Do Effects/Qualities stack with one another (primarily Burst related)

Does a weapon with Piercing and Spread apply the Piercing to each location hit or just the primary one?

Does Spread affect multiple targets if paired with Burst?

Does Persistent apply to multiple targets hit by Burst?

Does Radioactive apply to multiple targets hit by Burst?

Does Stun apply to multiple targets hit by burst?

What about multiple targets hit via Perk (such as Gun Fu)?

I’ve been playing it that Vicious, which directly modifies the damage, applies to other targets and other locations (via Spread) but all other Effects affect only the first attack and location.

I think people will say that Breaking and Piercing stack with Burst, Spread and Persistent, but nothing else stacks.

I have been playing that nothing stacks. That may seem odd, but when you see what a Flamer with full mods, Pyromaniac 3 and Size Matters 3 can do, (lots of Vicious adding to every Burst, Persistent and Spread) it’s too much.

Likewise, a maxed-out Combat Shotgun with Rifleman 2 and Shotgun Surgeon getting Piercing 2 on Spread equates to quite a lot of damage. (And same with a Scattergun Laser Rifle and Rifleman 2.)

Or consider if Persistent stacks with Burst on an Improved Incendiary Institute Laser with Commando 2 and Laser Commander 2. It’s 11 Dice Damage usually rolls 9 Damage and 3 Effects. That’s an average of 144 total damage to 4 targets from 1 attack:
9 initial + (3 × 9 Persistent) + (3 Bursts × [9 initial + (3 x 9 Persistent)])
With a Rarity 2 weapon. And level 6 Perks.

I’m okay with there being a weapon/build that can do big damage, but most of these mods and perks are available below level 11.

I’m okay with Vicious “stacking” since it’s modifying the raw damage output. Its the others that I’m less convinced work.

So like a weapon with Vicious 1 and Burst that rolls 1,1,2,4,4,5,6 would do 8 damage to each target. A weapon with Spread and Burst that rolled the same would do 6 damage to the main location, 3 damage to two other locations and then 6 damage to other targets. A weapon with Piercing 1 and spread would do 6 damage ignoring 2 DR to the main location and 3 damage to 2 others but with full DR.

One could make the argument that Burst only says you hit additional targets and you should roll the damage separately for each target but I tried that and it’s just tedious with some weapons.

Rolling individual Bursts or Spreads would be unthinkable with big dice pools. High level builds could be rolling 15+ dice. Imagine rolling 15 Spreads for 1 attack.

Yes, at level 1 with un-mod-ed equipment, it all works smoothly. Damage Effects only go crazy when the dice go up.

Consider a Muzzled Quick High Capacity Recoil Compensated Automatic Combat Shotgun with Commando 2, Quick Hands and Shotgun Surgeon (Damage 4+2, Fire Rate 7x2, Burst, Piercing 1, Vicious), against a big group of things with 10 physical DR on every Hit Location. The 20 Damage Dice will roll an average 16 damage and 6 Effects.

EDIT: Oops. Automatic Combat Shotgun doesn’t have Vicious. Calibrated Combat Shotgun has Vicious, but no Burst. So, these numbers aren’t for a real weapon, but show how these Damage Effects can add up.

First Target = 16 + 6 Vicious - (10 DR - 6 Piercing) + 6 Spreads × [([16 + 6 Vicious] ÷ 2) - (10 DR - 6 Piercing)]
= 18 + 42 Spread
= 60 HP loss to first target
6 Bursts with Spread = 6 x 60 = 360
6 Bursts no Spread = 6 x18 = 108

One-shot-ing a Mirelurk Queen and her 6 friends. With one attack. With a build available with level 6 Perks.

Now without any stacking:
First Target = 16 + 6 Vicious - (10 DR - 6 Piercing) + 6 Spreads x [([16] ÷ 2) - 10 DR]
= 18 + 0 Spread
= 18 HP loss to first target
6 Bursts no Spread = 6 x (16 - 10 DR) = 36

This still does enough damage to inflict Injures on all 7 human-sized targets, but doesn’t break the game.

I’ve seen it suggested to apply Piercing to Spread, but not Vicious to Spread. But, for me, a Scattergun Laser Rifle with Laser Commander 2, Mister Sandman, Rifleman 2 and using the Accurate Quality does crazy stuff.

I was under the impression that you needed to “spend” effects to activate them when the trigger says : “for each effect rolled”

Say you rolled 1, 1, 5, 5, 6 on an attack with stun, spread, piercing 1 and vicious, I thought the attack would indeed stun but you’d need to spend the 3 effects between piercing, vicious and spread. So you might spread 1x a piercing 1 and vicious 1 or spread 2x a piercing 1 etc

I think the game would be more balanced that way anyway.
I think I’ll even say that each keyword cost 1 effect to trigger and those who say “for each effect” you are simply allowed to trigger that same keyword more than once.

You could HR it that way but it’s not the RAW. Rolling a lot of effects on something with Vicious and Piercing is a bad, bad day for the target.

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I agree that unless Modiphius comes out with something in a new errata, Rules As Written is that Effects and Qualities stack. It just doesn’t work for my group.

Different GMs are going to value different things. I’m looking to bring my group from level 1 to level 25 over the course of 200 sessions. That means character death, damage to bosses and high-level balance are all very important to me. Effects stacking is just too much chaos for that.

Certain high rolls doing big damage is fine, but if you look at Burst, Persistent and Spread stacking with big dice pools, it’s huge damage even on average rolls. And for what? To respect some ink in a book? I’ve never had a character complain that a weapon did reasonable damage. Nobody has ever said to me, “This game would be so much better if one super mutant’s flamer killed us all with one attack.”


If you’re looking to bring your group from level 1 to level 25 over the course of 200 sessions, do you mind sharing some of your other HR ideas (assuming you’re using them)? I really like some of the ideas in this game, but certain mechanics feel like the simply haven’t been play tested. I have my own list of house rules I’ve come up with I’d be willing to share and get feedback on; I haven’t run a campaign yet so I’m entirely green.

If not, then understandable and all’s well - hope your campaign goes well!

Edit: In your most recent example, correct me if I’m wrong, but it looks like Quick Hands is being used here, which might be the culprit? I need to see how the math works out if you let everything stack but DON’T use Quick Hands (I’m planning to HR Quick Hands to something more reasonable than x2 Fire Rate).

Edit 2: My quick example with everything stacking, no Quick Hands, gave about 15 damage to each target (no Spread): 15-6 DR = 9 to each hit, which means critting every enemy (ouch!). If apply Spread only to first target, then first target takes total of 26.11. If apply spread to all targets, they all take 26.11. Hmm…

That is interesting, as this “stacking of Effects”, or the triggering of all applicable Qualities by the number of rolled Effects on the damage dice never changed across all the 2d20-based RPGs.
It is a core concept of the damage models of 2d20 games with the exception of Dishonored and Dune, which both don’t use damage dice at all.

So what exactly does not work for your group?
That dangerous weapons (with many qualities that could be triggered by Effects) are actually dangerous?
That works both ways - for NPCs and for PCs the same. - And it did work since the very first 2d20 RPG, Mutant Chronicles, was published.

I actually finally got around to running our first game, and so far, we did everything RAW. Well, almost everything - my group immediately noticed that AGI 9+ giving Defense 2, all decided to make AGI 9 characters, and were all vocal about really disliking this mechanic.

So we just house ruled that you’re Defense is 1 no matter what your AGI is, one person kept AGI 10 (for Gun Fu), and we had a blast.

We didn’t house rule anything else, let the weapon effects stack, and all was well - though they are low level currently.

That is my impression, too. - It makes the decision a “no brainer”, a “must have”, as +1 Difficulty for others to hit you is quite an advantage that most players don’t want to miss.

In most other 2d20 games the base difficulty to hit someone is a D1, modified by range for ranged combat or by weapon reach (in Conan) for melee combat. But keeping it at D1 is usually fine.
In STA and some other games, ranged combat usually has a base difficulty of D2, which I find fitting for Fallout, too. In those games melee combat is always resolved as an opposed test, which in itself includes a varying difficulty depending on the ability and the dice rolls of the opponent.

The threshold of AGI 9+ for +1 Difficulty to be hit is not a good rules design element, in my view.

Why do they not like having a Defense 2?

I don’t think they would mind if I just handed them out Defense 2 for free. I think the issue is that everyone was feeling somewhat forced to take AGI 9 or higher to get it, which reduces build variety.

The real question is whether Fallout works better at D1 or D2, in general. I opted for D1, for now, as I tend to be conservative in this regard - I don’t want everyone missing each other at low levels (ie, at TN11, you have a slightly better than 25 % chance of hitting D2 using 2d20).

But maybe it works better with D2, I don’t know. But none of us like having AGI 9+ as a threshold, regardless.

Through playtesting and two different campaigns I’ve had a few people take AGI 9 and many who didn’t, actually the majority don’t. Attribute points are somewhat limited and some player don’t want to hamper themselves in that way. YMMV.

That’s not to say that DEF 2 isn’t a huge benefit. It absolutely is but I have found that when that DEF 2 gets hit it hurts a lot because they tend to not have the END or LCK or Health to stand up to actually being hit.

In a combat heavy game, or one that’s perceived as being combat heavy people are going to gravitate towards the AGI 9 but that’s generally in direct response to the game they’re playing. Over the course of things I’ve played with about 20 different people and only 4 of them opted for the AGI 9 even taking in to account raising attributes via Perks.

That’s fair. My group are all focused on combat and all wanted to make characters that are good at it, but still different from each other. All of them said they felt like they needed to take AGI 9+ or they would be hampering themselves needlessly. And thus, they didn’t like how samey it felt.

I personally do sympathize with them - with TN 11 using 2d20, you’re talking about 75 % hit chance vs AGI <9 or 25 % hit chance vs AGI 9+. With the house rule were currently using, we have one player with AGI 7 and another with AGI 8, and neither of them feel crummy about it.

It may be that AGI 4 vs AGI 9+ is a different story, but that still feels restrictive as you’re either going all in or nothing.

I also understand that, with everyone at D1 instead of D2, the game is “harder,” but really that just means I can get away with having fewer raiders/etc in a fight for comprable difficulty, and so the combat itself is on a smaller scale and takes less time, which we’re also happy about.

Just one group for my sample size, I haven’t run any other games yet.

Edit: I should also point out that literally everyone in my group is a min maxer, no matter what system we play, so it’s probably not your normal/average group.

The difference between a D1 and a D2 isn’t as big in other games where the GM has more Momentum/AP but Fallout seems to have both reduced the amount a GM has and has so many rerolls for everyone that complications are much rarer. In Fallout a +1 difficulty is a big thing and I 100% don’t blame combat characters for taking the Agi 9 for both the DEF increase and the increase to hit.

I will say, it doesn’t surprise me that many groups seem to run this game RAW, some with their own HRs that vary considerably, and they still enjoy the game game plenty regardless.

I feel like this system (this is my first 2d20) is flexible enough to allow more than one way to play it, and it just works (no pun intended).

Spelled out, my issues are:

  1. These weapons with many Damage Effects and/or Qualities (or powerful combinations of them) appear at fairly low level. The huge jump in average damage means that enemies have to be boosted to maintain balance. Low-level enemies and gear are rendered useless, and the point at high level when everything becomes an insane bullet-sponge comes much faster. The early, low-power phase of the game is cut off for no good reason.

  2. In the book (and even in the homebrew weapons I’ve seen) these dangerous weapons are reserved to Small Guns, Big Guns and Energy Weapons. Even if Damage Effects don’t stack, there has to be a lot of homebrew-ing done to make Explosives, Melee Weapons, Throwing Weapons and Unarmed builds competitive at high level. Damage Effects stacking makes this much worse.

  3. Damage Effects stacking makes each Effect rolled on the dice much more consequential. If Persistent, Piercing and Spread can be added to a Burst Damage Effect, then each Effect rolled on the dice could become 10+ damage. That’s very swing-y and randomized. With a weapon like that, I’d have no idea if this enemy will leave the party unharmed or kill them all in one shot. That’s too unpredictable for a very long-term game where character death and boss death should be consequential. There needs to be randomness, but that’s way too much for me.

I acknowledge that Modiphius games have Damage Effects stacking. And I think that for a chaotic one-shot, very random, dangerous weapons are fun. But I don’t see what a Flamer maxed-out without any crafting Perks at Level 3 (because of the Scrapper Perk) doing hundreds of damage adds to my game.

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This thread got pretty de-railed. The question was do Damage Effects stack? And I think the answer is a resounding yes in RAW. Which I don’t like, but that’s me.

But since you asked me directly, I have a whole WorldAnvil page to share my house rules with my players. There are a lot, and I don’t explain my thinking in the list, but here it is:

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