Ace, +3

This magic +3 revolver is a testament to Halfling ingenuity. This weapon can be stored in an extra dimensional pocket(that is unaffected by the detriments of a Bag of Holding) as a bonus action. This space appears as a tattoo of the weapon on one of your limbs or around your waist. You can draw this weapon from its pocket either as a bonus action, or as part of the action used to attack. 

This weapon has 5 charges. You can use a Bonus Action to expend 1 charge to give yourself advantage on the attack. You can expend 3 charges to deal an extra 5 damage. Alternatively, you can expend 5 charges for Both. The weapon regains all charges at the end of a long rest.

Variant Rule: The DM may allow this weapon to grow in power with the character as they level. The DM decides when the weapon evolves and what causes it to evolve. It could be a set amount of time, a specific number of enemies, or a display of heroism/power. If this rule is implemented, this item gains the Attunement Required feature; however, it does not count against your normal number of attunements. Instead if ANYONE other than the main user successfully fires the weapon, even once, all advancements are immediately lost and the weapon must be evolved again. The evolution path may be the same or different as decided by the DM.

It’s up to you to decide whether a character has proficiency with a firearm. Characters in most D&D worlds wouldn’t have such proficiency. During their downtime, characters can use the training rules in the Player’s Handbook to acquire proficiency, assuming that they have enough ammunition to keep the weapons working while mastering their use.

Notes: Bonus: Magic, Range, Ammunition (Firearms), Reload, Vex