Explosives Question, Am I reading the rules wrong? Options

[AppliedCheese]

Suffice to say I have some players who are considering using an IED in one of their runs. Its about 2 kilos of TNT with a pressure plate/push-in detonator. A classic homemade mine.

Sounds like it should be pretty effective.

But reading the rules it says that it should have a DV of Sqrt Kilos * V. So, with TNt rated at 4, 2 kilos of the stuff should have a DV of 5.6 (rounded to 6) if it goes off right underneath a target. And it halves armor. That should be roughly enough to...mildly inconvenience someone.

In contrast, a high explosive grenade has a DV of 10.

So, what am I missing here? Is there a net hits process I'm ignoring? A special non-resistance? Extra damage from fire or concussion? Because what seems like it should tear a leg off is roughly the same as a 5.56 flesh wound how i'm reading the rules...

[Aku]

Well, you add 1 to the effective rating for each hit on the Demo+ logic test, as well..

[Eisenbeiß]

You missed "Each hit on the Demolitions + Logic Test adds 1 to the explosive’s effective rating" on the same page.

Edit: Too slow. (IMG:style_emoticons/default/wink.gif)

This post has been edited by Eisenbeiß: Oct 14 2010, 09:44 PM

[Yerameyahu]

Why does it halve armor? I forget. Unless you're talking about the 'attach directly to target' rule, which doesn't apply.

[Brazilian_Shinob...]

If you are using the Arsenal rules, check my sig. I've made a java app that calculates all the stuff for you.

[AppliedCheese]

Ah, handy. Thanks for the replies.

As for attach directly, I figure that stepping on a pressure plated bomb is as close as your going to get to direct without adhesives.

[Yerameyahu]

(IMG:style_emoticons/default/smile.gif) That's the point, though. It's not close enough. It's a penetration bonus for demolition setups, where you *do* use adhesives. I mean, if you wrap a cutting charge around a guy's neck, yes. (IMG:style_emoticons/default/biggrin.gif)

[Karoline]

(IMG:style_emoticons/default/smile.gif) That's the point, though. It's not close enough. It's a penetration bonus for demolition setups, where you *do* use adhesives. I mean, if you wrap a cutting charge around a guy's neck, yes. (IMG:style_emoticons/default/biggrin.gif)

Indeed, though if it is buried in the ground/has a backplate, you could claim chunky salsa since the blast can only go up instead of up and down, which would double the damage, unless it already has something about directional explosions in there, don't remember all the demo rules off hand.

[Neraph]

Indeed, though if it is buried in the ground/has a backplate, you could claim chunky salsa since the blast can only go up instead of up and down, which would double the damage, unless it already has something about directional explosions in there, don't remember all the demo rules off hand.

Ooooh, I like that thinking.

Alternatively, what would happen if you cook up your own Ex-Ex rounds at home? What would the "net hits" on the Test look like, or does that even work? Can we get +12P/-1 AP Ex-Ex rounds?

[Karoline]

Alternatively, what would happen if you cook up your own Ex-Ex rounds at home? What would the "net hits" on the Test look like, or does that even work? Can we get +12P/-1 AP Ex-Ex rounds?

I doubt it, as the net hits are a bonus based on your ability to set the explosives properly (Weak point in the structure, adding in some shrapnel for personnel, whatever), and so wouldn't transfer over very well to bullets. That and I'm sure companies would put out at least +2 ex-ex rounds if it was that simple.

[Neraph]

That and I'm sure companies would put out at least +2 ex-ex rounds if it was that simple.

They used to. Then were the days of Errata.

[Karoline]

They used to. Then were the days of Errata.

I know (IMG:style_emoticons/default/nyahnyah.gif)

They forgot to do basic math in trying to balance the different types of ammo, and didn't realize that the ex-ex ammo was twice as good as APDS as originally printed.

[thetrav]

We've just come across this one in the game I'm playing as well.

So a HE grenade does 10 damage.

Basic commercial explosives at rating 3, and a fairly average demo expert gets effective rating of 6, so to reach parity with grenades he's going to have to place about 3kg of the stuff... That's a LOT of explosives, and about 3 times the cost of a HE grenade.

That still doesn't seem right to me just in terms of damage output.


I note that on destroying barricades, they get 2x their armour unless the damage is from explosives, does that include HE grenades as explosives?

I also saw in the explosives section that armour is not counted if the explosives are directly attached. Does this count for barricades? By default I thought no, but I'm doubting that because they just don't seem at all reasonable to use instead of grenades

[Yerameyahu]

Really, it *only* counts for barricades (barriers). It's the entire point of demolitions. If you have someone that you have time to attach explosives to, you could kill them with or without the armor-halving (not armor-ignoring, btw).

Demolitions is for destroying ('demolishing') barriers. It just happens that it has the *secondary* use of mines and booby-traps.

Also, that grenade is F, while the Commercial demolition explosives are R. Yes, grenades are probably way too cheap, especially since they all come with impact, timer, and remote detonators. (IMG:style_emoticons/default/smile.gif) 'Game balance'?

[thetrav]

I have a specific scenario to run past you.

We're in a 3mx3m underground corridor that runs up to and ends at a security door.

We want that door out of our way.

We have 7 kg of commercial explosives and a demolitions guy who's not great but ok.


If we strap the explosives to the door at approximately its center, and the demo guy gets 3 successes, then we're looking it:
(3+3)*SQRT(7) = 16DV

chunky salsa means it's bouncing off 4 surfaces, each about 1.5 meters away, so that's another 40 points of damage from bounce back

so 56DV of damage, ignoring armor, on a security door of structure 9 means 6 point something square meters of door blown away, and keep well back.

Is that a correct "hypothetical" calculation?

[Yerameyahu]

Well, I don't see how chunky salsa is relevant here. Any reflections would be parallel to the door, not against it. (Aside: chunky salsa is a total conceptual mess, whether you're using game balance or real physics. (IMG:style_emoticons/default/biggrin.gif) )

Once again, there's no 'ignoring armor': it's *halving* armor.

So, that's DV*2 (explosives against barriers) and halved-doubled armor (i.e., 8 ). That gives 32DV-3(ish)=29, 3 square meters. Also, a large shrapnel-y blast on the other side (not 32DV, though: 16, -1/m.) I think. It's all very unclear. (IMG:style_emoticons/default/wink.gif)

Do check out the 'advanced' demolitions rules in Arsenal, if only for the mental exercise of all their crazy math. (IMG:style_emoticons/default/smile.gif) Also, I think it contradicts the book in a few places? Bleh.

[thetrav]

Isn't chunky salsa relevent anywhere there is a space that channels the blast?

If it cant go up down east or west, then the force exerted north and south is going to increase isn't it?

from page 167 of the 20th anniversary core book:

Resolve the damage resistance test by rolling the barrier’s Armor x 2. Against Indirect Combat spells and explosives attached directly, barriers roll only their Armor rating.

and page 325

When attached directly to a target, the target’s armor is halved, otherwise the explosive is assumed to have an AP value of 0.

Ahh, I see, those two statements are referring to the same thing, as opposed to "stacking" and you are correct, I misread/misremembered halving as ignoring


After all the pain I had of trying to work out the modification rules and the bizarre stat of the minigun (identical to LMG but spin up and uses more ammo), I'm fairly reluctant to use arsenal for anything else

[Yerameyahu]

Well, using more ammo is kinda the point: more bullets is wider Wide Bursts or narrower Narrow Bursts. (IMG:style_emoticons/default/smile.gif)

One confusing bit is that (I think) Arsenal doesn't do the 'DV*2' bit that SR4A clearly does. My theory is that SR4A assumes you're getting the x2 bonus from Charge Placement in Arsenal. *shrug*

Re: chunky salsa, is also depends how strong those walls are. Assuming they're strong enough, though, the blast would logically be channeled. However, AFAIK, logic is not a relevant issue with these rules. (IMG:style_emoticons/default/wink.gif) The shockwaves reflect in straight lines only.

Anyway, in the above example, 3 square meters is plenty. 7kg is a lot of explosives (about 2.5kg more than you really need), and you're getting the +3 bonus from taking the time to set the explosives (that's what Demolitions skill is; Logic + Demolitions of 9 is pretty decent, or did he just roll high?). If you just slapped the brick against the door and pushed the button, it'd only be half the effective rating.

[Summerstorm]

On the other Hand, there are some silly other effects possible (on high-mass bombs - well, i guess there SHOULD be)

Here in this thread i have made some BIG bombs:
http://forums.dumpshock.com/index.php?showtopic=32581

But yeah, on "low-mass" bombs the normal grenade is VERY much the best and can not be replicated.

[Yerameyahu]

Well, presumably the grenades are assembled by a *really* high Logic + Demo. (IMG:style_emoticons/default/smile.gif)

[Udoshi]

So a HE grenade does 10 damage.

Part of the problem with current grenades was 4A's Nerf to anything with scatter.
Basically it was doubled across the board, and the distance-reduced-per-net-halved.
The icing on the cake, though, is net hits no longer add to damage. They ONLY reduce scatter. Previously, once scatter was reduced to zero, net hits carried over to DV like they do for every other weapon in the game.

So yeah. Demolitions is pretty much better in every way.

[KarmaInferno]

Use Dragonfly explosive drones. No scatter.

(IMG:style_emoticons/default/smile.gif)




-k

[TheScrivener]

Not strictly on topic I know, but I'd just like to say I'd never really read this paragraph before:

Placing the explosives inside the structure is also a form of
tamping, but requires a lot of eff ort. (Note that to qualify for this
multiplier, the explosive must be actually inside a wall, pillar, or
similar—if it is in a room inside a building, it does not count as
being “inside” the structure unless the whole room is somehow
fi lled with explosives.)

My group's demo specialist is about to have a new goal in life.

[Brazilian_Shinob...]

thetrav, check my sig. I've made a Java app just for this. You put the modifiers, explosive rating (counting sucesses), barrier, etc and its output shows the damage value and size of the hole.

[Karoline]

Fun fact: Tamping can be accomplished with Styrofoam (IMG:style_emoticons/default/biggrin.gif)

Also, the part of the equation for the HE grenade you're forgetting is shrapnel.