Wizards attempt to create multiple ways to infuse their magic but none have tried harder than the Artificer. A Wizard with a dream and a will strong enough can wield a gun making it a staple of their character. The ones who mainly study the evocation school of magic are the ones who are usually more interested with this type of gun slinging.

Firearm Meddling

 You gain Proficiency in firearms and gunsmith tools

 

Arcane Chamber

You can use a firearm as an arcane focus. It still functions as a regular firearm would, and can fire mundane ammunition. Such a firearm is bound to you, through a 1-hour ritual (similar to the Eldritch Knight's Weapon Bond). 

You may bind only one firearm this way. These weapons are considered magical for the purposes of overcoming resistance and immunity. You can summon this weapon as a bonus action on your turn.

Your bonded firearm can cast cantrips at multiple targets instead of a singular target. The damage of the cantrips per shot don’t scale with level but instead deal the first level damage plus your intelligence modifier. The cantrip must be a ranged spell attack to fire in this way.

            For example, if you're a 5th level wizard, firebolt does 2d10 fire damage. When firing with your bonded firearm you could choose 2 different targets, or the same target, and split the damage die against each, still using your spell attack bonus for each roll. On a hit the target would take 1d10 + intelligence modifier fire damage on a hit.

Charged Chamber Shot

As an action you can release the Magic stored in the weapon as a ranged spell attack dealing 2d10 + 1d10 per spell level expended (to a max of 5d10) + intelligence modifier damage of the chosen damage typing. The range on this attack is 200 feet.

You can use this a number of times equal to your intelligence modifier. Must finish a long rest to replenish your uses of this feature.

Firearm Caster

You can cast spells through your firearm making them faster and condensed. A spell with a range other than touch, and requires a dex save (example: fireball) can be condensed into a spell attack that targets only one creature dealing the same damage of the original casting of the spell. The spell cannot exceed a level equal to your intelligence modifier + 1.

Spells that can target multiple creatures (such as scorching ray and magic missile) from the evocation school can add your intelligence modifier to the damage rolls from the shots that come from your bonded Firearm.

You may also bond up to two firearms using the Arcane Chamber feature.

Outlawed Firepower

Your bonded weapon can ignore damage resistances but not damage immunities. In addition the Charged Chamber feature increases to a max of 7d10 and the distance is increased by another 100 feet.