your turn, you may rapidly adapt to the situation at hand, changing an active arcane modification for a different one. You can do so once, regaining the ability to do so again when you finish a long rest, or by expending a spell slot.

Arcane Loader

If you load no ammunition in the firearm, it produces its own, automatically creating one piece of magic ammunition when you make a ranged attack with it. The ammunition created by the weapon vanishes the instant after it hits or misses a target.

Arcane Round

(Prerequisite - 6th level)

As a bonus action on your turn, you may load an arcane round into the chosen firearm, expending a spell slot of 1st-level or higher to fire a magical bullet. On your next attack with it that hits, the weapon deals damage as normal, except it's force damage, and then it additional damage equal to a number of d10s equal to 1 + the slot's level.

Armor Breaking Round

(Prerequisite - 6th level)

As a bonus action on your turn, you may load a piercing round into this firearm. Your next attack that hits deals an additional 1d4 damage, and, on a hit, it deals cold damage instead of its normal type, and on a hit, the target’s AC is reduced by 2 until the beginning of its next turn. You can use this modification once, regaining the ability to use it again when you finish a short or long rest, unless you expend a spell slot to use it again.

Bayonet Mount

A mount affixed to the end of the firearm, which allows a dagger to be placed in it. While a dagger is in the bayonet mount, you can make a melee weapon attack with the dagger while wielding the firearm. In addition, when you take the Dash action while a dagger is in the bayonet mount, if you move in only a straight line during the Dash, you can make a melee weapon attack with advantage with the dagger while wielding the firearm.

Close Combat Adjustments

Being within 5 feet of a hostile creature doesn't impose disadvantage on your ranged weapon attack rolls. In addition, when you would be able to make an opportunity attack against a creature, you can make a ranged weapon attack using this firearm as your reaction instead.

Elemental Receiver

When you apply this modification to a firearm, choose one of the following damage types; acid, cold, fire, or lightning. Whenever you make an attack roll, you may choose for the firearm to deal that damage type instead, and if you are dealt damage of that type, on your next turn, an attack that hits with the firearm deals an additional 1d6 damage of that type.

Force Charge Chamber

(Prerequisite - 11th level)

As a bonus action, you can begin to charge up arcane energy within a special charging chamber in the firearm. On your next turn, you can then use an Attack to fire a single concentrated bullet at a target within 60 feet of you that you can see. Make a ranged attack roll against the target, dealing force damage equal to a number of d6s equal to twice your proficiency bonus on a hit. After taking the Attack action this way, you must wait 1 minute for the chamber to cool before you can charge up another charge chamber. If you do not fire on the turn after you charge it up, the energy is wasted and you take 2d6 fire damage, although you may charge it up again afterwards.

Freezing Round

(Prerequisite - 6th level)

As a bonus action on your turn, you may load a thundering round into this firearm. Your next attack that hits deals an additional 1d4 damage, it deals cold damage instead of its normal type, and on a hit, the target’s speed is reduced by 15 feet until the end of its next turn. You can use this modification once, regaining the ability to use it again when you finish a short or long rest, unless you expend a spell slot to use it again.

Hooking Round

(Prerequisite - 6th level)

As a bonus action on your turn, you may load a hooking round into this firearm. Instead of making an attack against a creature, on your next attack, you instead fire a hook at a creature within range to try and disarm it. The creature must succeed on a Strength saving throw against your spell save DC; it is disarmed on a failed save. The object falls five feet away from the creature in your direction. Alternatively, you can also target a small object with the hookshot and pull it to you, making an attack roll against it instead. 

You can use this modification once, regaining the ability to use it again when you finish a short or long rest, unless you expend a spell slot to use it again.

Light Frame

The firearm gains the light property, and it weighs half of its normal weight.

Lightning Round

(Prerequisite - 6th level)

As a bonus action on your turn, you may load a lightning round into this firearm. Your next attack that deals lightning damage instead of its normal type, and on a hit, as long as the target took damage, they must succeed on a Constitution saving throw against your spell save DC. On a failed save, it becomes stunned until the end of your next turn. You can use this modification once, regaining the ability to use it again when you finish a short or long rest, unless you expend a spell slot to use it again.

Precision Scope

You can use your bonus action to aim the firearm. The next ranged weapon attack you make with the firearm on this turn ignores half cover and three-quarters cover, it is made at disadvantage if the target is within 30 feet of you, and on a hit it deals an additional 1d8 damage to the target. You can only use this bonus action if you haven't moved during this turn, and after you use the bonus action, your speed is 0 until the end of the current turn.

Quickfire Mechanism

After making a ranged weapon attack using this firearm, you can use your bonus action to make an immediate ranged weapon attack with disadvantage.

Radiant Charge Chamber

(Prerequisite - 11th level)

As a bonus action, you can begin to charge up arcane energy within a special charging chamber in the firearm. On your next turn, you can then use your action to fire an intense beam of concentrated energy at a solid surface within 60 feet of you that you can see, tracing an amount of terrain equal to a 30 foot long 5 feet wide line, though you can choose how you aim it and if it bends or turns. Creatures within the area must succeed on a Dexterity saving throw against your spell save DC or take an amount of radiant damage equal to a number of d8s equal to twice your proficiency bonus on a hit. After firing the beam this way, you must wait 1 minute for the chamber to cool before you can charge up another charge chamber. If you do not fire on the turn after you charge it up, the energy is wasted and you take 2d6 fire damage, although you may charge it up again afterwards.

Range Scope

You do not get disadvantage for attacking at long range with the chosen firearm. In addition, you can use your bonus action to aim the firearm, giving you advantage on the next ranged weapon attack roll made with this weapon on the current turn, unless the target is within 30 feet of you. You can only use this bonus action if you haven't moved during this turn, and after you use the bonus action, your speed is 0 until the end of the current turn.

Rotary Charge Chamber

(Prerequisite - 11th level)

As a bonus action, you may transmute your firearm into having a greater number of rotating smaller barrels. The next time you take the Attack action, damage you deal becomes halved, but the number of attacks you can take with this firearm is doubled. After taking the Attack action this way, you must wait 1 minute for the chamber to cool before you can charge up another charge chamber. If you do not fire on the turn after you charge it up, the energy is wasted and you take 2d6 fire damage, although you may charge it up again afterwards.

Sound Suppressor

While you are hidden from a creature, ranged weapon attack rolls with the chosen firearm are made with advantage. Additionally, when you are hidden from a creature and miss it with a ranged weapon attack using this weapon, making the attack doesn't reveal your position, and attack rolls with this firearm don’t make any sound.

Spring Holster

You can stow or draw the chosen firearm freely without using an action or object interaction.

Thundering Round

(Prerequisite - 6th level)

As a bonus action on your turn, you may load a thundering round into this firearm. Your next attack that hits deals an additional 1d10 damage, it deals thunder damage instead of its normal type, and on a hit, the target becomes deafened until the end of your next turn. You can use this modification once, regaining the ability to use it again when you finish a short or long rest, unless you expend a spell slot to use it again.

Tracking Round

(Prerequisite - 6th level)

As a bonus action on your turn, you may load a tracking round into this firearm. Your next attack that hits using this weapon marks the target. For the next 2 hours, as long as the creature is within 1000 feet of you, you can maintain concentration to see the contour of its silhouette through any object or material, as if there was nothing between you and the creature. You can use this modification once, regaining the ability to use it again when you finish a short or long rest, unless you expend a spell slot to use it again.

Extra Attack

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

Gunsmith's Arsenal

Starting at 9th level, you gain the following benefits:

• Quickdraw. You can stow a firearm then draw another firearm as a single object interaction on your turn.
• Trademark. You have learnt to comercialize your firearms, if so you wish. You may spend an hour, which can be done as part of a short or long rest, to place a magical mark on a firearm you can touch. The firearm gains the benefit of up to one of your firearm modifications that don’t have a prerequisite. However, the firearm can’t be wielded by you, or an ally, and it can’t be fired against you or an ally. The mark lasts on the firearm until you die or if you wish to dismiss it.

Arcane Frenzy

When you reach 15th level, you learn to temporarily augment yourself and your creations to better wield the weapons you wield. At the beginning of your turn, you choose to do so, as you send a burst of powerful magic through your body and the weapons you are wielding.

Until the end of your turn, whenever you deal damage with a firearm, you deal an additional 1d10 force damage, and if you were to expend a use of your arcane modifications or a firearm with an arcane modification would need to cool before charging again, the use is not expended or the firearm does not need to cool.

You can use this feature once, gaining the ability to do so again when you finish a long rest, or by expending a spell slot of 5th level to use it again.