Comments from the Finger: The West is getting weird. Think Swords, Sorcery, and Six-Shooters. These rules should help you include firearms in a campaign which also features regular weapons, without either group being over or underpowered.
Firearm Variant Rules
Black powder represents a paradigm shift in the art of warfare, fueling everything from powerful siege weapons to concealable, handheld guns. In many campaign settings, these firearms supplant the traditional scheme of weapons, forcing arrows, swords, and battleaxes into obsolesce. They might even be commonplace, a staple tool for hunting and home defense.
In other campaign settings, however, swords, firearms, and magic coexist equally. In these settings, since magic provides an alternative to their use, firearms are rarer and more imprecise, often requiring specialists like gunslingers to be truly effective. A setting of this type might seem very familiar, with some changes. A knight is just as likely to carry a handgun as a dagger, and infantrymen may shoulder rifles, rather than pikes, but adventurers still delve into dungeons for treasure, and castles still dot the landscape.
Damage Rolls with Firearms
Unlike other weapons, you don't add your ability modifier to the damage roll of a firearm unless otherwise stated.
Two-Weapon Fighting with Firearms
Unlike other ranged weapons, you can engage in two-weapon fighting with two light firearms. When you do so, you subtract 2 from the damage roll of the bonus attack, to a minimum of 1 damage.
Characters in most campaign worlds will not have proficiency with firearms, but in settings with widespread firearms, characters gain the following proficiencies:
|Bard||Light revolver, parlor gun|
|Fighter||Lever-action shotgun, light revolver, repeating rifle, revolver|
|Paladin||Double-barrel shotgun, revolver|
|Ranger||Hunting rifle, revolver|
|Rogue||Coach gun, light revolver, parlor gun|
|Parlor Gun||75 gp||2d4 piercing||2 lb.||Ammunition (range 30/90), concealable, light, loading|
|Revolver, Light||100 gp||2d6 piercing||3 lb.||Ammunition (range 40/120), light, reload (6 shots)|
|Revolver||100 gp||2d8 piercing||3 lb.||Ammunition (range 40/120), reload (6 shots)|
|Rifle, Hunting||175 gp||2d10 piercing||8 lb.||Ammunition (range 80/240), Reload (4 shots), two-handed|
|Rifle, Repeating||200 gp||2d8 piercing||8 lb.||Ammunition (range 80/240), Reload (12 shots), two-handed|
|Coach Gun||200 gp||3d4 piercing||6 lb.||Ammunition (range 15/45), reload (2 shots), scatter, two-handed|
|Shotgun, Double-Barrel||200 gp||2d8 piercing||7 lb.||Ammunition (range 30/90), reload (2 shots), scatter, two-handed|
|Shotgun, Lever-Action||200 gp||2d6 piercing||7 lb.||Ammunition (range 30/90), reload (8 shots), scatter, two-handed|
|Light Cannon||3000 gp||4d12 bludgeoning||225 lb.||Ammunition (range 120/360), heavy, loading, mounted, special, two-handed|
|Gatling Gun||5000 gp||2d8 piercing||80 lb.||Ammunition (range 60/180), heavy, mounted, reload (50 shots), special, two-handed|
All firearms produce a loud boom, audible out to half a mile. In addition, firearms require special ammunition and some of them have additional special properties.
Ammunition. The ammunition of a firearm is destroyed upon use. Firearms use bullets, scatter firearms use shells, and cannons use cannonballs.
Concealable. You have advantage on Dexterity (Sleight of Hand) checks made to hide this weapon.
Mounted. This weapon is normally used while attached to a tripod, wagon, or other bracing mount. While it is mounted, it can't be moved. You can mount or unmount this weapon as an action. While it is unmounted and the creature wielding it is not prone, this weapon can only be used proficiently by a Medium or larger creature with a Strength score of at least 17.
Reload. A limited number of shots can be made with a weapon that has the reload property. If you are not proficient with the firearm, you must then use your action to reload it. If you are proficient, you can choose to use your bonus action to reload instead.
Scatter. If you make an attack within this weapon’s normal range, you deal an additional die of weapon damage.
Firearms with special rules are described here.
Gatling Gun. As an action, you can rapidly fire at an area rather than a single target. Select a 15-foot cube within the weapon's range. Each creature in that area must make a DC 15 Dexterity saving throw or take damage as if hit by this weapon's attack, or half as much on a successful saving throw. This action uses 10 round of ammunition.
Light Cannon. An attack with this weapon can target a space within range, which is treated as having 10 AC. On a hit, each creature within 5 feet of the point of impact must make a DC 14 Dexterity saving throw or take half the damage rolled.
All firearms require special ammunition. Most firearms use bullets, but some require even more specialized projectiles. For example, cannons use cannonballs and all scatter firearms use shells.
Changelog: 12/14/16: Spread weapon property renamed Scatter
Reload: Proficient characters reload as an action or bonus action, whereas a creature that is not proficient must use an action
Proficiencies: Warlock gets light revolver proficiency, wizard does not
Light Cannon: Removed one attack per turn clause (covered in Loading property already)
Coach Gun: Two-handed
1/9/17: Light Cannon: Range: 120/360
Gatling Gun: 60/180
1/15/17: Mounted: Allows for firing prone
2/20/17: Light Cannon: Weight reduced to 225