Amaranthe Marksman's Rifle

This rifle is heavy and powerful, and fits much larger ammunition than it's typical counterparts. A large lever rotates to open the breech of the weapon, allowing one shot to be loaded at a time. A molded lens is attached to the top of the rifle, granting the user the ability to peer at distant targets with ease.

You gain a +1 to Attack and Damage with this weapon.

Due to the nature of the large, volatile ammunition this rifle uses, this weapon requires an attack action to reload. This cannot be ignored by feature or ability. The attack used can be part of an action to attack, or a bonus action attack.

A critical hit with this weapon ignores the target's resistance to piercing damage, and deals an additional 1d12 Piercing damage.

Specialized Weapon

When making attacks at targets within this weapon's Long Range bracket, an attack roll of 18, 19, or 20 is considered a critical hit. 

The telescopic lens on this weapon can be used as a scouting tool, much like a spyglass - Investigation and Perception checks made at a distance using this weapon can be made at advantage.

So long as you are proficient, you no longer make attacks at long range with this weapon at disadvantage.

Complicated Mechanism

When you make an attack roll with this rifle, there is a chance of a misfire. If the attack roll begins with a number 1 on the die before modifier, 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 on another attack 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: Bonus: Magic, Range, Two-Handed, Ammunition (Firearms), Reload, Slow