Amaranthine Repeating Rifle

 This rifle has a complicated clockwork mechanism built into it, allowing it to store multiple wax cartridges and self-load them. A wielder proficient in firearms ignores the loading property with this weapon. The mechanism allows the weapon to use a single barrel and breech - resulting in more powerful shots, and better range, at the cost of reduced reliability.

Complicated Mechanism

 When you make an attack roll with this rifle, there is a chance of a misfire. If the attack roll is a 5 or below before any modifiers, the rifle malfunctions, and fails to fire. When this occurs, roll a D20. On a 16 or higher, the rifle has jammed, and will require repairing as an action or bonus action.

Budding Technology

Firearms are proving powerful and useful tools in Amaranthe. They have their drawbacks, but the penetrating power of powder weapons cannot be ignored. In the Amaranthe setting, firearms will defeat protection granted by mundane armors. A creatures AC against a firearm is reduced, unless their armor is magical or Adamantine. 

A creature's armor class versus a firearm is determined via 10 + Dexterity Modifier + Natural Armor + Magical bonuses. Certain classes gain armor benefits from other ability scores, and these do apply.

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: Range, Two-Handed, Ammunition (Firearms), Reload, Slow