Gunsmith

You have discovered how to utilize sparkpowder to create weapons of mass destruction.

Sparkpowder Specialist

Through study and practice you have learned to craft Firearms and Ammunition. 

You gain proficiency with Firearms. See the Rules for Firearms addendum.

During a Long Rest you may craft a Sparkpowder Pistol. This Pistol can be used as a Spellcasting Focus. The Sparkpowder Pistol uses your Intelligence Modifier for Attack and Damage Bonuses.

During a Long Rest you must do maintenance on your Firearms. The number of Cartridges you can fire out of your pistol before it needs maintenance is 6. Firing it more may result in catastrophic failure.

BlunderBussin'

You can now fire two Cartridges per Attack Action. 

You've learned the Bonus Action Reload.

You've infused the Arcane into the smelting process for your Gun Metal, hardening the Barrels. You can now fire up to 12 Cartridges per Long Rest.

During a Long Rest you can craft a Blunderbuss. This Firearm uses your Intelligence Modifier for Attack and Damage Rolls. This Firearm holds 2 Cartridges and may be fired from your off-hand for a Bonus Action. This deals 1d8 Force Damage to all creatures within a 10 Foot Square. Creatures within 5 Feet must make a Strength Saving Throw or be Knocked Back 5 Feet landing Prone. 

Rifling

You can now fire 3 Cartridges per Attack Action.

If you roll a 20 on a Firearm Damage Roll the target of the roll is Blinded Permanently. 

Your metallurgic skills have increased, allowing you to create rifled barrels. During a Long Rest you can craft a Smokepowder Rifle. The Smokepowder Rifle can be used as a spellcasting focus. The Smokepowder Rifle can be fired 4 times before needing maintenance.

Your Smoke Powder Pistol can now be fired as a Bonus Action and can be fired 18 times before needing maintenance.

BOOM! Headshot

You can now fire up to 4 Cartridges per Attack Action.

If you roll a 20 on a Firearm Damage Roll against a target that has less than 75 health the target dies.