Oh, hi, welcome back to programming. Do I have enough in the queue to maintain regular posting again for a while? Let’s find out together.

This is a short, untested idea for a conversion I was looking at from Scion to a modernized D&D 5e (I eventually went with Savage Worlds, instead, which will get some explanation in the next few weeks).

Basics of Saving-Throw-Based Firearms

Proficiency in different firearms is handled the same way as other weapon types. However, instead of making an attack roll when using a firearm, the target of the attack makes a Dexterity saving throw as if avoiding a spell. The difficulty of the saving throw is equal to 8 + [Attacker’s Dexterity Modifier] + [Attacker’s Proficiency Bonus (if proficient)]. In most cases, a successful save avoids all damage. At the weapon’s long range increment, the target gets Advantage on the save.

Cover works normally to add to saving throws (as it would against spells that require a Dexterity save). Shooting into a melee, with cover granted by the shooter’s allies, if the target successfully saves, the GM may require allies on the line of attack to save as well or take the damage.

Firearms do not add the attacker’s ability score bonus, and cannot critically hit. Modern firearms do a base of 3d4 damage for a small-caliber handgun, and increase by a die size for additional caliber and weapon size (up to two steps for each). A high-caliber modern rifle does 3d12 damage. Special effects (such as a spread) may also exchange damage for the effect.

Modern firearms damages are a little bit better than bow damage (see design notes), so keep how useful you want firearms to be in a medieval/Renaissance-level game in mind when adjusting the damage ranges.

Armor that is specifically bulletproof may add Resistance to damage from firearms.

Firearms Actions

Aiming: Use your action to aim at a target that you can see that is within your firearm’s range. If the target does not leave your range, does not leave your line of sight for more than a round, and you do not move more than five feet per round or aim at a different target, you can maintain your aim upon the target. You can use subsequent rounds’ actions to improve your aim up to three total times. Each instance of Aiming adds one more die of weapon damage (to a maximum of +3 dice of damage for aiming for three rounds; e.g., a weapon that does 3d8 does 6d8 after three rounds of aiming).

Burst: Use three times as much ammunition for the attack with a weapon that can fire automatically to add one die to the damage total.

Full Auto: Empty the clip for the attack with a weapon that can fire automatically to double the weapon’s damage total and impose disadvantage on the target’s save.

Spray: You target a cone up to the weapon’s range. All targets within the cone must save against the attack’s difficulty. Successful saves take half damage (rather than no damage), unless the target has an evasion-style ability.

Spread: Treat firearms with spread (like a shotgun) as a narrow cone or line attack. For each target hit, targets further away that are also hit take a die less damage (i.e., the pellets don’t keep going after hitting a target).

Suppression: With a gun that can fire multiple times per round (i.e., not a single shot with long reload period), spend three times as much ammunition as would normally be required for an attack in order to ready an attack against enemy targets that become available in a general direction of attack. When a target becomes available while the attack is readied, that target has Disadvantage on the save. Targets know that they will provoke an attack and will have Disadvantage (because there are bullets flying wildly in their direction).

Example Firearms

  • Small Pistol (3d4)
  • Police Pistol (3d6)
  • Heavy Pistol (3d8)
  • Slug Shotgun (3d10)
  • Shot Shotgun (3d8 , Spread)
  • Light Rifle (3d8)
  • Hunting Rifle (3d10)
  • Sniper Rifle (3d12)
  • Machine Pistol (3d4, Auto abilities)
  • Submachine Gun (3d6, Auto abilities)
  • Machine Gun (3d8, Auto abilities)
  • Heavy Machine Gun (3d10, Auto abilities)
  • Belt-Fed Stationary Machine Gun (3d12, Auto abilities)

Design Notes

This whole idea mostly comes down to the lack of a touch AC in 5e. Rather than invent an armor-piercing feature for an attack-roll-based gun that requires calculation of how much of a target’s AC is from armor, this essentially targets Dex-only. That it makes spray-based attacks use exactly the same mechanic (instead of an attack roll for single targets but a save for multiple) is a bonus.

Damage is deliberately high for the weapons because of the lack of ability bonus to damage and capacity to critically hit. Most longbow users are doing something on the order of 8-10 damage per hit, on overall average, depending on how high their ability add is (and before considering magic, feats, or other damage-increasing abilities). So a gun that did 2d8 would be more or less similar under this system (thus kicking it up a bit for modern firearms to be clearly better than bows).