02-11-2014, 08:46 PM | #1 |
Join Date: Oct 2007
Location: Kentucky, USA
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GURPS Ballistics: Modifying gun damage with REF?
In my own GURPSified take on the Spelljammer D&D setting and several other kitchen sink settings, a wide variety of guns and forms of ammunition and gunpowder are available.
From serpentine to shattersand to smokepowder and more exotic variants. One thing I would like to do is figure out how substituting one explosive for another might change a gun (assume it can take the extra pressure). Now, using some algebra on the train, I've been able to determine the proportions of shot to powder, at least in the Low Tech guns. So, if I substitute a new powder with a different REF, how would I figure out the new damage of the bullet? |
02-12-2014, 06:45 AM | #2 | |||
Join Date: Nov 2006
Location: Heartland, U.S.A.
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Re: GURPS Ballistics: Modifying gun damage with REF?
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It could be argued that in typical demolition situations, the explosive force is not nearly as focused, such as it is in a gun's tube. So, you might yet justify simply using the REF as a straight multiplier.
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Last edited by Captain Joy; 02-12-2014 at 06:52 AM. Reason: There is a bit more to the story. |
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02-12-2014, 08:33 AM | #3 |
Doctor of GURPS Ballistics
Join Date: Sep 2004
Location: Lakeville, MN
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Re: GURPS Ballistics: Modifying gun damage with REF?
Most guns will be limited by their chamber pressure limit. Unless you change that, the limit on velocity won't change much.
Now, a slower burning explosive will have a big impact on velocity, due to being at max pressure longer. If you can assume redesigned guns and big pressures, I can get an answer by plugging into my spreadsheet. Give me ten minutes.
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02-12-2014, 10:18 AM | #4 |
Join Date: Feb 2005
Location: Berkeley, CA
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Re: GURPS Ballistics: Modifying gun damage with REF?
REF won't be especially useful, because it's usually normalized for destructive force, and good propellants actually aren't especially destructive.
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02-12-2014, 10:27 AM | #5 | |
Join Date: Nov 2006
Location: Fayetteville, Arkansas
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Re: GURPS Ballistics: Modifying gun damage with REF?
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02-12-2014, 10:40 AM | #6 |
Join Date: Feb 2005
Location: Berkeley, CA
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Re: GURPS Ballistics: Modifying gun damage with REF?
Not really. The point is mostly that the weight of the chamber and case is largely a function of peak pressure, while muzzle energy is a function of pressure over the entire period the bullet remains in the barrel. Given the same energy content, a fast-burning explosive and a slow-burning explosive won't produce dramatically different bullet energies, it's just that the slow-burning explosive will require a significantly lighter gun.
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02-12-2014, 01:33 PM | #7 |
Join Date: Oct 2007
Location: Kentucky, USA
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Re: GURPS Ballistics: Modifying gun damage with REF?
Assume whatever arbitrary fantasy gunpowder analog is specifically a propellant. In High Tech, the expanded explosives table has propellants that go from REF 0.3 serpentine to REF 1.2 guncotton. I think that gives plenty of wiggle room.
I'm mostly looking at TL3-4 guns, which we can assume are designed to handle whatever propellant they are given. Solid orichalcum muskets, anyone? I had just assumed pressure loss would be proportional. The same design would lose 50% of the energy as black powder or guncotton, assuming the musket is infinitely strong. And thanks for the idea of just diving by the squareroot of the old REF and multiplying by the square root of the new REF. |
02-12-2014, 02:12 PM | #8 |
Join Date: Feb 2005
Location: Berkeley, CA
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Re: GURPS Ballistics: Modifying gun damage with REF?
That will result in ahistorically large amounts of powder, since you generally just use however much powder your barrel can handle.
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02-12-2014, 02:59 PM | #9 |
Join Date: Oct 2007
Location: Kentucky, USA
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Re: GURPS Ballistics: Modifying gun damage with REF?
I think you misunderstand. What I mean is that is you substitute one propellant for another, pound for pound, without worrying about the barrel exploding from the more powerful propellant. I'm not saying I stuff the gun to capacity because it's indestructible.
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02-12-2014, 03:05 PM | #10 |
Join Date: Jun 2013
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Re: GURPS Ballistics: Modifying gun damage with REF?
That's going to require some sort of magical propellant that isn't more stressful on the weapon but otherwise functions with a higher REF - which certainly isn't out of the question for dealing with things like Essential Gunpowder or whatever. That, or virtually indestructible barrels... which would logically simply result in stuffing more powder in.
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