Pseudorealistic Selective-Fire Gunplay for ICRPG: Two Approaches

inspiration
mechanics
guns
alternative-rules

#21

MECHANIC REVISION: SCATTER

After regularly implementing the “damage cascade” revision for full-auto firearms in my game, a minor concern that arose for me after further playtesting these homebrew rules for pseudorealistic gunplay regarding shotguns and other firearms shooting multiple projectiles from a single round, i.e., those using ammunition like 00 buckshot shells with the “scatter” tag.

Shotguns had become a bit overpowered counting each pellet that hit (based on an additional D8 roll after a the initial successful D20 DEX check) as an independent strike doing GUN effort, averaging a hyperlethal 20-point blast when fired. While this definitely captured the feel of the devastating power of buckshot at close range, it set shotgun wounds very low on the survivability curve compared to those from a three-shot or five-shot burst from a submachine gun or assault rifle, which average 11 and 13 points respectively, where each hit represents an actual bullet, frequently of greater mass than a buckshot pellet and sometimes also traveling at higher velocity. (Example, a 9x19mm “+P” SMG round is nearly three times the mass of a single 00 pellet of “low-recoil” police buckshot, and both travel approximately the same speed when fired from archetypal weapons that use them.)

This in-game power discrepancy between shotguns and automatic weapons was made even more concrete by the convergent effects of the probability distributions associated with the mechanics in use. Average damage for scatterguns was focused and centered very reliably around 20 points of damage, owing to the bell curve yielded by multiple D8 rolls, while the full-auto burst was governed by a single, substantially more “swing-y” D8 damage roll a used for all of the individual strikes in a burst before the damage cascade decrement was applied, tying all of the bullets together in their aggregated damage output, sometimes very high and sometimes very low.

I tweaked the rule for shotguns using “scatter” ammo like buckshot, so that instead of each independent strike from a typical 9-pellet load dealing GUN effort, now only the first one does, similar to the damage cascade implemented for full-auto guns. Every additional shotgun pellet of the remaining eight that hits on a subsequent D8 roll adds a single point of extra damage, parallel and equivalent to the 1-point minimum for all full-auto strikes.

Effectively, shotguns firing buckshot now deal DOUBLE GUN effort, averaging 9 points of damage per blast instead of 20–still enough to kill a one-heart target almost half of the time with a single shot, but ranking them just behind SMGs and assault rifles firing full-auto or multishot bursts, which feels more realistic and provides for more expedient, more dramatic, and more satisfying ballistic combat in the game when the bullets (and pellets) start flying…

(Theoretical maximum damage also has a more realistic cap. A lucky max damage burst of five shots from an SMG (only a small fraction of one percent likely) can do 30 points of damage before any GUN bonus. Conversely, a max damage shotgun blast (significantly more likely with an approximate 1.5% chance) deals 16 points before any bonus—down from a vanishingly small chance of the former theoretical maximum of 64!)

Shotguns under this amended rule for damage output remain highly lethal, very effective for characters, and smooth to run at the table.


#22

Interesting discussion on the modelling of gunplay with ICRPG. One thing I’m missing though is what is the goal of these rules?

By this I mean, what kind of play/story are these rules supposed to support? Which stories actually involve realistic usage of guns? A battlefield? Hunting? Drug cartels? Police action? It seems to me that with realistic simulation of guns they are so lethal that they would be mostly used for intimidation rather than actual use for any significant fraction of play time, so really gun rules used for RPGs are usually not very realistic, but I’m curious about your intent and thoughts.


#23

All of the above. :sunglasses:

In truth, this current set of homebrew firearms rules Supports and facilitates every one of the hypothetical scenarios you listed.

I use them mostly for cosmic horror games and post-apocalyptic scenarios, but I also use them for a variety of modern one-shots and WWII-era commando-style adventures.

The goal is to keep firearms practical to play at the table but more believable in terms of (some of) their in-game effects, as an alternative to treating individual (types of guns) like magical spells, with proprietary rules, gonzo effects, and unrealistic modes of application that shatter player (and GM) immersion in grittier, more grounded adventure scenarios.

I am specifically selective in simulating aspects of gunplay. I want the most likely outcome from getting hit by a shotgun blast or a burst from an SMG to be death for a typical human, but I balance that lethality by counting bullets in favor of endless supplies of ammunition, and governing hit probabilities (largely) in line with the way things work in the real world. In practice, this adds some very interesting dimensions to the game, offering some drama and meaning to player choices round by round.

There is a time, a place, and a setting for “I see the six bad guys, and I mow them all down with my shotgun.”

These gun rules are for all the other times.


#24

Or, optionally… :sunglasses: (I miss the TSR era… :grinning:)

https://youtu.be/XeWWcO4p6qg&t=544


#25

Not bad if you have about ten hours for a single gunfight. :laughing: