My Current Firearm Rules

Since I’m designing my own Modern-Day OSR system, I’ve been taking a crack at a number of rules and concepts. One that is quite hard to get right, in my opinion, is firearms.

Firearms in OSR systems have always seemed very lackluster to me. This ranges from D&D’s renaissance firearms to modern-era games where the weapons aren’t much deadlier than a thrown knife.

They tend to be either way too detailed or not detailed enough. In that context, I wrote these rules based on the statistics of average types of gunfights. Most gunfights happen at 6 feet or less, with an advantage to the defender but also a first-shot advantage to whoever attacks first.

Generally, I did not concern myself with pedantic details regarding firearms or their differences, nor with types of scenarios that would almost never come up, such as sniper duels or vehicle-mounted machine guns. Likewise, damage is determined with the consideration that humans in my system, and in most OSR systems, have an average of 1d6 HP, which is not very much.

The system I’ve devised is roughly based on Invisible College and Gang Busters B/X and would be a fine drop-in replacement for either of those games.

Firearm System⌗

Damage⌗

Ballistic Damage: Unlike other damage types, Ballistic Damage has an explosive quality. When rolling damage, if the maximum value on the die is rolled, you reroll and add the damage of both rolls together. If you roll another maximum, repeat.

Damage Die Types: Damage dice are typically organized by caliber.

1. Varmint Rounds: Such as .22 LR, do 1d4 damage.
2. Small Caliber: Often found in handguns, such as 9mm or .45 ACP, do 1d6 damage.
3. Intermediate Cartridge: Such as the 5.56 NATO or 7.62x39, do 1d8 damage.
4. 12 Gauge 00 Buckshot: Does 2d4 damage.
5. Full-Power Cartridge: Such as the 7.62x51 NATO or .30-06 Springfield, do 1d10 damage.
6. Anti-Materiel Cartridge: Calibers of this class include .50 BMG or 12.7×108mm Russian, and do 2d10 damage.

Rate of Fire⌗

Weapons have variable rates of fire depending on their reloading and firing mechanisms. These rules represent how many accurately aimed shots a character can squeeze off in a roughly 6-second combat round.

1. Semi-automatic: Weapons always get two shots per round, whether handguns or rifles.
2. Pump-action, Lever-action, single-action: These forms of non-semiautomatic designs always get 1 shot per round.
3. Double or Multi-Barreled: Weapons sporting more than a single barrel can fire all barrels at a single target in a single round or split fire between two targets.
4. Burst-Fire Modifier: Weapons with burst fire do not modify the number of times a character can shoot. Instead, they modify semi-automatic fire, adding +1 to attack and increasing the exploding damage range by 1 at the expense of 3/5 ammunition per attack. So a handgun with a burst option would do exploding damage on a 5-6 instead of just 6. Weapons with a special burst mode typically spend only 3 ammunition, while automatic weapons in burst fire mode spend 5.
5. Fully-Automatic Modifier: Weapons that are fully automatic, like burst weapons, modify semi-automatic fire, adding +2 to attack and increasing the exploding damage range by 2 at the expense of 10 ammunition per attack. Fully automatic weapons can also perform suppressive fire for 20 ammunition; this creates a cone in front of you. Anyone caught in the cone must make a saving throw or be hit.

Ammunition & Reloading⌗

Ammunition is how many times a weapon can be shot before reloading and is listed next to a weapon’s stats. Certain modes of fire use more than 1 ammunition per round, so keep that in mind. Most ammunition is typically reloaded in single discrete magazines, but that varies from weapon to weapon.

Reloading: Reloading always takes 1 action, and you cannot attack and reload on the same turn with the same weapon. For tube-fed weapons such as shotguns, lever-action weapons, or revolvers without a speed loader, a player can load three shells or bullets per turn into the tube. For belt-fed or older style flintlock or gunpowder weapons, reloads can take from 2-3 turns.

Range & Distances⌗

Weapons have effective ranges that modify their attack bonuses, listed for normal and far distances. Normal range applies no penalties, while far range applies a -2 to attack. Anything beyond far range applies a -4 to attack and -2 to damage.

Firing in Melee: Firing your weapon while someone is in melee combat with you applies a -2 to attack.

Firing Into Melee: Firing at two or more people in melee or grappling applies a -2. Failing the attack means you hit an unintended target if the attack roll was above their AC.

Firearm Maneuvers⌗

Aimed Shots: Taking a turn to aim and not move adds a +2 to the next round’s attack, up to a maximum of +4. Adding optics can improve this to a maximum of +6.

Concealed Draw: Actively readying your draw and firing stance before a fight breaks out gives a +1 to initiative, and for the first round of combat +1 to attack.

Akimbo Guns when wielding two handguns or SMGs at the same time you get to attack at their full fire rate for both weapons that turn, the weapon in your primary hand is -2 to attack, and the weapon in your off is -4, or when burst/automatic firing that is -4 and -6 to attack.

Fan the Hammer: when using a revolver with a hammer a character may fan the hammer, each shot after the first is a cumulative -1 to attack.

Handguns⌗

Submachine Guns⌗

Rifles⌗

Shotguns⌗

Revolvers⌗

Lever-Action Rifles⌗