Your interest in the arcane has led you to the invention of the Gun of the Arcana.

Spellcasting

When you reach 3rd level, your inventive mind allows you to wield the Gun of the Arcana

Recipe Book. You have a recipe book containing five 1st-level wizard Spells of your choice that do not have a range of touch, or self, as well as not requiring concentration. Your book is the repository of the wizard Spells you know. You may spend 1 hour and 50 gold to copy down any wizard spells you find into your book, but only if they are 4th level and below, and follow the same rules as above.

Spell Charges. The biggest difference between traditional casting and the gun is the invention of Spell Charges. On a long rest, you may spend an amount of Tinkering Points equal to the spell's level and any material components that a spell consumes to fill a charge with a spell. If the spell requires a component with a gold value, but does not consume it, it must be present during the creation process.

The shells act similarly to scrolls in that once used, they cannot be used again. The shells also lose their magical properties at the start of every long rest.

Spellcasting Ability. Intelligence is your Spellcasting ability for your wizard Spells, since your cunning mind and ability to create has led you to this invention. You use your Intelligence whenever a spell refers to your Spellcasting ability. In addition, you use your Intelligence modifier when Setting the saving throw DC for a wizard spell you cast and when Making an Attack roll with one.