Black Powder Sorcery

This subclass is based on the Black Powder Sorcerer subclass created by Kobold Press. Some minor changes have been added to increase the viability of the subclass, as well as improve quality of life and make its feature layout more intuitive.

Your innate magic comes from the explosive power of raw alchemy and black powder. You parents may have been alchemists, whose long exposure to alchemical reagents mingled with a latent talent for magic in their bloodlines and caused you to be born with such abilities. Or you may have been experimented upon—with or without your permission—when you were younger and those alchemical experiments brought this unexpected magical power to the surface. Whatever the catalyst for your powers, they bring with them an affinity for black powder, allowing you magical prowess that exploits its power to your benefit.

Gun Mage

You gain proficiency with firearms and your choice of alchemist’s supplies or tinker's tools. Additionally, you learn the mage hand cantrip if you don't already know it, which has the following special features for you:

• You can cast the mage hand cantrip as a bonus action and may conjure an additional hand with the same casting. This mage hand must stay within 5 ft of you and can only be used to hold a firearm with the light property. You can conjure additional hands in this way when you reach higher levels in this class; you gain a third hand when you reach 5th level, then an additional hand at 11th and 17th levels.
• When you cast mage hand or as a bonus action on a later turn, you may draw, drop, reload, or stow one firearm for every mage hand you have conjured.
• When you use the Attack action, you can choose to make any of the attacks granted by the action using a firearm held in one of your mage hands. When attacking with a firearm in one of your mage hands, you can choose to use your Charisma modifier for the attack and damage rolls. 
• When a creature within a range equal to 5 ft times your proficiency bonus targets you with an attack or harmful spell, you can use your reaction to fire a firearm held by one of your mage hands at the attacker. Being within 5 ft of the target does not impose disadvantage on this attack.

Alchemist's Supplies

You are proficient in alchemist's supplies.

Tinker's Tools

You are proficient in tinker's tools.

Fusillade

As an action, you may activate Fusillade to simultaneously make an attack with every firearm that you are currently holding in a mage hand. You can use this feature a number of times equal to your proficiency bonus, and you regain all expended uses of it after you take a long rest.

At 2nd level, you can expend sorcery points as part of this action to magically reload any unloaded firearms in your mage hands, spending 1 sorcery point per firearm that you reload in this way. Any ammunition created in this way disappears after the attack.

Boom Goes the Dynamite

You can use the destructive power of black powder to its fullest extent. When you roll the highest number on any damage die for an attack using a firearm or any other black powder weapon, that damage die will explode. When a die explodes, you may roll an additional die of the same type and add the result to the total damage. If you roll the highest possible number on an additional die rolled in this way, it can explode as well.

The maximum amount of dice that may explode on a single attack is equal to your proficiency bonus.

Volatile Ammo

Beginning at 6th level, you can attack twice, instead of once, whenever you take the Attack action on your turn as long as at least one of those attacks is with a firearm you are holding in a mage hand. Any attacks you make with a firearm are also considered magical for the sake of overcoming immunity and resistances.

In addition, you can expend 1 sorcery point as a bonus action to further empower the gunpowder within your firearms. Until the beginning of your next turn, any attack you make with a firearm deals an extra 1d6 of the weapon's damage type or fire damage on a hit. At 14th level, you can expend 2 sorcery points in this way to increase the extra damage to 2d6.

Explosive Restoration

At 14th level, you can replenish your sorcerous power by absorbing the latent energy of black powder. In a ritual that takes 1 minute, you can absorb the power of up to 30 cartridges worth of black powder (equivalent to a full gunpowder horn).

For every 6 cartridges worth of gunpowder, you regain 1 expended sorcery point, up to a maximum of 5. The black powder is consumed in the process. Once you use this feature, you can’t use it again until you finish a long rest.

Ensuing Shot

At 18th level, when you use the [Tooltip Not Found] action using a spell slot of 4th level or lower, you can make one attack with a firearm as a bonus action. This firearm can be held by you or by one of your mage hands. Alternatively to a single attack, you may activate your Fusillade ability as a bonus action if it is available to use.