This gun A.C.E is a projectile weapon that changes its form to its owners needs or desires.
This gun can use up any projectiles as its ammunition to use up.
Role 4d8 for damage. If you role a natural 20, A.C.E automatically shoots an exact duplicate of the ammunition you used.
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.
This weapon has the following mastery property. To use this property, you must have a feature that lets you use it.
Sap. If you hit a creature with this weapon, that creature has Disadvantage on its next attack roll before the start of your next turn.
Notes: Range, Ammunition (Firearms), Reload, Sap