Edit: I'm not 100% sure on the Exploding rules, but I'm fairly happy with them right now. The +4 bonus to attacks against heavily-armored creatures could be a big advantage, but since bounded accuracy makes damage more important than attack bonus, this isn't as big an advantage as previous editions. The Adult Blue Dragon may have an effective 15 AC instead of 19 AC, but 1d10+Dex damage will barely scratch it. The exploding damage has the potential to be very powerful, but in playtesting so far no one has rolled a 10 even twice in a row yet, but they really love the rule because of the potential.
FWIW, here are my firearm rules:
Weapons:
Arquebus, Matchlock: Cost: 80gp; Dmg: 1d10 piercing; Weight: 12 lbs; Properties: Ammunition (range 50/200), Exploding, Loading (6), Misfire (1-3), Two-handed
Musket, Flintlock: Cost: 240gp; Dmg: 1d10 piercing; Weight: 10 lbs; Properties: Ammunition (range 70/280), Exploding, Loading (3), Misfire (1-2), Two-handed
Rifle, Flintlock: Cost: 480gp; Dmg: 1d10 piercing; Weight: 10 lbs; Properties: Ammunition (range 100/400), Exploding, Loading (3), Misfire (1-2), Two-handed
Pistol, Flintlock: Cost: 240gp; Dmg: 1d10 piercing; Weight: 2 lbs; Properties: Ammunition (range 20/80), Exploding, Loading (3), Misfire (1-2)
Pistol, Wheellock: Cost: 400gp; Dmg: 1d10 piercing; Weight: 3 lbs; Properties: Ammunition (range 20/80), Exploding, Loading (3)
Blunderbuss: Cost: 300gp; Dmg: 1d6 piercing; Weight: 10 lbs; Properties: Ammunition (range 30), Loading (3), Misfire (1-2), Scatter, Two-handed
Dragon Pistol: Cost: 250gp; Dmg: 1d6 piercing; Weight: 4 lbs; Properties: Ammunition (range 15), Loading (3), Misfire (1-2), Scatter
Ammunition and Equipment:
Powderhorn (100): Cost: 10 gp. Powder for 100 rounds Weight: 1 lb.
Shot (100): Cost: 10 gp. Bullets for 100 rounds Weight: 2 lbs.
Scattershot (50): Cost: 20 gp. 50 rounds of pellets for blunderbuss or dragon pistol. Weight: 2 lbs.
Gunpowder Cartridge: Cost: 5 sp. Weight: —
Bandolier: Cost 5 gp. Weight: 2 lb.
Buff Coat: Cost: 10gp. AC: 11+Dex; Weight: 8 lb.
Pikeman's Armor: Cost: 400gp. AC: 14+Dex (max 2); Weight: 20 lb.
Descriptions:
Arquebus: An arquebus is a shorter, heavier musket. Arquebuses require two hands to operate. An arquebus can be used as a melee weapon. This requires two hands and inflicts 1d6 points of damage.
Musket: A musket is a large handheld long gun which requires a fork rest in order to fire; not having the rest imposes disadvantage to the attack. Muskets require two hands to use. A musket can be used as a melee weapon. This requires two hands and inflicts 1d6 points of damage.
Rifle: The vast majority of firearms are smoothbore, meaning that the inside of the barrels are smooth. Rifling, the addition of spiraling grooves inside the barrel, greatly improves range and accuracy, but it is an expensive process because it must be done by hand by experienced craftsmen.
Pistol: Pistols are about the size of a man’s forearm. Two pistols or more pistols are called a brace, and were commonly worn in pairs or more because of their slow reload time. A pistol requires one hand to fire. A pistol can be used as a melee weapon, inflicting 1d4 points of damage.
Blunderbuss: This weapon fires pellets from its trumpet-shaped barrel, making it an effective fowling weapon or close-fighting personal defense weapon. Each creature in a 30-foot cone must make a DC 13 Dexterity saving throw. A creature takes 2d6 piercing damage on a failed save, or half as much damage on a successful one. Note: does not have the exploding property.
Dragon Pistol: A favored weapon of the dragoons, the dragon pistol fires pellets from its flared barrel. Each creature in a 15-foot cone must make a DC 13 Dexterity saving throw. A creature takes 2d6 piercing damage on a failed save, or half as much damage on a successful one. Note: does not have the exploding property.
Matchlock: The first common firearm, the matchlock firing mechanism is a lit match cord, secured in a clamp, which is dropped into the priming pan, igniting the powder. Matchlocks are prone to misfiring, fickle in damp or humid conditions; and they will not function in the rain. All attacks in wet or humid conditions impose disadvantage. The light and smell of the burning match imposes disadvantage on Dexterity (Stealth) checks. Matchlock pistols are not available.
Flintlock: Flintlocks are a newer invention, extremely rare and expensive. The flintlock replaces the lit match with a small piece of flint which, when the trigger is pulled, strikes a piece of steel to cause a spark that ignites the powder in the priming pan, discharging the gun.
Wheellock: Wheellocks use an internal mechanism which allows the gun to be ready to fire with no outside source of ignition, while also protecting the firing mechanism and priming pan from the elements. Reloading is no less complicated because the moving parts still need to be reset. Wheellocks are not prone to misfiring like matchlock and flintlock firearms. Each wheellock mechanism must be handcrafted by a skilled gunsmith, making the cost of equipping rank-and-file troops with this superior technology prohibitive.
Bandolier: A bandolier holds twelve gunpowder cartridges. If a character wearing gunpowder cartridges is hit by a fire attack, he must make a DC 13 Dexterity saving throw. A target takes 1 point of fire
damage for each cartridge on a failed save, or half as much damage on a successful one.
Gunpowder Cartridge: A cartridge holds one shot of powder in a pre-measured paper cartridge. Using a cartridge from a bandolier reduces the time needed to load a firearm by one round.
Buff Coat: Effectively padded leather in a yellow-tan buff color, these vests provide a minimum of protection without sacrificing mobility. Unlike normal padded armor, they do not impose disadvantage to Stealth checks.
Pikeman's Armor: Effectively a breastplate and helmet, this armor was commonly worn by infantry that needed armor to defend from pike attacks, but also needed to be mobile on a rapidly changing battlefield that employed artillery and muskets. This armor and a morion helmet was the common gear throughout Europe, but is most associated with the conquistadors.
Firearm Properties:
Ammunition: Ammunition is loaded by jamming the bullet (a round ball), black powder, and wadding to secure it all, down the barrel. A ramrod is very often included in the stock below the barrel to aid in loading.
Exploding: Exploding weapons ignore up to 4 points of armor, including shields. In effect, the creature gets its bonus to AC for Dexterity and any magical effects, but only gains a bonus for armor with higher than 14 AC, including natural armor. In addition, any time maximum damage is rolled, the player may re-roll and add to the damage. A player can continue rolling as long as the roll results in maximum damage.
Loading: Because of the time required to load this weapon, you can fire only one piece of ammunition from it when you use an action, bonus action, or reaction to fire it, regardless of the number of attacks you can normally make. Reloading requires undistracted attention, which takes a number of actions equal to the loading value. If you are damaged while reloading, you must make a Constitution saving throw, as concentration, or lose that round's progress. You cannot load a weapon while incapacitated.
Misfire: If the d20 roll for an attack equals the misfire amount or less, the attack misses regardless of any modifiers or the target’s AC. In addition, the firearm is jammed, and must be cleared out and adjusted. This takes one round in addition to the loading time.
Scatter: This type of weapon shoots a hail of pellets, attacking all creatures within a cone. Instead of the attacker making an attack roll, defenders must make Dexterity saving throws to decrease damage. Being within 5 feet of a hostile creature doesn’t impose disadvantage on your ranged attack rolls.
Additional Rules:
Fighting Style: Firearms
You gain a +2 bonus to attack rolls you make with firearms, and you can use a bonus action to reload a firearm in addition to, or in place of, your regular action.
Credits: influenced by and adapted from rules by
born2streak,
Nicholas Bergquist,
Paizo,
James Raggi
