This strange weapon began as a wicked-looking dagger of unknown origin, but as soon as you laid your hands upon it, the weapon transformed. As if reading your mind, it reformed into the shape of a strange, three-barreled hand cannon. It does not require ammo, but once all three shots have been fired, it takes until the start of your next turn for the weapon to cool down and recharge its shots for another volley. You may fire the gun one barrel at a time, or discharge all three barrels simultaneously.

-When you fire one barrel, you are able to make more precise shots. It has a +2 to attack and damage rolls, and deals 2d8 Piercing damage on a successful hit.
-When you fire all three barrels, you go for a heavy blow. It deals 3d10 piercing damage on a hit.

Whether you fire all three at once, or fire three consecutive shots, firing all barrels in a single turn means you must roll 1d20. On a natural 1, the weapon fires successfully, but is rendered inoperable for the remainder of combat.
If you strike a killing blow, you will begin to hear the whispers of those you've killed each time you fire this weapon at a humanoid. After five kills with it, you must roll on the insanity chart, to determine your mental stability.

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, Damage, Combat, Range, Ammunition (Firearms), Reload, Sap