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Thread: Smokepowder quantities

20190904, 12:30 PM (ISO 8601)
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 Dec 2018
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Smokepowder quantities
So those of us that have looked at Gunpowder in the DMG and Smokepowder in Dragon Heist have noticed a small disconnect between how much a keg holds of one vs the other.
A few times in the Dragon Heist module, there are kegs of Smokepowder the book describes as containing 5 pounds each. The magic item at the end of the book makes no mention of the weight of a standard keg of Smokepowder, only that a keg has enough for 500 firearm shots (doses), and a packet has enough for 5.
The DMG doesn't cover shots/doses, but it does list kegs as containing 20 pounds of Gunpowder, and a powder horn holding 2 pounds. Now it since it doesn't explicitly say the powder horn or the keg have their own weights, for simplicity we'll just go with the weight being only the Gunpowder and the container as just a nonfactor.
So for the sake of getting these numbers to line up better, I'd propose that the kegs in the rooms of Dragon Heist are not 'full' kegs (they're usually in huge stacks, so if a player wants a full keg, I'd just say they decant a few kegs into one). Here's the (obvious) numbers I'm thinking of running with:
Let a 'full' keg be 20 lb. for 500 doses
Let a powder horn be 2 lb. for 50 doses
Let a packet be negligible weight for 5 doses
1 lb. of Smokepowder = 25 doses
Discharging a firearm: 1 dose
Discharging a cannon: 1 lb.
With the above numbers in mind; how many doses of Smokepowder should be used to make a stick of dynamite? The damage between the different quantities of Smokepowder and Gunpowder exploding in kegs, horns, packets, etc, has got me a bit lost of what would be a reasonably consistent number.edit: scrapped
Similarly, what would be a good volume for Smokepowder per dose (or doses)? There's bound to be a point in time where my players will want to know how much Smokepowder can be fit into a container of x*y*z dimensions.
ie: doses per cubic foot, per gallon, etcLast edited by Zhorn; 20190904 at 05:54 PM.

20190904, 01:09 PM (ISO 8601)
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20190904, 05:53 PM (ISO 8601)
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 Dec 2018
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Re: Smokepowder quantities
ok, while I was aware of real world dynamite using nitroglycerine, I was under a false impression that primitive versions of explosive sticks were make from gunpowder. Not the case, scrapping the question.
So apparently the magic ban that prevents gunpowder from exploding in the Forgotten Realms also extends to nitroglycerine (aka "halamda" to gnomes). So while dynamite might have existed at some point, it no longer does.
No dynamite existing > no point in working out a smokepowder equivalent. I'll just have to go through the numbers and have a scale from packet to keg to sort out a good explosion size:damage:doses ratio for the amounts not listed.

20190905, 01:53 AM (ISO 8601)
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Re: Smokepowder quantities
note: the following calculations are rough for simplicity just to get a basic value.
For the sake of having something to work with for tonight's game, I'm going to table rule that the kegs that the smokepowder is measured in are roughly 1 gallon in volume (~3.8 litres for us using metric for our day to day lives).
This gives a nice simple number for the volume of 500 doses worth, and seems like a volume that could be believable divided up as such, and something that could realistically be carried in an adventurer's backpack.
So with 20 lb. keg of 500 doses giving us our
1 lb. of Smokepowder = 25 doses
Applying a volume of
1 gallon = 20 lb. of Smokepowder
Rough napkin math has ~7.5 gallons per cubic foot, so
1 cubic foot = 150 lb. of Smokepowder (3750 doses)
1 gallon makes 8 pints, so
1 pint = 62.5 doses
1 pint makes 16 ounces, so
1 ounce = 3.90625 doses
Not the best solution, but it gives some working numbers for when players are using odd containers or trying to figure out how much they can carry.

20190905, 02:34 AM (ISO 8601)
 Join Date
 Mar 2011
Re: Smokepowder quantities
One can handwave this as being different keg sizes, different grain sizes and shapes (larger/bulkier grains pack less efficiently), or just that smokepowder works differently and hence requires a different quantity for firearms. (IIRC smokepowder is more volatile then nonrealms gunpowder).
Pick whatever value you think is right. Reallife black powder 'bulk density' varies a lot anyway, because of grain size and shape (like all powders).
But [url=http://www.curtrich.com/BPConversionSheet.htm[here's[/url] a conversion chart that is supposed to cover volume/weight measurements for black powder and equivalents.
(Not into guns, can't factcheck. It's just something I dug up with a quick web search.)

20190905, 10:42 AM (ISO 8601)
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 Dec 2018
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Re: Smokepowder quantities
So further with my attempts at ironing out the smokepowder rules.
Damage Dice: Not much of a change here, just setting a pattern rule to it to extend beyond the given bythebooks numbers. Triple the damage dice for the blast for every dose increase by a factor of 10.
Blast radius: Having the flat 20 foot radius seems a bit silly to me. Add more powder, bigger blast and thus bigger radius. Less powder, smaller blast, smaller radius. Proposal, start with 5 ft. blast radius for 5 doses of smokepowder, doubling the radius for every dose increase by a factor of 10. Why? The numbers line up to have a 20 ft. radius for an exploding keg, but scales downwards at a rate that would make sense to not explode a wielder of firearms and everything nearby when a shot is fired... Through a 20 ft. explosion at the point of origin when making a firearm attack would be pretty funny heh "dodge this"
Save DC: Solid DC seems odd. A bigger blast should be harder to avoid. Setting to 11+number of damage dice. As the size of the explosion increases, the number of rogues remaining unscathed approaches zero
Container Size Weight of Smokepowder Doses Damage Blast Radius Save DC Packet Negligible 5 1d6 5 ft. DC 12 Powder Horn 2 lb. 50 3d6 10 ft. DC 14 Keg 20 lb. 500 9d6 20 ft. DC 20