Engineer

Hit Points Hit Dice: 1d12 per level
Hit Points at 1st Level: 12 + your Constitution modifier
Hit Points at Higher Levels: 1d12 (or 7) + your Constitution modifier per fighter level after 1st

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

Rapid Repair Upon reaching 10th level, you learn how to quickly attempt to fix a jammed gun. You can spend a grit point to attempt to repair a misfired (but not broken) firearm as a bonus action.