An Uzi SMG

The Uzi is a small, compact, submachine gun.  It fires extremely fast, but is incredibly inaccurate.  Many criminals favor this weapon as a sidearm that can be drawn quickly for close-range combat. 

Weapon Stats.  Light, Reload (30 shots), Burst Fire, Range 30/120 ft., Ammunition (Bullets).  

Damage.  (2d4) piercing damage.  

Burst Fire.  You can expend 15 pieces of ammunition to spray the uzi in a 20 ft. cube originating from a point within range.  Any creatures within the cube must make a Dexterity Saving Throw (DC 15), taking (3d4) piercing damage on a failed save, or half as much damage on a successful save. 

Special.  You can attack twice with the uzi, as long as you have the ammunition to do so.      

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: Damage: Piercing, Damage: Piercing, Damage, Combat, Range, Ammunition (Firearms), Reload