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-   -   Emerging smokepowder weapons in my fantasy (http://forums.sjgames.com/showthread.php?t=63789)

fredtheobviouspseudonym 03-11-2018 02:35 PM

Re: Emerging smokepowder weapons in my fantasy
 
Quote:

Originally Posted by Icelander (Post 2055468)
Cannon round shot is actually not very effective against personnel, at least not compared to the 2-3 lbs. of smokepowder it takes to fire it and how many ca one ounce round balls might be fired from fusils for the same amount of powder.

Well . . . I've heard that the benefits of round shot include the ability to break up massed formations (i.e., pikes) at a distance. Relatively few people might be killed, but those deaths will be quite dramatic and may persuade the faint-hearted to recall an urgent engagement elsewhere. And, people ducking & dodging the rolling cannon balls will also disrupt things.

But the real prize is defense at short range -- multiple shots, langrage & canister. As Catton said of the American Civil War, a 12 pounder firing triple shotted canister would dismember charging infantry faster than their replacements could get into action.

"Well, that's the ACW." Well, a 12 pounder from 1550 could fire multiple shot rounds about as well as a Napoleon in 1862. It was in the areas of shellfire & mobility that the Napoleon shone; it was still a smoothbore firing multiple-shot rounds as in 1550. As Nathan Bedford Forrest said, "There really isn't any good way to attack a battery."

scc 03-11-2018 04:28 PM

Re: Magico-alchemical ignition
 
Quote:

Originally Posted by Icelander (Post 2164511)
One PC is receiving a set of magical pocket pistols in a 'deringer' style, made out of orichalum with double barrels 3" long. The grip of one of pistol is made from shark's tooth and the grip of the other from mother of pearl. The former pistol is decorated with engravings of the PC defeating divine emissaries of their enemies and defending his men from sharks in the ocean and the other pistol has him fighting beside sahuagin (shark men) against the nobles, priests and generals of the other side.

The weapons carry various enchantments, but the ones I'd like to get help with are the ones that ignite the smokepowder and are meant to get the most of the propellant in a short barrel.

Pulling the trigger activates an Essential Air spell to fill the barrel with the essence of oxygen and ensure rapid burning of the propellant and simultaneously causes the 3 FP version of the Ignite Fire spell to go off in the entire barrel, the equivalent of a blowtorch being applied to the 25 grains of finely-ground REF 0.8 smokepowder (about mid-way in REF between high-quality black powder and TL6 smokeless powder). A Shape Air spell ensures optimum mixing of the burning propallant and the Essential Air while the combustion is going on.

This propels a 10mm 90 grain lead and antinomy ball out the barrel. The orichalum construction means that there is no risk of catastrophic overpressure despite the near instant detonation of the smokepowder. I figure that it could use a larger powder charge, but as it's so tiny and the grip only allows three fingers, we want to avoid too much of a kick.

I can use Doug Cole's spreadsheet to find the stats, but I need to know what would be reasonable in terms of PSI, burn length and, derived from that, the muzzle velocity.

What would be a reasonable figure for muzzle velocity? 1,200 fps? 1,500 fps? 2,000 fps? 3,000 fps?

Too complicated for a start, and if I was GMing I'd say that the Ignite Fire results in the barrel heating up, dropping your rate of fire. Really what you want is Fast Fire cast on the ammo.

Icelander 03-11-2018 05:16 PM

Re: Magico-alchemical ignition
 
Quote:

Originally Posted by scc (Post 2164568)
Too complicated for a start, and if I was GMing I'd say that the Ignite Fire results in the barrel heating up, dropping your rate of fire. Really what you want is Fast Fire cast on the ammo.

Of course the barrel heats up, but it takes three times as much to heat up an orichalum barrel than a bronze one. Note that the Ignite Fire is effectively cast by the magical item in question and doesn't heat up the item itself any more than a wizard casting Ignite Fire has his fingers burnt. But obviously, the combustion of the smokepowder heats the barrel as normal.

Not that firing often enough in a minute for that to matter is likely to come up with a holdout gun like this. The PC probably can't even manage more than 8-10 shots in a minute, even with succesful Fast-Draw (Ammo) rolls and no Aiming. I can't really imagine a situation where he'd fire often enough to overheat an orichalum barrel with magical protections.

In any case, the only danger would be ammunition cook-off. The PC is immune to fire and the orichalum weapon is Fireproof, Shatterproof and Soilproof.

Fast-Fire smokepowder is a good idea, of course. Maybe not the basic load, but definately specialised ammo.


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