Need help for Explosives rules

[garrowolf]

I apologize if this subject bothers someone, especially after the bombings in NY.

I'm working on explosives rules for my Nexus D20 rules. I need some help. My rules use a general range scale instead of range increments and I want to convert explosives to the same chart. This is what I have so far. I need help filling in or correcting the rest.

This is my range Table
[FONT=Verdana, sans-serif]Range [/FONT][FONT=Verdana, sans-serif]Table[/FONT][FONT=Verdana, sans-serif][/FONT]
[FONT=Verdana, sans-serif]Ste[/FONT][FONT=Verdana, sans-serif]p[/FONT][FONT=Verdana, sans-serif] [/FONT][FONT=Verdana, sans-serif]([/FONT][FONT=Verdana, sans-serif]5ft/1m[/FONT][FONT=Verdana, sans-serif])[/FONT][FONT=Verdana, sans-serif] [/FONT]
[FONT=Verdana, sans-serif]Close Quarters [/FONT][FONT=Verdana, sans-serif]([/FONT][FONT=Verdana, sans-serif]30ft./10m[/FONT][FONT=Verdana, sans-serif]) - [/FONT][FONT=Verdana, sans-serif]Inside a room. [/FONT]
[FONT=Verdana, sans-serif]Short [/FONT][FONT=Verdana, sans-serif]([/FONT][FONT=Verdana, sans-serif]120ft./40m[/FONT][FONT=Verdana, sans-serif]) - [/FONT][FONT=Verdana, sans-serif]Across the street ranges [/FONT]
[FONT=Verdana, sans-serif]Medium [/FONT][FONT=Verdana, sans-serif]([/FONT][FONT=Verdana, sans-serif]240ft./80m[/FONT][FONT=Verdana, sans-serif]) - [/FONT][FONT=Verdana, sans-serif]Down the street a few city blocks [/FONT]
[FONT=Verdana, sans-serif]Longbow [/FONT][FONT=Verdana, sans-serif]([/FONT][FONT=Verdana, sans-serif]540ft./180m[/FONT][FONT=Verdana, sans-serif]) - [/FONT][FONT=Verdana, sans-serif]Across a field [/FONT]
[FONT=Verdana, sans-serif]Long [/FONT][FONT=Verdana, sans-serif]([/FONT][FONT=Verdana, sans-serif]1050ft./350m[/FONT][FONT=Verdana, sans-serif]) - [/FONT][FONT=Verdana, sans-serif]Across downtown [/FONT]
[FONT=Verdana, sans-serif]Extreme [/FONT][FONT=Verdana, sans-serif]([/FONT][FONT=Verdana, sans-serif]2400ft./800m[/FONT][FONT=Verdana, sans-serif]) - [/FONT][FONT=Verdana, sans-serif]One end of a small city to another

So the idea is that each explosive would have a range listed for the Kill Zone, Injury Zone, and Secondary Effects (pressure wave/glass/etc.)

So these are the types I am working on:
[FONT=Verdana, sans-serif]Grenades, Mortars, Satchel Charges, Suicide Bomb, Pipe Bomb, Suitcase Bomb, Compact Car Bomb, Full Sized Car Bomb, Van/U-Haul Bomb, Tractor Trailer Bomb [/FONT]

So for instance Grenades have a small kill zone (step), and have an injury zone of close quarters. I'm not sure of the secondary zone.

Anyone know any of this? I've tried finding this on line but the most I can find is the secondary zone ranges.


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[garrowolf]

opps

 

[garrowolf]

Anyone who was in the military who might know this?

 

[Celebrim]

Most of this can probably be extrapolated by looking up the weight of the high explosive charge in the weapon you are stating out. Wikipedia and Yahoo! have a lot of the answers you are looking for.

Each 8 fold increase in weight presumably doubles the range of the weapon. For instance, a 155mm round contains about 100 times (12+ lbs) as much explosive as a grenade (2 oz). So the blast radius is going to be at least 4 times as wide. A grenade has a blast radius of about 15 feet, and throws random shrapnel over a radius about 45 feet. So we'd expect a 155mm shell to have a blast radius of at least 60 feet, and to throw shrapnel at least 180 feet. Looking at the numbers, the military suggests that 50% of persons within 150 feet of a 155mm shell detonation will sustain serious injury, and puts the safe distance at 300 feet.

If you want high accuracy you are going to need to be more granular than your table is, but...

Presumably, a grenade would be something like - Step (2d6+6, Ref DC 18/save for half)/Close (1d6+3, Ref DC 16/save negates).

And a 155mm HE round would be something like - Close (8d12+24, Ref DC 22/save for half)/Short (4d12+12, Ref DC 20/save for half)/Medium (2d12+6, Ref DC 18/save negates). Note, if you don't mind being as unheroically lethal as modern weaponry actually is, you might also have a Step range on the 155mm of 16d12+48 no save allowed unless you have at least 90% cover. This lets you realistically deal with the damage to structures and other objects.

Above assumes you are using typical D20 hit point based injured system.

 

[garrowolf]

What I was planning on doing was having a Kill radius meaning anyone not in power armor is gone, an injury radius which will depend in how much armor or cover they have, and then the secondary radius which covers minor injuries.
As for the system I'm using a wound level system.

 

[Celebrim]

What I was planning on doing was having a Kill radius meaning anyone not in power armor is gone, an injury radius which will depend in how much armor or cover they have, and then the secondary radius which covers minor injuries.
As for the system I'm using a wound level system.

Is this primarily for a wargame or an RPG?

Overpressure/concussive waves in most weapons are not particularly lethal, and op analysts as early as WWI learned that if the human body wasn't in direct line of a projectile, it could survive an amazing amount of momentary pressure. Guys in foxholes or other depressions might have their ear drums busted and suffer mild concussion from a nearby artillery shell, but unless we are talking about something like a fuel-air explosive the kill radius of a weapon is hard to define.

Anti-personnel weapons generally are designed to produce a cloud of fragments that does most of the killing beyond the first few meters. These clouds are typically not symmetrical, particularly in older primitive shell designs, and very quickly develop gaps. A typical older 155mm HE anti-personnel shell might produce 4000 fragments. At a radius of 15 feet, that's a density of 5 fragments per square foot - ripping apart any fleshy thing in its way. But at a distance of 75 feet, that's only 1 fragment every 20 square feet. It's possible that a person at that distance would get missed by metal fragments entirely, suffering only from the blast wave and secondary debris. The person might still be seriously hurt, especially if they were standing up and unprotected, but my point is that blasts aren't symmetrical and after a certain point how badly you get hurt is extremely random. You could get nothing, and the guy standing next to you could have his head completely taken off.

 

[garrowolf]

Correct. It would depend on what you are doing in the secondary blast radius. You may not take any damage. However you would have to check for it.

 

[Storminator]

I prepared explosive rules today

 

[garrowolf]

What did you have?

 

[AnimeSniper]

I think I have a posters work from the defunct D20ModernSRD forums