Firearm Rules Modifications

Introduction

White Leviathan is a long campaign, and it features numerous situations where firearms will come into play. Because mid-nineteenth century firearms aren’t extensively profiled in the standard Call of Cthulhu rulebook, this section offers the Keeper a wealth of information to make the campaign as authentic—and lethal!—as desired. This page offers modifications of the existing Call of Cthulhu firearms rules and establishes a simplified damage system. This is followed by “Notes on Period Firearms,” which offers a brief history of nineteenth-century firearms. The final section is the “White Leviathan Armory,” a detailed listing of the most common firearms found in the campaign.

Firearm Rules Modifications

The following guidelines offer campaign-specific clarifications and modifications of the standard Call of Cthulhu firearms rules.

Firearms Skill
The Firearms skill is treated as per the standard rules, but only two specializations are available: “Pistols” and “Rifle/Shotgun.” The former covers all single-handed firearms, including pistols, pepperbox guns, and the Colt Paterson revolver. The latter covers all longarms, including muskets, rifles, blunderbusses, and shotguns. The base skill levels are the same as the standard rules: 20% for Pistols and 25% for Rifle/Shotgun.

Switching Guns
Because personal firearms are fairly expensive in the 1840s, a character is likely to own a single gun they’ve carried faithfully for many years. For this reason, an NPC’s “Combat” stats may include something like, “.54 Pistol” or “M1777 Musket” instead of “Pistol” or “Rifle/Shotgun.” However, skill in any particular firearm extends to all types in its category, so a character owning a .54 Sea Service flintlock pistol would have the same proficiency with a .69 Harpers Ferry cap-and-ball pistol.

Having said that, the Firearms skill doesn’t grant immediate understanding of an unfamiliar mechanism. Someone only accustomed to flintlocks may be puzzled by a caplock rifle, and revolvers are new for everybody. While it’s easy to understand a new mechanism if it’s demonstrated, figuring it out on one’s own takes some ingenuity—especially in the middle of a firefight! To successfully operate a new type of firearm, a character must pass three different rolls: Firearms, Idea, and Mechanical Repair. Only one roll is permitted each round.

Firearm Damage
The Call of Cthulhu rules feature dozens of firearms with all manner of damage scores. This makes sense for the twentieth century—there’s wider variety of cartridges, calibers, loads, bullet types, action types, and barrel lengths. Modern pistols are also considerably more accurate than their nineteenth-century counterparts! For the purposes of White Leviathan, the keeper is encouraged to use a simplified system based solely on weapon type and caliber:

These damage values are generally lower than the standard rules. For instance, the official rulebook gives the damage of a .58 Springfield musket as 1D10+4, while the above table offers a simplified 1D10. There are two reasons for this:

Simplicity
While mass-produced guns existed in the 1840s, there were more hand-crafted weapons in circulation than today, and more fluctuations in caliber—for instance, muskets with a .71 bore were generally fitted with .69 caliber balls, or even smaller calibers as the barrel continued to foul. The above system makes assigning damage simple: What’s the caliber of the shot? Is the gun a pistol or a longarm? There’s your damage! Of course, the Keeper is free to use modifiers, maybe a +1 for an exceptionally-crafted weapon. Also note that muskets and rifles have longer ranges than pistols, which increases the chance of getting an Extreme success and earning additional “impale” damage.

Wider Range of Damage
Using the standard rules, the minimum damage a character takes from being shot with a .58 Springfield is 5 hit points, with the average damage being 9 hit points. This becomes lethal very quickly! By eliminating damage modifiers—the “+4” in this case—the system allows for more randomness when determining damage. In other words, more chance of a “graze.” Of course, an Extreme success with a firearm still inflicts “impale” damage, so even a 1D10 musket can inflict 1D10+10 points of damage, especially within its base range!

Range
For the sake of simplicity, the following firearms use similar “Base Range” statistics to those given in the official Call of Cthulhu rulebook. Keepers interested in more accurate ranges are invited to visit the author’s “Deadlands 1876 Armory.”

Quick Reloading
During particularly frenzied moments, a muzzle-loader can be loaded more quickly by spitting the ball into the barrel without using wadding, firmly tapping the butt onto the ground to seat the ball, and firing as usual. The lack of wadding decreases accuracy by imposing a –1D10 penalty die to the Firearms roll, but skipping the ramrod reduces the loading time by one full round.

Fouling the Barrel
For obvious reasons, black powder weapons must be cleaned regularly, as residue in the barrel quickly degrades the accuracy of the firearm. This is usually done by swabbing the barrel with hot water; but if no water is available, a soldier can always urinate down his barrel instead! As the barrel becomes increasingly more fouled, it takes an additional round to load the firearm, and a –1D10 penalty die is applied to the Firearm roll.

Bullet Molds
Until the invention of the Minié ball and the advent of metallic cartridges, many shooters made their own ammunition. This requires five things: a supply of lead, a heat source, an iron skillet, a casting ladle, and a bullet mold. As lead has a melting point of 623°F, the embers of a campfire are usually sufficient. It requires a successful Art/Craft (Blacksmith), Firearms, or Mechanical Repair roll to cast a dozen bullets. A failed roll results in a burn worth 1D4 damage.

White Leviathan > Auxiliary Materials > Firearms
[Rule Modifications | Notes on Period Firearms | White Leviathan Armory]
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Author: A. Buell Ruch
Last Modified: 13 August 2023
Email: quail (at) shipwrecklibrary (dot) com
White Leviathan PDF: [TBD]