One of the things I wanted to do was follow up on a couple of optional details pertaining to my prior firearms rules, mainly regarding a few extra topics. These are not required to use the firearms rules, but they could add more granularity to the concept.

Generally, I’m not in the simulationist camp of Tabletop DMs; however, as a firearms enthusiast, I’d like to add these options all the same.

General Mechanical Overview⌗

A few mechanics I need to get out of the way to make everything listed below make a bit more sense:

1. Ballistic Damage: This is a special damage type reserved for firearms and explosives. When the maximum number is rolled on the damage die, the player may reroll the damage and add it. If they roll the maximum number again, they repeat, ad infinitum.

   This mechanic is modified by the firing mode of the weapon. A burst fire weapon expands the range in which the damage die can “explode.” For example, if a 9mm handgun rolls a max of 6 on a 1d6 die, then a burst fire PDW does exploding damage on a 5 and 6 on the 1d6. For fully automatic spray, that expands to 4, 5, and 6.

2. System Shock: In my game system, when a player takes half or more of their maximum Health Points in a single attack, they must make a saving throw to avoid going into System Shock. When in System Shock, they are stunned for 1d4 turns and do not add their Dex to their Armor Class.

3. Armor Class and Damage Resistance: Armor Class functions the same as in D&D and most standard OSR systems—a combination of the ability to avoid getting hit and the protection your armor offers. Damage Resistance, however, is a number by which incoming damage is reduced. So, for example, a Kevlar Vest might be +2 AC followed by DR 2, which negates 2 points of incoming ballistic damage.

4. Weight Slots: My system handles encumbrance by dividing it into weight slots. A standard handgun is 1 weight slot, 3 pistol mags are 1 weight slot, and a rifle is 2-3 weight slots. The number of weight slots is equal to a character’s STR score + CON score.

Overview of Caliber Categories and Subcategories⌗

Here is a repost of the general caliber groups. I don’t want to get into the nitty-gritty of each caliber’s ballistics and range, as much of that will come down to table rulings. This broad categorization works for general use:

1. Varmint Rounds (1d4 damage)⌗

• .22 LR
• .17 HMR

2. Small Caliber (1d6 damage)⌗

• 9mm Parabellum
• .380 ACP
• .38 Special
• .357 Magnum (+1 damage)
• .45 ACP (+1 damage)
• FN 5.7 (-1 damage, AP 2)

3. Intermediate Cartridge (1d8 damage)⌗

• 5.56x45mm NATO
• .223 Remington (-1 damage)
• 7.62x39mm (+1 damage)
• .300 Blackout

4. 12 Gauge (2d4 damage)⌗

• 00 Buckshot
• Slugs (1d8+1 damage)
• Birdshot (2d3 damage)

5. Full-Power Cartridge (1d10 damage)⌗

• 7.62x51mm NATO
• .308 Winchester
• .30-06 Springfield (+1 damage)

6. Anti-Materiel Cartridge (2d10 damage)⌗

• .50 BMG
• 12.7×108mm Russian

Special Ammunition Types⌗

1. Full Metal Jacket (FMJ): Standard ammunition, no modifiers.

2. Hollow Point (HP):

   • +1 damage against unarmored targets.
   • -1 damage against armored targets (damage resistance).
   • Increased chance of incapacitation (on System Shock save, target has a penalty of -1).

3. Armor Piercing (AP):

   • -1 damage against unarmored targets.
   • Ignores 2-4 points of armor.
   • “Green Tip” for 5.56mm (AP 2).
   • “Black Tip” for larger calibers (AP 4).

4. Subsonic:

   • -1 damage against targets at far range.
   • Reduced noise profile (+1 on ambush check).

5. +P (Overpressure):

   • +1 damage.
   • +1 to hit at long range.

6. Frangible:

   • -1 damage against armored targets
   • Reduced risk of over-penetration (ideal for close quarters or aircraft use).
   • +1 damage against unarmored targets at close range.

7. Tracer:

   • No damage modification.
   • +1 to hit for subsequent shots thereafter (does not stack with aiming or optics).
   • Reveals the shooter’s position (disadvantage on stealth checks).

8. Incendiary:

   • Normal damage.
   • 1-2 out of 6 chance to ignite flammable materials.
   • Dragon’s Breath Shotgun Shells (1d4 ballistic damage, 1d4 added fire damage, 1-4 out of 6 chance to ignite flammable materials).

9. Silver Tipped:

   • Normal damage.
   • Capable of harming certain supernaturals normally immune to mundane damage.
   • Extra expensive.

Barrel Length Effects on Calibers⌗

These optional rules simplify how barrel length affects ballistics by a great deal so please any gun nerds, forgive me. Barrels often apply a range bonus that only applies to far range or beyond, counteracting penalties.

Varmint Rounds (1d4 base damage)⌗

Small Caliber (1d6 base damage)⌗

Intermediate Cartridge (1d8 base damage)⌗

Full-Power Cartridge (1d10 base damage)⌗

Anti-Materiel Cartridge (2d10 base damage)⌗

Optics⌗

Optics are simple to apply, with effectiveness split between their Attack Bonus and Aim Bonus. The Aim Bonus only applies if you take the Aim Action with the optic in question. The Aim Bonus does not stack with multiple uses of the Aim action.