Info

A large, dark, bronze machine gun that resembles a shark, the barrel coming out of the mouth and fins for handles. On the sides of the body, there are vents for gills, which depending on how many Rev Points are used up, let out more and more smoke. Once Rev Points have reached their maximum, the mouth, eyes, and gills of the gun start to glow bright orange. The body of the gun is also covered in scratch marks, which are purposefully made to make the gun look "cooler" rather than as a result of extended use. The gun uses long spikes as ammo, so it's an effective slashing weapon, even from a range. The cartridge used for this ammo looks like a shark fin.

Rev-Points

For every attack action taken while using this weapon, add 1 Rev-Point. For every Rev-Point currently had, add 1d4 to it's attack rolls. Subtract 1 Rev-Point for every round you don't attack with the weapon, or don't use the Rev-Keep action. The gun can only have up to 5 Rev-Points at a time (6d4 damage), but can still be used even if that cap is reached. The gun has 15 ammo points, and for every bullet shot (d4 rolled) on your turn, you subtract 1 ammo point. Once you have no more ammo, you must reload to shoot again, which takes either 1 action, or 1 attack action.

Rev-Keep 

You can spend a bonus action to prevent your Rev-Points from going down on your turn, if you don't attack with the weapon on that turn.

 

Reload (15), Misfire (3)

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: Ranged Weapon Attack: Slashing, Damage, Combat, Reload, Misfire