Thursday, October 1, 2020

Modern Fiddly Firearms

 In my second-ever blog post, I said "i also wrote a gigantic table of firearm damage by specific real-world caliber, which is fun if your gaming group has gun nerds in it. maybe i'll post that later"

This is a refined, somewhat simplified (yes) version of that, hopefully suitable for use in games that are not mine and are run by people who have a (very slightly) lower tolerance for ~firearm verisimilitude~. It's all the sort of complicated that you figure out when you pick up a gun, not every time you fire it, so it runs fairly smoothly in play if you're not swapping stuff around all the time... Still rather complicated, though.

Damage has been reduced a little from my original system (which was designed for d20 E6 with d8 HD) to be more appropriate for GLOG, but is still very lethal. Try not to get shot.

Happy GLOGtober!


This whole thing works better if you have armor give HP instead of AC. This lets you have dramatic moments where you get knocked on your ass when someone shoots you in the chest with a rifle, only to pull off your shattered plate carrier and return fire. You can still get AC from cover, and stats if your system allows for that. My recommendation:
  1. Light armor: A flak jacket, an undercover vest, other soft body armor, etc. Doesn't get in the way. 5-10 HP. An unarmored vehicle counts as having this level of protection.
  2. Medium armor. A plate carrier with ballistic panels rated for intermediate cartridges. Quite heavy, encumbers like chain in your favorite medieval/early-modern RPG. 15 HP.
  3. Heavy armor. Hard body armor with NIJ Level IV protection, likely covering the shoulders, sides, and upper legs. Heavy and restrictive, encumbers like plate in a medieval/early-modern RPG. 20 HP.
There's also vehicle armor:
  1. Light Vehicle armor. On an APC, combat helicopter, or equivalent. You can't wear this, unless it's on an exoskeleton or something.
  2. Heavy Vehicle armor. Actual tank plating. You can't wear this, ever.
Personal armor is damaged before your HP, except by critical hits, weapons that say they penetrate its level of protection or better, and stuff that would ignore armor logically (falling damage, etc).

Vehicle armor is the vehicle's entire HP, and can only be damaged by weapons that say they penetrate its level of protection or better, or critical hits.

More advanced, rarer materials might provide higher HP values or protect at higher levels. Improvised ones might provide less HP or encumber at higher levels.


The most important part of the firearm isn't actually the firearm, it's, uh, what it fires. This is what damage is based on. Cartridge stats have three values: Damage, Recoil, and Armor Penetration. I'll explain recoil when we talk about firearms themselves.

Also noise, I guess. Something with the "quiet" tag will be hard to notice from far away or pinpoint the direction of, especially if suppressed. Something with the "loud" or "very loud" tag probably can't be suppressed effectively. 

Here's a list of some cold-war-era-to-modern stuff:

Light Pistol
Light Pistol (.22 LR, .25, .32 or .380 ACP) - 1d6 - R0 - quiet
Standard Pistol (9mm, .38 or .44 Special, .45 ACP, .40S&W) - 1d8 - R1 - quiet

Heavy Pistol
AP Pistol (HK 4.6mm, FN 5.7mm, 5.8mm DAP92, 7.62 Tokarev, sci-fi pistol) - 1d8 - R2 - AP Light
Magnum Pistol (.357 or .44 Magnum, 10mm Auto, .50AE) - 2d6 - R3 - AP Light - loud
Fuckoff Pistol (.454 Casull, sci-fi bullshit) - 3d6 - R5 - AP Medium - very loud

Intermediate Rifle
Subsonic Rifle (9x39mm, .300 AAC) - 1d10 - R2 - quiet
Intermediate Rifle (5.56 NATO/.223 Rem., 5.45 and 7.62x39mm, 5.8x42mm) - 2d6 - R2 - AP Light
High Power Intermediate (6.5mm Creedmoor, .50 Beowulf, sci-fi intermediate) - 2d8 - R3 - AP Light

Full-Power Rifle
Full-Power Rifle (7.62 NATO/.308 Win., .303 British, 7.62x54R, .30-06) - 3d6 - R4 - AP Medium - loud
Magnum Rifle (7mm Rem Mag, .338 Lap Mag, .300 Norma Mag, sci-fi rifle) - 3d8 - R5 - AP Heavy - loud
Anti-Materiel Rifle (.408 CheyTac, .50 BMG, 12.7x108mm) - 4d8 - R7 - AP Light Vehicle - very loud
Light Autocannon (14.5x114mm, 20mm, sci-fi AMR) - 6d8 - R8 - AP Light Vehicle - very loud

Light Shotgun (20 gauge) - 1d8 - R2
Standard Shotgun (12 gauge) - 3d8 - R4 - loud


The important parts of a firearm are its Size, Ammo, Sights, Action/Fire Modes, and Recoil.

Size is pretty obvious. Can you fire it effectively with one hand or not. How many slots does it take up in your inventory. That sort of thing.

Ammo is how many rounds it can hold. Reloading takes a move action (i.e. can be done in place of your movement or your action for the turn) per round, clip, or magazine loaded. If you're a Fighter maybe you can move and reload at the same time.

Sights determine your effective range. You get -2 to hit for every increment beyond your range you're attacking at.
  • A gun with no sights has a 10' range.
  • Iron sights on a pistol or a bead sight on a shotgun have 30' range.
  • Iron sights on a rifle or most reflex sights have 60' range. Reflex sights give an extra +1 to-hit.
  • Magnified optics have a range of 100' per magnification multiplier. Probably there is some penalty for trying to use a high minimum magnification under a given range.

Actions determine what fire modes are available with a firearm and if it can be used for iterative attacks:
  • Single-shot firearms have to be reloaded between each attack. Break-action shotguns and rifles are probably the most common form of this, but there are some single-shot bolt-action rifles as well.
  • Manual (pump, lever, bolt, single, etc)-action firearms have to be manually cycled between each attack. It's assumed that you're doing this automatically as long as you have a free hand, but it means you can only make one attack with them per round even if you have multiple attacks.
  • Semi-automatic firearms fire one shot with each pull of the trigger. You can use them to make as many attacks as you have in a round. If you're a Fighter, maybe you can also double tap to fire a 2-round burst with one.
  • Fully automatic firearms fire continually while the trigger is held. You can probably only fire bursts and full-auto with them. If you're a Fighter, maybe you can also use them to fire single shots.
  • Select-fire firearms can be used as if they were either semi- or fully automatic.

Fire Modes modify recoil, damage, and potentially area of effect:
  • Single shots cost 1 ammo and don't modify recoil or damage at all.
  • Burst fire costs 3 ammo, doubles recoil, and adds 1 die of damage. A double-barreled firearm counts as firing a burst if you fire both barrels.
  • Full-auto fire costs 5 ammo, trebles recoil, and either adds 2 dice of damage or hits everyone in a cone (roll the attack roll once, compare to all ACs or have them roll Dex vs your attack or whatever).

Recoil starts with the recoil value of the cartridge, then is lowered by the following:
  • Ignore recoil if fired from a fixed mount on a vehicle or fortification or whatever.
  • -4 recoil if set up on a bipod or fired from a prone position, etc.
  • -2 recoil if the barrel is real long and/or heavy, like on a machine gun or full-length sniper or hunting rifle.
  • -2 recoil if it has a stock and you're using it.
  • -1 recoil if you're holding it in two hands.
  • -1 recoil per point of STR bonus.
  • Maybe it's got gyroscopic stabilization or a huge muzzle brake or something? You can figure out anything special beyond that.
All of these apply after multiplying recoil for burst or full-auto fire. Whatever's left is a penalty to your attack roll.

That's fiddly as hell, fuck you Vayra

Yeah, it is, but you and your players only have to calculate this stuff once per gun. I recommend doing it in advance and building a table or generator or something. For example, here are some guns:

Beretta 92FS. Semi-auto, 9x19mm Parabellum (1d8, R1/2, 30'), 15 round magazine, iron sights, 1/3rd slot.
Colt Python. Semi-auto, .357 Magnum (2d6, R3/6, 30'), 6 round cylinder, iron sights, 1/3rd slot.
Remington 1900 Sawn-Off. Break-action, 12 gauge (3d8, R1/5 in two hands or 4/8 in one, 10'), double-barreled, no sights, 1 slot.
PPSh-41. Full-auto, 7.62x25mm Tokarev (1d8, R0/1/3, AP Light, 30'), 35 round magazine or 71 round drum, iron sights, 1 slot.
M4 Carbine. Select-fire, 5.56x45mm NATO (+1 to-hit, 2d6, R0/1/3, AP Light, 60'), 30 round magazine, red dot sight, 1 slot.
Remington 700. Bolt-action, .308 Winchester (3d6, R0, AP Medium, 400'), 5 round internal magazine (clip-loaded), 4x scope, 2 slots.
Dragunov SVD. Semi-auto, 7.62x54mmR (3d6, R0/3, AP Medium, 400'), 10 round magazine, 4x scope, 2 slots.
FN FAL 50.63 PARA. Select-fire, 7.62x51mm NATO (3d6, R1/5/9, AP Medium, 60'), 20 round magazine, iron sights, 2 slots.
Sako TRG-42. Bolt-action, .338 Lapua Magnum (3d8, R0, AP Heavy, 900'), 5 round magazine, 3-9x scope, 2 slots.
Mossberg 500. Pump-action, 12 gauge (3d8, R0, 30'), 5 round tube, bead sight, 2 slots.

Recoil values include stocks and stuff but don't assume two hands on a pistol, and are given for single/burst/auto where applicable. Slap that on a table somewhere for reference, and now you have it forever. 

When someone picks up a gun, they write the name down in their inventory and figure out their attack bonus with it and they're good to go. Here's how I'd write attacks with some of these down on my sheet for a 2nd-level Fighter with +1 STR and +0 DEX:

9mm Beretta 92FS, +2 ranged (-1 per 30'), 1d8 or double-tap (-1 if one-handed) for 2d8 and 2 ammo. 16/15 loaded, 15/15, 8/15 in spares, 83 loose rounds.

7.62x25mm PPSh-41, +2 ranged (-1 per 30'), 1d8 AP Light, 56/71 rounds loaded
            Burst +2 ranged (-1 per 30'), 2d8 AP Light, 3 ammo
            Full-auto +0 ranged  (-1 per 30'), 3d8 AP Light or cone at single damage, 5 ammo 

7.62x51mm FAL PARA, +2 ranged (-1 per 60'), 3d6 AP Medium, 20/20 loaded, 10/20 in spares
            Double-tap -2 ranged (-1 per 60'), 4d6 AP Medium, 2 ammo
            Full-auto -6 ranged (-1 per 60'), 5d6 AP Medium or cone at single damage, 5 ammo, note to self: don't do this.

A guy made this in his garage while on PCP and tried to rob a train with it and got shot and then I found it in the sand twenty years later, is it still safe to shoot?

Professionally made firearms that are frequently maintained have no chance of catastrophic failure. If you fumble your attack roll with one it jams and will have to be reloaded.

For everyone else, here's my post-apocalyptic quality table:
  1. Professionally made firearms fumble on 1. Roll a d20: 1 breaks; 2-20 jams.
  2. Decent quality firearms fumble on 1-2. Roll a d20: 1 explodes; 2-10 breaks; 11-20 jams.
  3. Jury-rigged firearms fumble on 1-3. Roll a d20: 1-5 explodes; 6-10 breaks; 11-20 jams.
Exploding firearms deal their regular single-shot damage to their wielder, with a DEX roll for half. Broken firearms can be repaired with gun parts and either an INT roll or a skilled armorer.



  2. It could have been so much more complicated too! Barrel length, impact of the stock on range, optics and red-dots.... but at a point, it *is* too fidly.

    1. My current rules for optics are something like:
      A proper red-dot or other close-range combat sight gives you +1 to hit within your first range increment, or a visible (to you) laser is +2 (doesn't stack)
      A proper scope lets you ignore range penalties out to whatever range it's good for (use a bit of fiat on this one)
      Future-tech (emitted light optics, smartgun systems) give +2 or more

  3. I like the armor HP rules, and the list of firearms is terribly helpful! This is perhaps the most comprehensive set of RPG gun-building rules I've seen... definitely gonna shamelessly steal bits of these! Thanks for sharing, can't wait to see more.

  4. This is excellent! It goes really well with the post-apoc gun generator. I do wish there was some way to determine price based on the weapon's stats, though.