"Don't play your hand unless you're sure you have that ace in the hole."

To Attain the Ace of Spades:

First, you must have the (Golden) Gunslinger subclass. Second, during a short rest, you must design a draft by succeeding on a tinkering (Intelligence) check with a DC of 13. Third, collect 500 GP for the necessary materials and visit a smith to forge the frame. Finally, complete the gun by crafting it. This can be done by succeeding on 5 tinkering checks with a DC of 16 (each check can be done once per long rest). The goal of each check is to manufacture a new piece of the gun, so failing does not impede previously succeeded checks.

A gun that stacks the odds in your favor. Now you can gamble with not just cards, but fate itself. This unique gun serves as a testament to your capabilities. It holds 8 rounds and has a misfire modifier of 3 due to its experimental nature. It has a range of 50/100 ft. and can be heard in a 350 ft. radius. When firing at long range, this weapon deals half damage. It also has the exotic perks Firefly and Memento Mori.

Firefly. After killing an enemy with a precision shot, the enemy explodes dealing 1d6 fire damage to enemies in a 5 ft. radius that fail a Dexterity saving throw (DC equal to 8 + your proficiency bonus + your Dexterity modifier).

Memento Mori. When equipped, you gain 1 perception. Additionally, reloading immediately after a kill changes the next 3 rounds to deal 1d12 piercing damage.

Firearms are a new and volatile technology, and as such bring their own unique set of weapon properties. Some properties are followed by a number, and this number signifies an element of that property (outlined below). These properties replace the optional ones presented in the Dungeon Master’s Guide. Firearms are ranged weapons.

Reload. The weapon can be fired a number of times equal to its Reload score before you must spend 1 attack or 1 action to reload. You must have one free hand to reload a firearm.

Misfire. Whenever you make an attack roll with a firearm, and the dice roll is equal to or lower than the weapon’s Misfire score, the weapon misfires. The attack misses, and the weapon cannot be used again until you spend an action to try and repair it. To repair your firearm, you must make a successful Tinker’s Tools check (DC equal to 8 + misfire score). If your check fails, the weapon is broken and must be mended out of combat at a quarter of the cost of the firearm. Creatures who use a firearm without being proficient increase the weapon’s misfire score by 1.

Ammunition
All firearms require ammunition to make an attack, and due to their rare nature, ammunition may be near impossible to find or purchase. However, if materials are gathered, you can craft ammunition yourself using your Tinker’s Tools at half the cost. Each firearm uses its own unique ammunition and is generally sold or crafted in batches listed below next to the price.

THIS IS UNOFFICIAL MATERIAL

These game mechanics are usable in your campaign if your DM allows them but not refined by final game design and editing. They aren’t officially part of the Dungeons & Dragons game and aren’t permitted in D&D Adventurers League events unless otherwise stated.

Notes: Damage: Fire, Bonus: Perception, Natural Weapon: Piercing, Reload, Misfire