These rules are a literal blast from my past being well over a decade old, from the days when I ran many many games of D6 Star Wars and my own D6 Star Wars / D6 Fantasy / Kitchen Sink inspired D6 Space Fantasy.   Cinema offering like Star Wars, and games like Dark Forces, X-Com (especially Apocalypse), and MechWarrior feature generous amounts of brightly colored rapid fire death and destruction, which I felt the D6 system needed a better approach to bringing to life.   I also wanted to give players even more play options at the table for ‘I shoot the guy’, without making automatic weapons fire into a complex minigame.   I also did not    

These rules have all been extensively playtested and to my mind work very swimmingly, with the caveat I like and encourage grand fireworks shows of automatic weaponry.   They also make automatic weapons in the hands of skilled marksmen a very awesome thing, and make blazing away a very good idea as the only drawback is the occasional burnt action reloading and needing extra ammo.  If you want a squad of stormtroopers dropped in a hail of blaster bolts in a single action by the mighty hero these are your rules!   If you want rules firmly grounded in reality . .  . these are probably not your rules.

D6 Autofire Rules

For all choices, the make by X over numbers can be decreased by whatever nifty widgets reduce recoil in the setting of choice.  Note, while the rules below mention hexes, hex maps are not required, simply use the abstract unit spacing representations of choice, yards, squares, hexes, inches etc.

Standard Autofire Attack – A normal attack to increase damage by attempting to land more than one round, it uses 1 action.

Declare how much ammo you will use before rolling.  

  • If you make the attack by 0-4, nothing special occurs, normal damage.
  • If make  the attack by 5 over, and fired at least 3 rounds, +1d damage.
  • By 10 over, and at least 6, +2d damage,
  • By 15 over, and at least 9, +3d and so on.  

This assumes an automatic weapon.

For semi-automatic and double-action and whatnot, see above but replace 5, 10, 15 and so on by 10, 20, 30 and so on.

Spray Attack

A normal attack with intent to better your chances of landing a hit through multiple rounds.

Declare how much ammo you will use before rolling, then get +1d to attack for every 3 rounds expended.

This uses 1 action and requires an automatic weapon.

Sweep Attack

An attack to sweep across a group of enemies in sequence to engage multiple targets.

Declare how many enemies attacking, all enemies must be in a row more

or less, though vacant hexes are acceptable. Declare the order the enemies are to be engaged, from left to right or right to left.  Ammo cost is 3 rounds per enemy and vacant hex between enemies.

Only one attack rolled is made, and compared against all targets.   The damage is base damage.

First target needs 5 over to hit, 2nd target needs 10 over, 3rd target needs 15 over and so on.  This uses 1 action and requires an automatic weapon.

Area Saturation Attack

This is an attack to engage multiple targets by filling the area they occupy with shear weight of rounds.rather than attacking them directly.

The hexes attacked must be contiguous and there is a minimum of 5 hexes.   Hexes may or may not be occupied, but the cost in rounds must be paid for each hex.

A single attack roll is made, and compared against all targets.

Three levels are possible.

  • Light – requires 3 rounds per hex.  The attack must be made by 10, and damage is reduced by 1d as attacks into the general area are less likely to hit individual targets and the damages may not be square hits or may be flying debris.
  • Moderate – requires 6 rounds per hex.   The attack must be made by 5, and damage is base damage.
  • Heavy – requires 9 rounds per hex,  The attack must be made by 0,, and damage is base damage.  Also, if the attack roll is 10 over, damage is base +1d.

Creating Automatic Weapons (Optional)

In D6 Star Wars and other D6 products, often a weapons nature as an automatic weapon is subsumed into its stats.    For instance, a Star Wars Light Repeating Blaster may do 6d damage have ammo capacity of 25, since 25 ammo is rather low for a squad support weapon in a setting where normal rifles have 100 round capacity, it is very likely that 6D comes from multiple shots at once.  You could say reduce the weapons damage to 5D and increase ammo to 100 and allow the weapon to use these rules.   


I haven’t used these rules in years . . . but, I could still remember them even before I found my old writeup!   I had a lot of fun with these back then, as these rules were used for years with many a hail of fire from a blaster rifle.   Since I am now a pretty dedicated GURPS player, I notice my old D6 rules split ‘make it easier to hit’ and ‘give chances for more damage’ into two separate options,  while in GURPS firing away with automatic fire does both at the same time!   Some of the inspiration for this comes from D20 Arsenal by Perpetrated Press, an excellent book for magical gatling guns and other fun toys for your D20 needs, a book sadly out of print.

As sometimes happens, a comment is too good to pass up and reply to in the comments section. Kallatari, who I believe knows of what he speaks, wrote in. His comments are in quote-blocks, and my responses or notes follow.

First, just wanted to say that what you’ve described is pretty much exactly how I’ve been gaming suppression fire in my games. The one exception is that I only did one attack to someone who entered the cone of fire, and not once per hex. I’ll be implementing that immediately.

That was a bit to keep things moving, keep the math to a minimum, and make each hex scary enough that it features as a deterrent in the player’s mind, since most times they’re not nearly as risk averse with their little paper men as they should be. Another way to go would simply be to figure out the transgressor’s “bullet exposure” and base RoF on that. But I really do like the per-hex method, because scary.

One thing I’ve wondered about, but never worried too much because it’s never really come up in my game, is what happens when the RoF divided by width gives an effective RoF that’s less than 1. It’s unlikely to occur when the target zone is centered on opponents at range. But, in a hypothetical situation, what if he made his cone 3 hexes wide 1 hex away (really desperate against that horde of zombies that just closed into melee range)? He’s basically covering a 180-degree cone, and the bullets that don’t hit would likely keep travelling quite a bit further away. So at 10 hexes away in this situation, the RoF is effectively a small fraction. Do we apply penalties to the effective skill of 6 (at which point, may as well declare an automatic miss). But what about the fright checks? I’ve now suppressed a 180-degree angle. Should there be a bonus based on the fraction (RoF of 1/2 = +2, RoF of 1/5 = +5?).

This seems as a good a judgement as any, and the two or three bullets per hex which norms to zero isn’t bad. I think that the usual cut-off for suppression fire is RoF 5 per hex, and since that gets a +1 for RoF in the usual rules and my alternate, using a lower RoF and having the shots be vs the minimum 5 or less wouldn’t be horrible. On the other hand . . .

Additionally, I’ve been starting to question why suppression fire is treated differently than any normal gunshots.

There is this. Technically, with the rules in Tactical Shooting how any near miss can induce a fright check, they’re not. At least for fear.

If I pick a single target and fire at his hex with Suppression Fire, I attack him with a maximum effective skill of (6 + 3 =) 9, even if my skill, say, 25. Even if I miss, he needs to make a Fright Check roll to not take cover. Finally, if any bullets miss, then I get to roll to hit anyone else who enters into the line of fire until my next turn.

On the other hand, if I pick that same target and fire 15 rounds directly at him then I get to attack with my skill of 25 + 3 = 28 (minus range penalty, etc.), which means a better chance to hit. But if I miss, he doesn’t have to make any Fright Check or bother to take cover. And if any bullets miss, I don’t get to attack anyone else who crosses the line of fire before my next turn.

I think there’s a case to be made for a few things here

(a) It’s important to hit the fear check for any missed shots. You might even say that the fear-check zone extends RoF bonus more hexes to the left and right of the area being fired into

(b) ANY use of RoF 5 or more creates a suppression line. For a direct-fire attack, that line is only one yard wide – a line, actually – but you get attacked as stray fire if you’re in the line when the bullets are fired, or with suppression fire if you cross that line later.

These are basically almost two identical scenarios with widely different game effects. I’ve therefore been contemplating – but haven’t yet implement – a rule where anyone in the line of fire of any gun shot (or laser beams, or lightning bolt spells, etc.) has to make a fright roll to not take cover, and that, if a bullet hasn’t hit a specified target, than there’s a “live fire” line of attack that anyone who crosses becomes a potential target. To me, All-Out Attack (Suppression Fire) just allows you to divide your shots over a wider area, reducing your chances of hitting in exchange for possibly affecting more people with fright checks.

Or what he just said. Yeah, this is fair if you can remember it . . .

My one hesitation is that it would possibly slow combat down in order to track all the lines/arcs of fire. But since I use MapTools for my combat, I don’t think it would be that complicated.

. . . and VTTs make it really easy. In fact, in Roll20 in the game described, that’s exactly what we did. Drew the cone of fire. We still had one guy run across it, but that was OK. It also makes the Teamwork or Standard Operating Procedure perks that much more useful, as I think one or both lets you cross suppression fire zones of your own team with relative impunity.

Last night in the Ceteri game, my character had the opportunity to unload an RoF 15 weapon in a narrow cone with something like five or six targets in it. It was a good chance to use the rules for suppression fire, which basically give you a 6+RoF bonus chance to hit there.

We use some generally agreed-upon rules – a combination of “this is the way we think the rules are actually meant to be applied,” common sense, and a slight tweak on the RoF bonus table.

The RoF Tweak

It’s not much. Look up the number of bullets fired on the Size and Speed/Range table, and read out the size modifier. Divide it by two, but round UP. Yes, up. That’s not the usual, but it works. Continue reading “Action Report: Suppression Fire in GURPS”

Over the past, in various GunDay posts, I’ve taken a look at the various Ultra-Tech weapons with a mind to both determining the feasibility of the weapons, and also checking their performance.

One of the more interesting posts, to me at least, was a ground-up redesign of a service pistol. The “ideal” pistol seemed to fire a 5.9mm projectile of unique engineered construction, which basically fired an advanced projectile that combined the AP capabilities of a tungsten tip along with a base that the tip gets pushed in to, which expands like the petals of the Ranger SXT modern-day JHP in order to enlarge the wound channel of the projectile to greater than 10mm, the threshold for pi+.

That gave us a projectile that wound up doing 2d (2) pi+, which wounds like a .45ACP and penetrates like a carbine, with a 20-round capacity that disappeared into a standard pistol grip.

Along the way, I also took a look at the Liquid Propellant (LP), Electrothermal-Chemical (ETC), and Electrothermal-Kinetic versions of various rifles, and found out (honestly, to my surprise) that all three were feasible with the right assumptions.

This particular article will take from all of those technologies in order to come up with a competitive TL9 rifle that’s an actual upgrade over TL8, and puts the right amount of power into the hands of the standard infantryman. Continue reading “Ultra-Tech Rifle: From the ground up”

GURPS telescopic sights work fairly simply. Each doubling of magnification gives a +1 bonus if you aim for a number of seconds equal to that bonus. So the “valid” scopes are x2, x4, x8, x16, etc. If you have a x1.5 scope, like the minor magnification on the Steyr AUG, you get nothing (+0 to Acc). If you have a x3 magnifier stacked in front of a collimating sight and use it as a telescopic sight, you get +1.

Them’s the breaks of breakpoints. Sometimes something is sub-resolution.

I was pondering based on an appropriately named thread on the SJG forums if there is a slightly different way to handle such odd powers: simply rewrite the Size and Speed/Range Table for your scope’s magnification, which is another way of saying calculate range penalties based on the effective range after accounting for magnification. Continue reading “Weak and Odd Scopes”

A brief digression into advanced conventional gun technology in GURPS Ultra-Tech.

There are two advanced technologies for firearms in GURPS Ultra-Tech. Liquid Propellant slugthrowers improves piercing damage by +1 per die (about 28%) with the boosted velocity version, and there’s a low velocity option that cuts damage in half, but we don’t care that much about that. Electrothermal-Chemical weapons increase damage by 1.5x. There are also Electothermal-Kinetic weapons, discussed in a Designer’s Notes for Ultra-Tech, Fourth Edition article, which are even more badass, multiplying damage by 2x.

What does that mean in terms of weapon design?

The Ballistics Model

My model – and remember, all models are wrong, some are useful – takes the peak pressure and maintains it for a certain distance down the barrel. This adds Pressure x Barrel Bore Diameter x Burn Distance in energy to the bullet: a straight-up application of energy equals force times distance. After that, it assumes that the propellant is all burned, and that the chamber and barrel and bullet form a pressure vessel, with the instantaneous pressure calculated using the ideal gas law. One can then calculate the instantaneous force at a given length down the barrel, and sum the product of that force over the distance – you’re performing an integration: E = Integral of F dx.

That’s wrong.

It just is. It’s not unusable, but it’s a simplification. It neglects the non-ideal component of the pressure equation, and it really ignores the fact that as the bullet is driven down the barrel, there is an opposing force of friction acting to retard the projectile. So while in real life, there’s an optimal barrel length after which more barrel is a hindrance to velocity, my model assumes that the bullet will continue to be accelerated pretty much forever.

That it falls off over distance, though, means that you need more and more barrel to actually get a GURPS-useful boost in velocity. So in practice, while it’s “wrong,” it’s not so wrong by so much that it doesn’t provide a useful and self-consistent model. Perfect? No. Usable? Yah.

But given the way that the program works, there are really only a few ways to add energy to the projectile. Continue reading “Ultra-Tech Firearms: Liquid Propellant and ETC”

In the last installment, a few of the basic weapons from the Rifles section of GURPS Ultra-Tech were examined. The basic premise was to see if the designed stats make sense, and evaluate them against an assumed mission statement: deliver 3d-6d injury after penetrating whatever armor the target is wearing. The typical foe was assumed to be a TL8 trooper wearing roughly DR 35/10d worth of hard/soft armor combination. This might be the TL8 Assault Vest + Trauma Plates (DR 12/5 + 23) or Advanced Body Armor (the generic form of DragonSkin, assumed to be as effective as the manufacturer claims).

Last time, we covered the basic Assault Rifle, and a derived hunting rifle firing the same ammo, the gatling carbine, and the 15mm payload rifle.

Today we finish up with some oddities, large-caliber specialty weapons that are either overdesigned or mis-applied in many cases. Continue reading “Gunday Continued: Ultra-Tech Rifles (Part 2)”

The rifle is the mainstay combat smallarm, given to every trooper. The current situation in the USA and the rest of the NATO countries have the primary projectile being the 5.56x45mm cartridge in various forms, and the “rest of the world” usually either uses the heavier and slower 7.62x39mm cartridge from the AK-47, or the small-caliber upgrade that is the 5.45x39mm from the AK-74. All of these more or less eke about about 5d: The 5.56x45mm M193 cartridge (the 55-grain/3.5 gram version) basically defines what 5d is in GURPS (and also happens to be about right – that bullet/rifle combo – the 55gr projectile at about 1000m/s from a 20″ barrel – punches through about 1/4″ of mild steel). The AK-47 is given 5d+1 in High-Tech, and the AK-74 a “downgrade” to 4d+2.

My own calculations are slightly different here, but only slightly. The 7N6M 5.45x39mm is a 53gr projectile at 880m/s, for 16.8 points of damage: 5d-1 is probably the best fit here; the penetration of 6mm of armor plate at 300m that is claimed (and the Rockwell C core hardended to Rc 60) might speak to a 1.5 armor divisor if such were still used. The AK47 bullet comes in at 19 points of damage, or 5d+1, as listed, at 122gr and 722m/s. My M193 comes in hot based on energy and diameter – it should penetrate for 19.3 points of damage, but empirically does not do so; some quick calculations show that the bullet is probably operating at close to it’s maximum coherence energy, so much kinetic energy in the projectile that the bullet itself can’t take the impact. Either that or (which is more likely) my formula is off by a bit. Either way, all of these come in at roughly 5d.

All that being said, what is enough injury? 3d injury is enough to take a regular Joe with 10HP and have them risking a KO; 6d is a death check. If your foes are human – and that’s the default assumption here – anything more than that is for two things: hitting at range, because you need to reach out and touch someone there, or punching through armor.

For the second, in GURPS, the best way to get armor defeat into the design is by bullet construction, that is to say, armor divisors to knock the protection down, followed by enough kinetic energy to defeat the remaining DR and the threat. For range, again, bullet construction is key, as high aspect ratio projectiles will hold their velocity (and thus damage) better. Retaining full ballistic performance (in terms of the GURPS 1/2D metric) to somewhere between 300 to 500m seems to fit the bill for the man-portable battlefield weapon category, and that’s basically the sweet spot for the 5.5mm type weapons, and the 7.62x39mm also fall in that range – my calculations put all three in the 400yds 1/2D range. That’s because of the relatively low sectional density of the 5.45mm round, and the high cross section of the 7.62mm one.

Battlefield Personal Weapon: Goals

So, the goals here for evaluating the old designs, and developing new ones, will be to improve on the 1/2D range (which also means that velocity loss by using shorter barrels will be somewhat mitigated) into the realm of the older battle rifle range (500-700yds), provide for a (2) armor divisor through bullet design (which will almost certainly mandate some sort of high-density core), and deliver 3d-6d injury after penetrating body armor.

The question of how much armor seems a legit one: modern trauma plates with a woven fiber armor backing will frequently provide about 10d worth of protection – DR 35 – from the plates alone, backed by the woven armor. The typical threat that this is gauged against seems to be the .30-06 M2 AP bullet, which hits for about that penetration.

So any design that’s notionally TL9 should probably stand up well against that level of ballistic threat.

Special Applications Rifles: Goals

The other set of weapons that will exist are what one might call rifles for special applications. Sniping, anti-materiel usage, and payload weapons all fit the bill here. These will put a premium on accuracy, as their usually hefty ammo does not lend well to carrying a lot of it. It will also be a place where versatility will come into play, as the projectiles start to get large enough that explosive, homing, and other special devices become practical and perform well.

Let’s Get To It

That’s a lot of pre-amble: let’s see how the rifles in the book do.

Ultra-Tech Standard Rifles

The book as written provides seven rifle-class weapons. All are assumed to be caseless, and they come in a few flavors. There’s a 5.7mm weapon that fires the same projectile as the PDW discussed in the prior write-up. There are two 7mm designs, two 10mm, a 15mm anti-materiel rifle, and a 25mm payload rifle. Let’s break ’em down. Continue reading “Sunday is GunDay: GURPS Ultra-Tech Rifles”

Idle conversation on the Discord chat about a full-auto .50 BMG rifle (as opposed to a machinegun) led to the comment that for sufficiently strong and large races or creatures, they really should be kitted out with battle rifles in sufficiently impressive calibers.

I mean, why wouldn’t a large-enough race make a rifle capable of firing 14.5mm KPV rounds?

Now, it’s been a while, but I don’t think a character’s ST has any impact on a weapon’s stat line.

Let’s look into fixing that. Continue reading “Rcl and ST in GURPS”

Continuing with my exploration of redesigns of the slugthrowers presented in GURPS Ultra-Tech, the next step is to look at submachine guns (SMGs), and Ultra-Tech (sensibly) includes Personal Defense Weapons (PDWs) in this category. However, if one looks at my prior articles, a raw-stats look at the four Ultra-Tech pistols, as well as some heavy design and less-heavy mechanics look at a ground-up TL9 pistol concept, you can see there’s already been some groundwork laid that should influence the following examination.

Prior Art

What concepts have been introduced?

  • TL9 10mm ammo has a base damage of 3d+2 pi+ out of a 4.5″/115mm and delivers around 1,100J of energy
  • There is a family of combustible case 7.8mm ammunition that deliberately targets GURPS breakpoints to deliver 2d+1 pi damage from an 85mm barrel, and 2d+2 pi from a 145mm barrel as a service pistol
  • An integral suppression system probably weighs about 0.1 lbs per 50mm of barrel
  • There’s a high-tech ammo type that was shown as an example of a TL9 combustible case or caseless telescoped cartridge. It uses a long bullet that expands to 75% of the length of the bullet in diameter. Call this CCTAPX (see-tap-ex) for combustible-case telescoped expanding. It’s cost per shot, though, is probalby 10x normal.

What is an SMG/PDW, anyway?

Ultra-Tech uses a fairly conventional classification of weapons, putting SMGs (which it defines as 10mm full-bore pistol rounds from a rifle-shaped platform) and PDWs in one group . . . but classifying short-barreled rifles, the carbine family, along with rifles. Continue reading “GunDay: GURPS Ultra-Tech SMGs and PDWs”