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kentma57
2007-12-13, 09:12 AM
While rather unusual it is not all that unlikely in the D&D world. Magic can be used to melt down and craft most metals, and you could simply bind an elemental for a power source. The question is what kind of stats should it get...

EDIT: You would probably have to have a permanent spell, or another elamental to stop it from over heating.

StickMan
2007-12-13, 10:50 AM
While rather unusual it is not all that unlikely in the D&D world. Magic can be used to melt down and craft most metals, and you could simply bind an elemental for a power source. The question is what kind of stats should it get...

EDIT: You would probably have to have a permanent spell, or another elamental to stop it from over heating.

I would have it deal 2d6-2d8 damage range 18-20/x4, 200 ft range incressment, Huge weapon so it needs a platform to work on. Might add fire damage to represent the heatedness of the thing. I'd say id cost about 5,500 GP minimum.

EldritchExMachina
2007-12-13, 10:53 AM
We're talking about a rail gun here.

Insert a ridiculous amount of damage with a x3 critical.

Nerd-o-rama
2007-12-13, 11:12 AM
I wouldn't be surprised to see someone invent this in Eberron using Air or Storm elementals, seeing as they already have a MagLev train (lol magic trainz). Regular spells probably couldn't manage it, since they deal very little with magnetism.

A pair of very large Khyber shards on either side of an armature/barrel assembly could do it. It'd have to be a siege weapon, probably one die size and let's say two dice numbers up from the heavy gunpowder bombards they have in FR, and a very long range increment. In the real world, railguns are designed for hitting things in the next country.

I can picture Lyrandar mounting one of these on a particularly huge Stormship, and calling it the Thunder Cannon. And then taking over the Lhazzar Principalities with it. Or possibly, it's Merrix d'Cannith's latest wacky supervillain scheme.

Jack Zander
2007-12-13, 11:20 AM
I would have it deal 2d6-2d8 damage range 18-20/x4, 200 ft range incressment, Huge weapon so it needs a platform to work on. Might add fire damage to represent the heatedness of the thing. I'd say id cost about 5,500 GP minimum.

What are those stats for? A handheld mini version?

Heavy catapults deal 6d6 damage. Ballistas deal 3d8. I'm going to make up a number and say 10d8 with a X4 crit. Range would be 500 ft or more. I'd make the cost based on the spells used to create the thing. Some sort of gravity spell, wall of iron for the construction and ammunition, and whatever spell lets you bind elementals (gate?).

StickMan
2007-12-13, 11:48 AM
What are those stats for? A handheld mini version?

Heavy catapults deal 6d6 damage. Ballistas deal 3d8. I'm going to make up a number and say 10d8 with a X4 crit. Range would be 500 ft or more. I'd make the cost based on the spells used to create the thing. Some sort of gravity spell, wall of iron for the construction and ammunition, and whatever spell lets you bind elementals (gate?).

Yes and you have to take more than one round to reload both of Ballistas and Catapults. This how ever this is an autofire like crazy weapon. And to be honest I would rather get hit by a Rail gun shot that a Catapult boulder. I personaly thing your dealing with an issue of scale. Its going to hurt less (Relative term) getting hit by a single shot from a rail gun that it is to have a balista bolt or bolder hit you. Getting hit by a large number of shots how ever would be devastating. The Rail gun should however have the ability to by pass armor, hardness and damage reduction anything other than adamantie should become swiss cheese I think.


Also are you basing this off real world Rail Gun or a video game/tv type thing?

3d8 damage may be appropriate but I think your over doing it by a lot if you go 10d8.

I suggest you look at what D20 modern has written up for it I'm sure they have a Rail gun in one of the books. Just for scale an M2A2 Bradley 25mm cannon does 4d12 damage and an M1A2 Abrams tank cannon, the mother of all heavy tank weapons, deals 10d12 damage a single shot from a rail gun is not going to be that close to that tank blast.

Cuddly
2007-12-13, 11:57 AM
All you need is a few million commoners....

Jack Zander
2007-12-13, 11:58 AM
I was basing it off of real world railguns and as such it was intended to be a siege weapon. Last time I checked you could only fire those once a round and they took time to reload.

You think a boulder is going to deal more damage than a large chuck of metal flying at incredible speeds? Have you ever taken a physics class?

And a railgun should deal more than any tank blast. Are you sure you know what a railgun is?

Cuddly
2007-12-13, 11:59 AM
Yes and you have to take more than one round to reload both of Ballistas and Catapults. This how ever this is an autofire like crazy weapon. And to be honest I would rather get hit by a Rail gun shot that a Catapult boulder. I personaly thing your dealing with an issue of scale. Its going to hurt less (Relative term) getting hit by a single shot from a rail gun that it is to have a balista bolt or bolder hit you. Getting hit by a large number of shots how ever would be devastating. The Rail gun should however have the ability to by pass armor, hardness and damage reduction anything other than adamantie should become swiss cheese I think.


Also are you basing this off real world Rail Gun or a video game/tv type thing?

3d8 damage may be appropriate but I think your over doing it by a lot if you go 10d8.

I suggest you look at what D20 modern has written up for it I'm sure they have a Rail gun in one of the books. Just for scale an M2A2 Bradley 25mm cannon does 4d12 damage and an M1A2 Abrams tank cannon, the mother of all heavy tank weapons, deals 10d12 damage a single shot from a rail gun is not going to be that close to that tank blast.

Actually, the hydrostatic shock from being struck by aluminum traveling at those speeds would burst your heart and make your brain hemorrhage.

Closet_Skeleton
2007-12-13, 12:01 PM
d20 future's railguns are crap (bottom of the table http://ca.geocities.com/spike_fightwicky/d20modernsrd/futurepl7.html#ranged) and pretty flavourless.

That's the only officialy stated railgun. Nobody at Wizards can be a fan of them.

Then there's always the million commoners and a quarterstaff railgun.


Yes and you have to take more than one round to reload both of Ballistas and Catapults. This how ever this is an autofire like crazy weapon.

Not really, a railgun has no reason to make it autofire. You can't even use standard automatic fire with one since it has no recoil. Autofire is pretty pointless with a railgun since nothing could survive one shot.

One shot from either a railgun or a ballista would kill you. No buts.

Blue_C.
2007-12-13, 12:01 PM
Yes and you have to take more than one round to reload both of Ballistas and Catapults. This how ever this is an autofire like crazy weapon. And to be honest I would rather get hit by a Rail gun shot that a Catapult boulder. I personaly thing your dealing with an issue of scale. Its going to hurt less (Relative term) getting hit by a single shot from a rail gun that it is to have a balista bolt or bolder hit you. Getting hit by a large number of shots how ever would be devastating. The Rail gun should however have the ability to by pass armor, hardness and damage reduction anything other than adamantie should become swiss cheese I think.


Also are you basing this off real world Rail Gun or a video game/tv type thing?

3d8 damage may be appropriate but I think your over doing it by a lot if you go 10d8.

I suggest you look at what D20 modern has written up for it I'm sure they have a Rail gun in one of the books. Just for scale an M2A2 Bradley 25mm cannon does 4d12 damage and an M1A2 Abrams tank cannon, the mother of all heavy tank weapons, deals 10d12 damage a single shot from a rail gun is not going to be that close to that tank blast.

The prototype railguns fire at rates of kilometers per second. There are issues with rail life, as the heat generated by fire any size projectile is enough to tear up the rails themselves, but they can fire. The damage of these guns is compared to that of cruise missiles, not cannon fire.

So, given magic's ability to work around the laws of physics, I think artificed railgun is going to beat a tank blast.

Edit: @Closet Skeleton. I think those rail guns are handheld versions, like a coilgun.

Jack Zander
2007-12-13, 12:04 PM
Actually, the hydrostatic shock from being struck by aluminum traveling at those speeds would burst your heart and make your brain hemorrhage.

That and even if it misses a person (who the hell would fire a railgun at a person anyway?) if the projectile is close enough to the target the wind blast will rip their flesh and knock them over anyway.

Closet_Skeleton
2007-12-13, 12:10 PM
Apparently I was slightly wrong about that being the only railgun as these two mecha weapons exist:

M-300 RHINO MASS CANNON (PL 7)

LT-5 LONGSHOT MASS DRIVER (PL 8)

Niether are electromagnetic, the first one works in the same retard techobabble way as the official "railgun" and the second is just a nondescript mass driver. You can find stats here (http://ca.geocities.com/spike_fightwicky/d20modernsrd/futuremecheq2.html) but they're not that useful.

Jack Zander
2007-12-13, 12:14 PM
All you need is a few million commoners....

True, but that railgun only deals 1d6 damage.

StickMan
2007-12-13, 12:14 PM
I was basing it off of real world railguns and as such it was intended to be a siege weapon. Last time I checked you could only fire those once a round and they took time to reload.

You think a boulder is going to deal more damage than a large chuck of metal flying at incredible speeds? Have you ever taken a physics class?

And a railgun should deal more than any tank blast. Are you sure you know what a railgun is?


OK yes a rail gun is going to have a incredibly great deal more physical force that a catapult your totally right there. How ever that is not the same as damage. I get hit by a Rail Gun odds are I'm dead yes and there is a large hole in me some were, I get hit by a Catapult odd are I'm dead and flat as a pancake. That for me is the difference in damage. However like I said the Rail gun should by pass a lot/all hardness, armor, and damage reduction which a catapult does not do, also I should keep going and kill more stuff behind me. Also I'm basing this off of more recently in testing fast firing Railguns but many up till now have only been slow fire so you are correct.


Now if we really want to talk up to date, still in testing, Railgun tec, lets talk about the Rail gun that converts its ammo to plasma the US military has been working on. That I'd say deals as much damage as you want cause well its plasma, kinda breaks the game however:smallbiggrin: .

Cuddly
2007-12-13, 12:14 PM
Can you imagine that in game though?

"Something streaks at you- all you hear is a thumping noise as the air splits with such force that it lacerates your flesh. (everyone here takes 4 damage). You turn back to see Hrothgar collapse, a hole through his chest the size of your fist. His eyes and ears bleed."


"What trickery is this, magician!?"

Nerd-o-rama
2007-12-13, 12:15 PM
Apparently I was slightly wrong about that being the only railgun as these two mecha weapons exist:

M-300 RHINO MASS CANNON (PL 7)

LT-5 LONGSHOT MASS DRIVER (PL 8)

Niether are electromagnetic, the first one works in the same retard techobabble way as the official "railgun" and the second is just a nondescript mass driver. You can find stats here (http://ca.geocities.com/spike_fightwicky/d20modernsrd/futuremecheq2.html) but they're not that useful.
There's starship weapons too, but yeah they all suck. Actually, compared to starship HP, all of their weapons are pretty damn ineffectual, except for a few of the mines. But I digress.

Hm. Perhaps a railgun should deal physical damage in a (very long) line, reflex for none, rather than being an attack roll? With the ability to go through objects it destroys, like a Lightning Bolt spell. I mean, it'll cut through pretty much anything pre-modern like it was cheese.

V Edit ninja'd

Jack Zander
2007-12-13, 12:17 PM
Can you imagine that in game though?

"Something streaks at you- all you hear is a thumping noise as the air splits with such force that it lacerates your flesh. (everyone here takes 4 damage). You turn back to see Hrothgar collapse, a hole through his chest the size of your fist. His eyes and ears bleed."


"What trickery is this, magician!?"

Freakin' awesome.

And yes Stickman, railguns should deal area damage in a line similar to lightning bolt. But I disagree that railguns should bypass DR and harness. Only energy weapons should have that ability. A railgun (not these newfangled plasma cannons) are still just a really big chunk of metal and the reason they bypass DR and harness is simply from the massive amount of damage they deal, not any special ability. If a material was hard/thick enough, it could stop a railgun projectile. I dunno if we have any material like that in the real world though.

Xefas
2007-12-13, 12:23 PM
"Something streaks at you- all you hear is a thumping noise as the air splits with such force that it lacerates your flesh. (everyone here takes 4 damage). You turn back to see Hrothgar collapse, a hole through his chest the size of your fist. His eyes and ears bleed."

"What trickery is this, magician!?"

The only people who would say that are those with wisdom as a dump stat.

Everyone else is already running away.

Closet_Skeleton
2007-12-13, 12:54 PM
There's starship weapons too, but yeah they all suck. Actually, compared to starship HP, all of their weapons are pretty damn ineffectual, except for a few of the mines. But I digress.

The Starship gargantuan railgun deals 6d12. d20 Future criticises tehm for having no explosive charge yet the scientific article I read said that once you get to the level of energy transferal you get in a useful railgun explosives don't increase the damage at all (partly because they would be atomised but even then it's a waste).


I get hit by a Rail Gun odds are I'm dead yes and there is a large hole in me some were, I get hit by a Catapult odd are I'm dead and flat as a pancake. That for me is the difference in damage.

No. You just don't get it.

You get hit by a railgun, you do not get a hole in you. Your body is atomised.

The force of the collapsing Twin Towers (to use a not so palatable example) was enough to blast concrete into dust.

Arrows put holes in you. A bullet (from a firearm or a railgun) is not comparable to an arrow. An arrow has a sharpened head. A bullet is effectively blunt. You can stab yourself with an arrow, a bullet outside a gun is safe to sell on keychains. What does damage with bullets is pure transferal of force. Guns are infact energy weapons, the bullet just transfers the energy. When you get hit by a high callibre bullet, the bullet itself is just a malformed bit of lead that by itself is would hurt less than an elastic band. However the energy transferal liquifies your insides.

When you launch a projectile from a railgun, that projectile contains the energy you put into the railgun (minus any you wasted from inefficiency). You cannot compare being hit by a railgun slug to being hit by a stone since that slug can easily have the same energy as a lightning bolt. Being hit by such a weapon is more like being hit by a lightning bolt.

StickMan
2007-12-13, 01:21 PM
Honestly I'm just trying to make things work in DND terms. I mean if we want to be realistic basically any thing a Rail Gun hits in the DND universe should just die. Maybe the largest of Red Dragons would not, can't be sure here but, for the most part you hit something with a real world railgun its gone I know. You don't need to explain how a Railgun works I basic physics, but like I said real world does not translate to fantasy world.

Jack Zander
2007-12-13, 01:56 PM
Honestly I'm just trying to make things work in DND terms. I mean if we want to be realistic basically any thing a Rail Gun hits in the DND universe should just die. Maybe the largest of Red Dragons would not, can't be sure here but, for the most part you hit something with a real world railgun its gone I know. You don't need to explain how a Railgun works I basic physics, but like I said real world does not translate to fantasy world.

Sounds like you need to get a new fantasy world mechanics, or learn how DnD mechanics mirror the real world then.

StickMan
2007-12-13, 02:20 PM
Sounds like you need to get a new fantasy world mechanics, or learn how DnD mechanics mirror the real world then.

Um not at all? My favorite example just look at archery in the game, its the most unrealistic thing every. Mechanics and real life don't add up in DND every. Most things are abstract at best (Example the HP system). How about the Commoner Rail Gun yea thats how the real world works.

Jack Zander
2007-12-13, 02:32 PM
Um not at all? My favorite example just look at archery in the game, its the most unrealistic thing every. Mechanics and real life don't add up in DND every. Most things are abstract at best (Example the HP system). How about the Commoner Rail Gun yea thats how the real world works.

Glitches are true of any system. As for the archery thing, only past level 6 can you fire 3 shots in under 6 seconds, and that's getting into superhero physics then.

HP is not abstract. (http://tvtropes.org/pmwiki/pmwiki.php/Main/OnlyAFleshWound)
Relative HP may be though. For example, an attack that does 5 damage to a level 1 fighter is a nice wound, but to a level 5 fighter tis merely a scratch as he was able to roll with the blow. If you actually break the system down (not taking into account glitches) you'll find it does a damn good job of realism for most things. And damage happens to be one of those them.

StickMan
2007-12-13, 02:49 PM
Glitches are true of any system. As for the archery thing, only past level 6 can you fire 3 shots in under 6 seconds, and that's getting into superhero physics then.


Being able to fire more than once in a round is insane a good archer in the real world would have a hard time firing more than one in 6 seconds with any degree of accuracy. Also look at the Range on a long bow, if you have ever in your life fired a bow you know that your not accurate out to 100ft. You sure as heck don't have any chance to hit at 300ft, in DND you have a good chance, if I take 20 shots at some thing 1000ft away from me I'm not going to hit it unless its a barn.


Relative HP may be though. For example, an attack that does 5 damage to a level 1 fighter is a nice wound, but to a level 5 fighter tis merely a scratch as he was able to roll with the blow. If you actually break the system down (not taking into account glitches) you'll find it does a damn good job of realism for most things. And damage happens to be one of those them.
How is that not abstract? That seems like the definition of an abstract system to me


Science and DND don't ever mix, yes some times the guys at wizards do something right but over all its just a game it does not have to be realistic and its not. We can talk about physics, Biology, what ever and I can give you examples of how unreal DND is but that is to be expected when your wizard character is telling the laws of physics to sit down and shut up.

MagFlare
2007-12-13, 02:57 PM
I thought the D&D equivalent of a railgun was a line of 1st level commoners, each of which has prepared a (free!) action to pass a spear from the person behind him to the person in front of him. The distance the spear travels in one round is limited only by the number of people in the line - and while I'm no physicist and therefore unable to comment authoritatively on things like friction coefficients, it occurs to me that the person at the end of the line should probably be wearing some sort of gloves.

Jack Zander
2007-12-13, 02:57 PM
I guess most people do not take rapid shot as their first level feat then. Makes sense to me. If you aren't skilled (read proficient) with a bow you don't have a good chance of hitting things farther away. Also, most bows people use today are shortbows. Longbows are massive.

If 'having more HP means being able to roll with blows better' is abstract to you, what's your definition of concrete? It's like having a higher BAB means you are more accurate.

Jack Zander
2007-12-13, 02:58 PM
I thought the D&D equivalent of a railgun was a line of 1st level commoners, each of which has prepared a (free!) action to pass a spear from the person behind him to the person in front of him. The distance the spear travels in one round is limited only by the number of people in the line - and while I'm no physicist and therefore unable to comment authoritatively on things like friction coefficients, it occurs to me that the person at the end of the line should probably be wearing some sort of gloves.

I think cuddly covered that for you already.

Jayabalard
2007-12-13, 03:04 PM
A Glitter Boy's Boom gun deals 4d6 MDC; that sounds about right to me.

Zeal
2007-12-14, 12:51 AM
Can you imagine that in game though?

"Something streaks at you- all you hear is a thumping noise as the air splits with such force that it lacerates your flesh. (everyone here takes 4 damage). You turn back to see Hrothgar collapse, a hole through his chest the size of your fist. His eyes and ears bleed."


"What trickery is this, magician!?"

But really, who would be shooting Beowulf with a railgun anyways?

Yami
2007-12-14, 02:04 AM
I just want to thank the OP for actually not talking about the line o' commoner goodness.

reorith
2007-12-14, 02:34 AM
snip(who the hell would fire a railgun at a person anyway?) snip

i would given the opportunity.

Magnor Criol
2007-12-14, 02:37 AM
But really, who would be shooting Beowulf with a railgun anyways?

A time traveler who didn't like the movie.



As far as the railgun - I think we're trying to limit the wrong factor here. Railguns were meant to obliterate things, be they objects or any people unlucky enough to be in their path. Damage should be exceedingly high, and I don't think a high crit range - or even some sort of bonus to confirm crits - is out of the question. Things that get hit by a railgun are going to die, or at least be severely crippled.

The limiting factors should be in other areas, not damage.

Expense - They should be expensive to develop, expensive to build, and expensive to maintain. They'd need lots of special materials, and the projectiles would need to be something strong enough to withstand the forces involved in launching it. It'd probably take a good deal of mages to keep it running (depending on how you say it works.)

Aiming - They're not small or easy to handle. They're large, bulky things that require their own special mounting system and base. So they should get some horrendous penalties to attack. Part of this may be covered by the 'siege weapon' status they'd have; I'm not too familiar with siege weapon rules. But it should take almost a natural 20 to hit a character who's not immobilized with a railgun.

Power Level - A nation (or organization, or character) that can build and field railguns is a huge threat to other nations (or etc.) that can't. Anything that shows itself to have that sort of power will likely find itself at the pointy end of an alliance of its enemies, all banding together to take out the suddenly much more powerful threat. Alternately, they'd find themselves subject to lots of nations / organizations / characters who want that power and tech for themselves, and come seeking to wrest the railgun away by force.

Closet_Skeleton
2007-12-14, 05:47 AM
But really, who would be shooting Beowulf with a railgun anyways?

Mecha-Grendel?

Eco-Mono
2007-12-14, 06:29 AM
Rail gun
This fearsome magical siege weapon was designed during a war between two magocracies, when one of the sides found itself attacking a city with walls of iron and antimagic fields in place. Using a combination of electrical evocations and telekinetic spells, it accelerates a large piece of metal to terrific speeds, tearing a swath of destruction in its wake. Of course, the ammunition must be carefully chosen, such that it does not simply disintegrate under the stresses created by the device.

Use: Activating it is a standard action. After firing, requires 1d4+1 rounds to recharge, and requires a full-round action spent to reload it.
Damage: 22d6, plus fortitude save DC 22 or be destroyed anyway. Dealt to each object in the shot's path (not just in the same square, though!), until maximum range has been reached or until something survives the damage dealt.
Cost: 60,000gp

Ammo options:
Iron - will travel 250ft before burning up. 1000gp
Iron/adamantine alloy - will travel 1000ft before burning up. 5000gp
Pure adamantine - would be nice, but you can't afford it.

To create: CL 15, chain lightning, telekinesis, reverse gravity, the usual cash and experience.

Balanced on disintegrate, with some tweaks.

kentma57
2007-12-14, 07:25 AM
But that does not truely represent the mass fire quality of a rail gun...

Yes I did start the thread...

Closet_Skeleton
2007-12-14, 09:03 AM
But that does not truely represent the mass fire quality of a rail gun...

A rail gun has no mass fire property (unless you mean that it fires mass, which it doesn't because there's no fire involved).

If you want a magic gatling gun don't ask for a magic rail gun.

Triaxx
2007-12-14, 09:35 AM
Being able to fire more than once in a round is insane a good archer in the real world would have a hard time firing more than one in 6 seconds with any degree of accuracy. Also look at the Range on a long bow, if you have ever in your life fired a bow you know that your not accurate out to 100ft. You sure as heck don't have any chance to hit at 300ft, in DND you have a good chance, if I take 20 shots at some thing 1000ft away from me I'm not going to hit it unless its a barn.

I'd just like to point out that this is complete bull. 300ft? That's only a 100yrds. That's not nearly an impossible shot. The effective range of a bow is about 70yrds. I've witnessed kill shots at that range, so I know for a fact it's possible.

As for hitting a barn at 1000ft? Possible, but only with a height advantage and or an extremely powerful bow. Either an english Longbow, or a very powerful compound.

Baxbart
2007-12-14, 10:32 AM
We really need to define better what is meant by 'rail gun'. Technically speaking, it can be contructed on a range of scales (especially with D&D allowing us the good graces of magic to get around those pesky laws of physics).

Hell... if it were a real hand-held (or tripod mounted) railgun, then maybe it'd do the damage put forth by Eco-Mono.

For a siege scale weapon (one that would be better off mounted on an orbital space station for taking out starships with one shot, or fired into neighbouring countries), its fairly pointless trying to put numbers to the thing. With the benefits of magic duplicating the magnetic acceleration effect (without the problems of heat melting the rails themselves) - this thing would pretty much destroy everything it got near... and when it actually impacted on something with significant mass to stop it (say... the earth, for example), the transferral of kinetic energy would give some hideously large propagating blast wave something akin to a minor thermonuclear detonation.

Largest red dragons possibly surviving being hit? HA! Not a bloody chance - This thing is ultimate overkill, designed to take out cities and reinforced installations with one shot.

Hell, you don't NEED multiple shots per round. Even if you spent a month aiming the damn thing, you could do it from the safety of your own home (with magic divinations replacing GPS guidance and targeting), push the button and watch that pesky dark and evil enemy citadel vanish in a mushroom cloud of dust and debris (along with the treasure :smalleek: )

(I don't like d20 Modern, but I justify this by drawing comparison to GURPS - which actually has a minutely detailed weapon design system. A Rail Cannon, some 40-50 metres in length, would lob a projectile hundreds, even thousands of miles, and still have enough energy left over to waste a city - tis just a shame about the collapsing rails due to heat)

Cuddly
2007-12-14, 02:10 PM
Rail gun
This fearsome magical siege weapon was designed during a war between two magocracies, when one of the sides found itself attacking a city with walls of iron and antimagic fields in place. Using a combination of electrical evocations and telekinetic spells, it accelerates a large piece of metal to terrific speeds, tearing a swath of destruction in its wake. Of course, the ammunition must be carefully chosen, such that it does not simply disintegrate under the stresses created by the device.

Use: Activating it is a standard action. After firing, requires 1d4+1 rounds to recharge, and requires a full-round action spent to reload it.
Damage: 22d6, plus fortitude save DC 22 or be destroyed anyway. Dealt to each object in the shot's path (not just in the same square, though!), until maximum range has been reached or until something survives the damage dealt.
Cost: 60,000gp

Ammo options:
Iron - will travel 250ft before burning up. 1000gp
Iron/adamantine alloy - will travel 1000ft before burning up. 5000gp
Pure adamantine - would be nice, but you can't afford it.

To create: CL 15, chain lightning, telekinesis, reverse gravity, the usual cash and experience.

Balanced on disintegrate, with some tweaks.

Make it affect objects, so undead aren't immune to the fort save. And so it obliterates objects.

Wardog
2007-12-14, 05:59 PM
Are you sure you're not overestimating the power of a railgun?

I remember watching a documentary some years ago about the old SDI ("Star Wars") project, where they discussed railguns (among other things).

If I remember right, the prototypes that had been built and tested were firing small projectiles (maybe a bit larger than a large bullet, but less than an inch diameter), made of nothing more exotic than plastic (coated in metal so they were magnetic).

These were fired at speeds of around 10km per second, and could punch large holes (several inches across) in steel plates (probably about an inch thick). (They designers wanted to get the speed up to around 25km/s, but the guns couldn't withstand the forces involved).

I don't know what the rate of fire was, but I'm pretty sure they were very high - quite unlike most railguns seen in fiction/games. Remember: they were designed to shoot down nuclear missiles in flight (one of the main reasons for having high RoF guns is not to do more damage, but to increase the chance of actually hitting the target).


Now, I can imagine that you could also have a "siege weapon" railgun, that fired heavier projectiles at a slower rate, causing more damage overall; however I seriously doubt you would be getting nuclear bomb-equivilent damage.


As for "could anything survive a hit from a railgun?" - while I'm sure you could one-shot dragons and all sorts of other massively tough creatures with a railgun, that would require hitting them in the right place. A hit to the arm or leg would probably take the limb clean off, but it wouldn't kill the creature. (Unless losing a limb by any other means would also kill it).



Oh, and as for:

That and even if it misses a person (who the hell would fire a railgun at a person anyway?) if the projectile is close enough to the target the wind blast will rip their flesh and knock them over anyway.
Nah - you're thinking of a .50BMG rifle/machinegun.

.50BMG - the Chuck Norris of the firearm world ;)




Edited to add:
Also, there's really no point in making a hand-held rifle. The limiting factor on the power of a handheld firearm isn't how fast you can propel the bullet, its how much recoil the user can control. You could build a handgun that fired 20mm rounds, but no-one could use it effectively.

Of course, we're talking about a fantasy scenario, and you could just declare that the rail rifle has had a permanent Vograth's Recoil Damping spell placed on it. But then you might as well just give your soldier a +5 Crossbow of Piercing.

A magically-powered siege railgun on the other hand would at least be an interesting and different enough item to give a unique flavour (and interesting tactical options) to a technomagic army/society.

Closet_Skeleton
2007-12-14, 06:22 PM
Are you sure you're not overestimating the power of a railgun?

A railgun can be a couple of magnets attatched to a ruler and be harmless, but a railgun is only useful if it's huge. A railgun's power is directly proportional to its length, so you get all flavours of power with railguns. You can make a short railgun, but its damage won't be worth while compared to other weapons of its size. It's only huge railguns that actually have a point to them.

An actually useful railgun would have to be the equivilant of a battleship's cannon. On any smaller scale a railgun is weaker than other kinds of gun.


Remember: they were designed to shoot down nuclear missiles in flight

That's what everything in "Star Wars" was designed to do. It's not really a role that Railguns are that good at, apart from them being fast. In D&D, there are no nuclear missiles so it isn't important. Flying dragons would be a good target for railguns but they're a lot slower than missiles.


Now, I can imagine that you could also have a "siege weapon" railgun, that fired heavier projectiles at a slower rate, causing more damage overall

Projectile weight isn't a factor in railguns, since the weight of the projectile isn't the source of the damage. Weight isn't really the most efficient manner of dealing damage with weapons, hence the shockput's lack of popularity despite it's lethalness.


however I seriously doubt you would be getting nuclear bomb-equivilent damage.

We're talking about howister scale damage.


Oh, and as for:
Nah - you're thinking of a .50BMG rifle/machinegun.

.50BMG - the Chuck Norris of the firearm world ;)

A useful railgun is more powerful than a machine gun, so it would be even worse. The more correct comparison is an artillery shell, just without the shrapnel.


Of course, we're talking about a fantasy scenario, and you could just declare that the rail rifle has had a permanent Vograth's Recoil Damping spell placed on it. But then you might as well just give your soldier a +5 Crossbow of Piercing.

I've thought of using recoil dampening spells on blunderbusses before. Though a railgun has no recoil. A gun has recoil because exploding powder goes in all directions, a railgun does not use stored energy (in chemicals or elastic materials) and only projects force in a single direction. A heat sink spell would be more useful. The problem with handheld railguns is not that they have recoil but that they're pea shooters.

A magic railgun in a D&D world would be a siege weapon for knocking down castle walls from a mile away, a ground to air emplacement weapon for taking out dragons or a weapon for picking off large creatures like giant's or dire mammoth's in whatever bizare fantasy army you're fighting.

Baxbart
2007-12-14, 06:24 PM
Again, the bore comes up.

I am talking about siege scale weaponry, and as such I'm expecting it to fire appropriate ammunition. Yes, rail guns on that scale are fairly impractical given current technological standards.

BUT,

This is D&D we're talking about here, and its magic. We're assuming there are spells to counter the effects (if any, since its magnetic acceleration) of recoil, as well as pretty much negating the internal stresses put on both projectile and coil (rails).

Depends on the trajectory now, really. It would deal some arbitrarily large amount of damage - and fair enough, would probably not kill a dragon if it only took off a wing. But I'm also referring to its use in lobbing projectiles across nations... so the ballistic arc will mean the shell is coming down from above. If it hits the dragon, or lands next to it, is a moot point - assuming we have the magical means of stopping the projectile from disintegrating at high speeds, that kind of kinetic energy is going to blow the everloving hell out of anything nearby.

I know its vaguely metascience and there is magic involved, but its not all that hard to work out equivalent kinetic energy of, say, a 200-300 lb reinforced shell, dropping out of the lower stratosphere at... lets say around 10km/s after generously allowing for friction losses. That is one hell of a lot of energy.

I'd also be partial to jumping aboard the bandwagon that says a projectile passing you at 10-25km/s will do some damage to an unprotected, squishy commoner.

Cuddly
2007-12-14, 06:31 PM
Now, I can imagine that you could also have a "siege weapon" railgun, that fired heavier projectiles at a slower rate, causing more damage overall; however I seriously doubt you would be getting nuclear bomb-equivilent damage.

No one is suggesting they would to that level of damage. However, the amount of energy in an object traveling 25km/h would be enough to put big holes in lots of stuff.


As for "could anything survive a hit from a railgun?" - while I'm sure you could one-shot dragons and all sorts of other massively tough creatures with a railgun, that would require hitting them in the right place. A hit to the arm or leg would probably take the limb clean off, but it wouldn't kill the creature. (Unless losing a limb by any other means would also kill it).

You know getting shot in the leg with a large caliber gun can kill you due to hydrostatic shock? All the blood in your body gets pushed the wrong way and puts a ton of pressure on all the wrong stuff. Such as your brain, or heart.




Also, there's really no point in making a hand-held rifle. The limiting factor on the power of a handheld firearm isn't how fast you can propel the bullet, its how much recoil the user can control. You could build a handgun that fired 20mm rounds, but no-one could use it effectively.

I'm not sure you'd have recoil, since you're using magnets.



Projectile weight isn't a factor in railguns, since the weight of the projectile isn't the source of the damage. Weight isn't really the most efficient manner of dealing damage with weapons, hence the shockput's lack of popularity despite it's lethalness.

Well, it's a factor of mass AND weight. We like to call it momentum. When shotputs could be properly hurled, ie, by gunpowder in a canon, they became very popular.

FlyMolo
2007-12-14, 06:33 PM
Right, having read a bit of the literature, and assessed the truly enormous pile of dead catgirls, this is my 2p.

Railguns are silly. Even the real-world equivalents are silly. This thing fires a projectile at one half escape velocity. Some fire at more than escape velocity.(Just point it straight up and boom! Instant satellite)

And for those of you insisting that a DnD railgun should have high rates of fire(more bullets in less time), I feel I should remind you that current railguns need to be rebuilt after every shot. Because they melt and come apart a bit at the seams each time they're fired. There's more justification for building a DnD trebuchet or something with high rates of fire. That would be simpler. Just persuade a balor or something strong to pushing the weight up high real quick.

Also, someone said that railguns have no recoil. Not so. They don't slide backwards after firing, but that's not the same as no recoil. The recoil is the thing responsible for wrecking the gun after every shot. These things produce ridiculous amounts of heat and fall apart all the time.

Edit: And there's no point to a handheld version. It would consume a huge amount of energy, and have MORE recoil than a standard gun(assuming greater muzzle velocity. And if you're not going to have that, just get a gun. a regular one. They're cheaper and don't explode.)

And If you're going to produce crazy RL weapons in DnD, just build a cannon. Then install a quickening spell on the top, and watch as you fire projectiles at 3x the speed! Hey presto!


Edit 2: Gah can't stop myself. A railgun simply makes a bit of metal fly very very quickly. IT would quite probably kill you if it hit you. However, it would have a seriously limited range. You couldn't fire this thing into an adjacent country because it would simply enter orbit. And possibly hit the moon. (The damn moon, people!) If it hit near you, it would make a really deep hole in whatever it was it hit. Yes, yes, sonic boom's concussive shock, etc etc. The projectile weighs less than 10 pounds, yes? So the crater wouldn't be very wide. Call it the size of your backyard, and just getting deeper with increased speed. Although, without resorting to space travel, there's no way to point it down.

Edit 3: V Yes you would feel the recoil. If the muzzle speed is substantially higher than a standard guns, you would feel the recoil so hard it would break your hand. And that's just the laws of physics. Short of a tougher hand, your out of luck. no way around that.

Cuddly
2007-12-14, 06:49 PM
Oh yeah, I was thinking of a gauss gun.

But would you feel the recoil if you could somehow hold the gun?


I imagine Tubeof Force would keep that friction down to a minimum :smallcool:

kentma57
2007-12-14, 06:56 PM
Again, the bore comes up.

I am talking about siege scale weaponry, and as such I'm expecting it to fire appropriate ammunition. Yes, rail guns on that scale are fairly impractical given current technological standards.

BUT,

This is D&D we're talking about here, and its magic. We're assuming there are spells to counter the effects (if any, since its magnetic acceleration) of recoil, as well as pretty much negating the internal stresses put on both projectile and coil (rails).

Depends on the trajectory now, really. It would deal some arbitrarily large amount of damage - and fair enough, would probably not kill a dragon if it only took off a wing. But I'm also referring to its use in lobbing projectiles across nations... so the ballistic arc will mean the shell is coming down from above. If it hits the dragon, or lands next to it, is a moot point - assuming we have the magical means of stopping the projectile from disintegrating at high speeds, that kind of kinetic energy is going to blow the everloving hell out of anything nearby.

I know its vaguely metascience and there is magic involved, but its not all that hard to work out equivalent kinetic energy of, say, a 200-300 lb reinforced shell, dropping out of the lower stratosphere at... lets say around 10km/s after generously allowing for friction losses. That is one hell of a lot of energy.

I'd also be partial to jumping aboard the bandwagon that says a projectile passing you at 10-25km/s will do some damage to an unprotected, squishy commoner.

Thank you, this is the kind of thinking I was hoping for. With magic we can counter any negative effects involved with a rail gun; size, rade of fire, progectile speed, no problem, use scrying magic to aim and well you get the idea...

The real question is what magic should be used, what should its stats be and how much shouls it cost?

Demented
2007-12-14, 06:58 PM
I'm not sure you'd have recoil, since you're using magnets.

Example: Hold a magnet against another magnet. Your hand can feel the repulsion or attraction between the two magnets.
Conclusion: There's nothing special about electromagnetism that would make recoil nonexistant.


For that matter, I don't see what's so special about a railgun. You don't necessarily have to make one that shoots stuff real fast. And I don't recall D&D ever using magnets for anything. So I'd have to assume the emphasis is on a railgun that accelerates things to near-light-speed. Since D&D doesn't use physics, however, I'm unsure what light-speed would be.
So this is just one utterly confusing thread.

Triaxx
2007-12-14, 07:07 PM
I can level a city with my staff. Why would I build a Rail Gun, rather than a Coil Gun? (Of course this begs the question, why would I build it to begin with?)

Electro-magnetic conduction works well, and I can discharge a bolt of lightning to generate the electro-magnetic field.

Cuddly
2007-12-14, 07:09 PM
Example: Hold a magnet against another magnet. Your hand can feel the repulsion or attraction between the two magnets.
Conclusion: There's nothing special about electromagnetism that would make recoil nonexistant.

Wow, terrible analogy.
The recoil of a rifle is from the small explosion inside pushing on the gun as it pushes the bullet out. You know, equal and opposite reactions and all that.

In the case of a railgun, all the force is angular, so I was wondering if it'd all cancel each other out for the guy holding the gun.


For that matter, I don't see what's so special about a railgun. You don't necessarily have to make one that shoots stuff real fast. And I don't recall D&D ever using magnets for anything. So I'd have to assume the emphasis is on a railgun that accelerates things to near-light-speed. Since D&D doesn't use physics, however, I'm unsure what light-speed would be.
So this is just one utterly confusing thread.

Oh, you know, accelerating small objects fast enough to knock down walls or punch holes in tanks. Being able to hit stuff in orbit. You know, stuff like that.

FlyMolo
2007-12-14, 07:57 PM
In the case of a railgun, all the force is angular, so I was wondering if it'd all cancel each other out for the guy holding the gun.



No. It wouldn't. Ever. Newton's 3rd law says, roughly. "I fling something very hard that way. It pushes me back with the same force, in the opposite direction".

So If the gun pushes on the projectile, the projectile pushes back. And the gun pushes on you. Quite hard. If all the forces are going to cancel each other out, nothing is going to fling your bullet.

It has nothing to do with gases pushing on some the parts of a gun. It's an incontrovertible natural law. There's nothing you can do to get around it.

Sorry if I'm a little annoyed. I'm tired of people making the same mistake.

magic8BALL
2007-12-14, 08:02 PM
Wow, terrible analogy.
The recoil of a rifle is from the small explosion inside pushing on the gun as it pushes the bullet out.

Actually, thats a fantastic analogy. Force provided my the magnet pushes the object in one direction, the magnet in the other.


You know, equal and opposite reactions and all that.


Ooh! Beaten to the mark!

Demented
2007-12-14, 08:43 PM
Well, it seems I was beaten to the punch.
But, if you still want a long reply, my post is in the spoiler. =D


In the case of a railgun, all the force is angular, so I was wondering if it'd all cancel each other out for the guy holding the gun.
Not for the guy holding the gun. The force between the two rails is angular, but the effect on the bullet is linear. That "equal and opposite reaction" still applies, meaning your railgun is going to have a linear force push back on it, a la magnets. Hence, recoil.

It's a very appropriate analogy. (I didn't mention rifles either.)

If you want to fire really fast projectiles with your hand-held railgun, you want to shoot really tiny bullets, or get yourself some powered armor.

For what it's worth, anti-tank weapons can already punch holes in walls and other tanks. "Recoilless" weapons (really just rockets in tubes) can probably do it in a shoulder-mounted fashion. Though, you do get your face filled with rocket exhaust.
Also, check out the Paris Gun (http://en.wikipedia.org/wiki/Paris_gun).


Anyway... The original post was a bit vague, which is probably why there's so much discussion little consensus. Though, if I were to pick it apart, I'd assume he wants someone to make a railgun out of DnD resources, then stat out the results. Which is impossible, since DnD doesn't have magnetism, or even a way to accelerate an already-moving object.
Though, you could always try the Far Shot feat instead. :smallamused:

kentma57
2007-12-14, 09:52 PM
Anyway... The original post was a bit vague, which is probably why there's so much discussion little consensus. Though, if I were to pick it apart, I'd assume he wants someone to make a railgun out of DnD resources, then stat out the results. Which is impossible, since DnD doesn't have magnetism, or even a way to accelerate an already-moving object.

Well let us assume that a rail gun is feasible, could we atempt to make a consensus on construction and damage...

magic8BALL
2007-12-14, 09:59 PM
Get the stats for a ballista, and call it a rail gun.

Probably buff it up a bit if you're looking for more 'realism', I think a ballista is only 3d8 or something. But realism isn't D&D strong point anyway.

Why would you want a railgun anyway? If you're going to use powerful magic, why not cast a high level spell? Desintegrate's only level 5... 6..? I Forget. Imagine a 9th level equivilent, then have a look at any rail gun.

Demented
2007-12-14, 10:55 PM
Here's a quick and simple weapon enchantment...

Railgun:
Magical effect that alters the nature of a bow, increasing its damage by two size categories, range increment by 100', and allows it to use any appropriate metal object as if it were an arrow with no penalties. Only ranged weapons that do not recieve a damage benefit from ability bonuses may be railguns.
Strong evocation; CL 16th; Craft Magic Arms and Armor, forceful hand; Price +3 bonus.

StickMan
2007-12-14, 11:08 PM
I'd just like to point out that this is complete bull. 300ft? That's only a 100yrds. That's not nearly an impossible shot. The effective range of a bow is about 70yrds. I've witnessed kill shots at that range, so I know for a fact it's possible.

As for hitting a barn at 1000ft? Possible, but only with a height advantage and or an extremely powerful bow. Either an english Longbow, or a very powerful compound.

OK as much as I really did not want to post on this tread again:
I admit it was a bit of an over statement but you lose a lot of accuracy after 100 feet but in DND world its only a -2 and I would like to point out that in the real world your not in a combat situation most of the time (I would hope). Odds are you've been hunting, I shoot just for fun my self. I'm an ok shot but I take time to line up a longer shot and if I was expected to shoot once every 6 seconds at someone over 100 ft away from me yea I don't think I'll hit often. I have uncles that bow hunt quite a bit and if the target is at a range past as you said 70 yrds the will not take the shot. But when they do they are taking a shoot comely taking in to account all the little things at that range. Combat you don't have time for that.

In DND however we are expected to believe that your first level characters are lining up and making 100 ft shots in combat fire off 1-2 arrows every 6 seconds. I think my point stand.

Jack Zander
2007-12-15, 12:41 AM
To someone who is trained in bowmanship (if that's a word) it's not. I'm sorry dude, but I doubt you or your uncles are trained soldiers with the longbow, or have even seen a longbow before. Therefore you are taking a -4 to attack with a shortbow which has a much shorter range.

If you give me something as simple as a pistol, I'm going to have to aim and be careful with it if I want to actually hit something. If you give either of my two brothers the same pistol who are soldiers trained in firearms usage, they can probably line up a shot in a split second.

Granted bows take longer to fire from the drawback, but the actual aiming only needs about 1 second or less for a skilled bowman (read: not your uncles).

Triaxx
2007-12-15, 07:32 AM
Archery is the word you wanted.

As for combat accuracy beyond 30yards, that's why english longbowmen always used volleys of arrows. On the other hand, Apache indians were master archers even with their shortbows. As for a combat archer, if you're engaging over 30ft, you do have time to aim. Even a level 1 character is only going to get off one shot, and likely miss. A level five elven ranger is going to take one shot, and likely hit. Why? Proficiency with the weapon.

Under 30ft, aim isn't as important because the target is much larger. It still takes considerable training to get two shots out in under 6 seconds.

kentma57
2007-12-15, 08:21 AM
Some one asked why you would want a rail gun, well it could be for chartcer concept (Artificer) and there is always use for a powerful long-range weapon, that can pass through anti-magic fields.

Wardog
2007-12-15, 11:46 AM
Quote:
Originally Posted by Wardog View Post
Now, I can imagine that you could also have a "siege weapon" railgun, that fired heavier projectiles at a slower rate, causing more damage overall; however I seriously doubt you would be getting nuclear bomb-equivilent damage.
No one is suggesting they would to that level of damage. However, the amount of energy in an object traveling 25km/h would be enough to put big holes in lots of stuff.

At least one person (Baxbart) was suggesting a railgun would be comparable to a thermonuclear explosion.





Quote:
Originally Posted by Wardog View Post
Nah - you're thinking of a .50BMG rifle/machinegun.

.50BMG - the Chuck Norris of the firearm world ;)


A useful railgun is more powerful than a machine gun, so it would be even worse. The more correct comparison is an artillery shell, just without the shrapnel.

That was meant as a joke. There are all sorts of wildly exaggerated myths circulating about .50BMG machineguns/rifles (e.g. they can tear someone's arm off/suck the air out their lungs just by missing them, they can shoot down airliners, the Geneva convention prohibits using them against enemy soldiers, etc).

Perhaps I should have compared them to katanas rather than Chuck Norris :)



I've thought of using recoil dampening spells on blunderbusses before. Though a railgun has no recoil. A gun has recoil because exploding powder goes in all directions, a railgun does not use stored energy (in chemicals or elastic materials) and only projects force in a single direction. A heat sink spell would be more useful. The problem with handheld railguns is not that they have recoil but that they're pea shooters.

A magic railgun in a D&D world would be a siege weapon for knocking down castle walls from a mile away, a ground to air emplacement weapon for taking out dragons or a weapon for picking off large creatures like giant's or dire mammoth's in whatever bizare fantasy army you're fighting.[/QUOTE]


As for projectile mass: you're right about speed being more important than mass for damage; kinetic energy = 0.5*m*v^2. However, would there be other benefits of using a more massive projectile? For example, would it be less affected/damaged by air resistance?


But really, I think this is probably for more technical than is needed for a fantasy setting.

I would suggest that a magical railgun would be a useful siege/ counter-siege/ naval / anti-dragon/etc weapon for a magic-technological society that lacked sufficiently high-level casters to simply create a +10 ballista, but did have access to a very large "magical power-supply", and sufficient "artificing" ability to overcome the real-world problems with railguns.

kentma57
2007-12-16, 08:41 AM
hmm.......

FlyMolo
2007-12-16, 01:09 PM
Could we stop the whole "railguns have no recoil" fallacy right here? Once and for all? Railguns use magnets, okay. But it doesn't matter. Magnets also obey fundamental laws. Basically, a railgun is using one magnet to push on another. If I hold one magnet in my hand and put it next to another magnet so that they repel, I'm going to feel a kick in my hand as the other magnet accelerates away. Look! Recoil! It may be a little hard to see, because railguns are bolted down, but there's recoil.
I've taken high school physics, and this is the FIRST thing they teach you. Right after the teacher's name. There's nothing mystical about magnetism which means it can violate physics, okay? Trust me. I've taken physics. So have some of you, I'll wager. And you know what? that annoys me. Because seriously people. RAILGUNS HAVE RECOIL! GET OVER IT!
Rant spoilered to protect the innocent.

Triaxx
2007-12-16, 03:49 PM
We're saying that you aren't going to notice the recoil the way you would from a shoulder carried rifle, or wheeled cannon. Since you have to brace the thing down the ground is what absorbs the impact.

On second thought, I wonder if you know how a railgun works? It's not two magnets pushing against each other. It's two large metal bars, and an electric charge. The 'round' is a conductive material which completes the circuit. The combination of heat from friction, and the electrical current is what discharges the round, and destroys the rails. The rails themselves are what absorb the recoil.

13_CBS
2007-12-16, 06:31 PM
Wait, what's the kind of gun that PULLS projectiles forward with magnets, then? That shouldn't have any recoil.

Heliomance
2007-12-16, 08:03 PM
YES! YES IT DOES HAVE RECOIL! NO MATTER HOW YOU'RE DOING IT, IF YOU APPLY A FORCE TO A PROJECTILE AND MAKE IT GO ONE WAY, YOUR GUN IS GOING TO RECEIVE A FORCE GOING THE OTHER WAY! EVERY ACTION HAS AN EQUAL AND OPPOSITE REACTION! EVERY! SINGLE! ACTION!


...sorry. If you're going to kill catgirls, at least do it right.

13_CBS
2007-12-16, 08:12 PM
YES! YES IT DOES HAVE RECOIL! NO MATTER HOW YOU'RE DOING IT, IF YOU APPLY A FORCE TO A PROJECTILE AND MAKE IT GO ONE WAY, YOUR GUN IS GOING TO RECEIVE A FORCE GOING THE OTHER WAY! EVERY ACTION HAS AN EQUAL AND OPPOSITE REACTION! EVERY! SINGLE! ACTION!


...sorry. If you're going to kill catgirls, at least do it right.

But how? If I stick a magnet in front of a metallic object, I feel no recoil until the object smacks into the magnet (which probably doesn't even count as recoil anyway).

Heliomance
2007-12-16, 08:16 PM
As the object approaches the magnet, you will feel the magnet pulling towards the object. If you let go of the magnet, it would move towards the object as well as the object moving towards the magnet. There is a force on both objects in opposite directions. If the projectile goes one way, the launcher goes the other.

Demented
2007-12-16, 08:52 PM
On second thought, I wonder if you know how a railgun works? It's not two magnets pushing against each other. It's two large metal bars, and an electric charge. The 'round' is a conductive material which completes the circuit. The combination of heat from friction, and the electrical current is what discharges the round, and destroys the rails. The rails themselves are what absorb the recoil.

I don't believe that's accurate.
But feel free to convince me with some documentation, if you'd like. :smallamused:

Heliomance
2007-12-16, 09:09 PM
It's more or less accurate. Rather simplified, but the basic idea's there. The heat isn't from friction though, I believe, but pretty much entirely from the massive electrical discharges involved. You want to get a projectile going that fast, you need some serious power behind it.

Demented
2007-12-16, 09:36 PM
Oops. I'd been under the impression that the projectile didn't need to contact the rails. That changes my perception of them a bit.

New idea: BEC-lined railguns. =P

kentma57
2007-12-16, 09:45 PM
At some point I should make a thread How do rail guns work?

Now untile I do that can we focus on more in-game matters, like how much damage will it do and how is the damage displayed (ex: explosion, punching holes, disintegration) and what type should it be(P,B,S)?

Triaxx
2007-12-16, 10:47 PM
Friction does generate a lot of heat though. Rub your hands together really fast, and you get a lot of heat. Imagine a supersonic round moving along a steel rail. Electric charge is only part of it.

On the other hand, there's talk of mounting them in place of standard Naval guns, because they can use power from the reactors on ships. The question then becomes: What coastal defenses?

Gamewise: Basically it travels to it's max range, inflicting 12d12 Force damage, with anything in it's path requiring a Fort Save or be instantly destroyed.

Demented
2007-12-16, 11:50 PM
Force damage seems a bit gratuitous. I'd just leave it as generic damage. On the other hand, I can't seem to find what's useful about force damage in the first place. *shrug*


On the other hand, there's talk of mounting them in place of standard Naval guns, because they can use power from the reactors on ships. The question then becomes: What coastal defenses?

Less gunpowder, safer ship.

Jack Zander
2007-12-17, 01:35 AM
Force damage?!?! I didn't know rail guns could harm ghosts.

NullAshton
2007-12-17, 02:09 AM
As the object approaches the magnet, you will feel the magnet pulling towards the object. If you let go of the magnet, it would move towards the object as well as the object moving towards the magnet. There is a force on both objects in opposite directions. If the projectile goes one way, the launcher goes the other.

Which isn't usually noticed because of the difference of mass between the magnet, and the small metallic object.

mabriss lethe
2007-12-17, 04:00 AM
Maybe a Line of Disintigration(as the spell disintigrate cast by an X level wizard) with an ungodly range increment? Normaly usable only once per hour, but allowing a single UMD check with an absurdly high DC to get it functional again before that hour elapses? If check succeeds then it can be fired after only a 15 minute interval. The weapon uses an iron ball as ammunition, So the effect can pass through a AMF, etc without noticable effect, but will be stopped by Repel Metal or Stone?
I dunno, just brainstorming

dyslexicfaser
2007-12-17, 04:54 AM
Force damage?!?! I didn't know rail guns could harm ghosts.

Have you ever tried shooting a ghost with a railgun?

Otherwise, how could you be sure?

Jack Zander
2007-12-17, 04:59 AM
Have you ever tried shooting a ghost with a railgun?

Otherwise, how could you be sure?

...

...

...

touche

Heliomance
2007-12-17, 05:27 AM
Which isn't usually noticed because of the difference of mass between the magnet, and the small metallic object.

Aye, but as force is mass times accelleration, and in a railgun the projectile is being given an unholy amount of accelleration, you're going to notice the recoil.

Belial_the_Leveler
2007-12-17, 05:43 AM
A DnD railgun needs the following:

Telekinesis use activated (100.000 gp)
Major Creation use activated (100.000 gp)


Basically, it would be a thick tube with a trigger. Point and shoot, magic takes care of the rest. On shooting, Major Creation conjures a 250 pound adamantine projectile which the telekinesis hurls doing 10d6 damage. You can direct the shot within a range of 100 ft (the range of telekinesis) but after that the object would move freely.

cascade
2007-12-17, 06:05 AM
Look, buddy, a rail gun has recoil--in fact, it has recoil equal to the potential energy in the projectile once the projectile is beyond the field effect of the rails. This potential energy is strictly greater than the projectiles eventual kinetic energy on impact--in other words, not only does a rail gun have recoil, it has more recoil than impact force.

Several other people here have mentioned equal and opposite reactions: these people are correct and you are wrong.

I have built a rail gun.

It is not physically possible to impart a force onto an object in this universe without 'having a place to stand'. In a rail gun, magnetic fields produce a field effect which rapidly accelerates a projectile along the rails--this is true, and this is true by definition. What you're not grasping is that these fields are "pushing" the projectile the same way that these fields are "pushing" themselves and the rails. This is why the rails in a rail gun produce two strong counter-forces beyond the force used to accelerate the projectile when firing--first, a 'vertical' force trying to force the rails apart (North/South, if you will); second, 'horizontal' force directed down the long axis of the rails (East). The N/S force acts on both rails in opposite directions; the East force is complimented by the West force of the projectiles acceleration.

The reason railguns are more attractive solutions than chemical-firearms is not because of a lack of recoil allowing higher potential energies, but instead because firearms are speed-restricted to the speed of sound at their operating pressure. I.e., since sound travels faster through denser substances, the maximum 'speed' of the projectile leaving the barrel of a chemical firearm is a function of the maximum sustainable pressure of the gun barrel. To increase bore-velocity, one must increase, vastly, the strength (material thickness, hardness, toughness, weight) of the firearm. Railguns are not limited in any way by the speed of sound--only by the speed of electrical/magnetic conductance/resistance of the rails--because the force they impart onto a projectile is not a consequence of a critical-gas 'shockwave', but is instead electro-magnetic.

This means that railguns can scale the potential energies of their projectiles then, not as a function of their operating pressure (i.e. bore strength), but instead, disregarding power concers, as a function of their rails length/strength. The engineering advantages become clear when you imagine how much easier it is to manufacture a strong steel beam when compared to a strong, steel, hollow sphere. For the same mass of steel, a beam is orders of magnitude more capable of maintaining structural integrity than a hollow globe subjected to an internal force directed outward in all directions approximately evenly.

Railguns have much greater potential to produce high operating energies--but this potential has nothing at all to do with a lack of recoil, and instead, has everything in fact to do with a rail being a much better dissipator of the recoil forces involved than a hollow ball.

As to your DnD railgun, you may elect to disregard as many laws of physics as you wish--just recognize that if equal-and-opposite goes, there would no longer be any hydro-static shock for projectile strikes. Moreover, a rail-projectile striking another mass at hyper-velocity would cut a perfectly clean hole into the ground without causing any collateral damage until slowed by friction. A magical railgun would certainly be capable to delivering a projectile at unbounded energies, especially if the speed-of-light is also no longer a limiting factor. I would point out that projectiles fired at or beyond escape velocity will not ever find a way to strike the planet, however, unless pointed at the ground (whether 3ft away, or 300 miles).

Good luck with your railgun. I suggest a railgun operating beyond the damage range of handheld weaponry be siege-class and appropriate to the physical artiface to whatever grade magicians are present.

Cas

P.s. I will happily submit for you a medely of sources to crossreference my claims if you so desire.

Darkone8752
2007-12-17, 07:57 AM
Cascade has alot of this right, and ill jsut add some of my knowledge of physics to this (sign'ed up to post here after reading comic and forums for a while :P)
Long descriptions with formulas, spoiler'ed to shorten reply :P
Recoil- True a railgun has recoil, but what people are trying to say, and just using the wrong words.
A gun, when fired, produces all its recoil in a very short amount of time. Even if its say a M16 and the bullet has a MV of 930M/s++ the accelleratio nis FAR higher then that. the bullets primary accelleration occures in a fairly smal lamount of time.
Railguns have the same recoil, but it isn't as noticable as a gun, because the acceleration is over a larger span of time.v^2 = u2 + 2as now, plugging in numbers using a barrel length of 20 inches for the m16, final velocity of 930 m/s. quote from a nice site that simplifies this all (http://hypertextbook.com/facts/2003/MichaelTse.shtml) Since acceleration is the desired value, the derived formula is this:
A=(v^2)/(2*s)
When fired from a Beretta 92S, the standard issue US Army pistol, a 9 mm Parabellum bullet has a muzzle velocity of 335 m/s. With its 127 mm barrel length, the bullet's acceleration is calculated to be 4.4 × 105 m/s2.
that works out to a m16 being A=930^2 / 2* .508 or 964,900/1.016= an acceleration of rougly 851,000m/s per second.


Aww damn, be back on tomarrow to finish post, i have to stop for now.

Skelengar
2007-12-17, 09:01 AM
The subject that this topic is about is the stats for a DND railgun, as opposed to the workings of a real life rail gun.

On that note, I think we already have perfectly good statistics.


Rail gun
This fearsome magical siege weapon was designed during a war between two magocracies, when one of the sides found itself attacking a city with walls of iron and antimagic fields in place. Using a combination of electrical evocations and telekinetic spells, it accelerates a large piece of metal to terrific speeds, tearing a swath of destruction in its wake. Of course, the ammunition must be carefully chosen, such that it does not simply disintegrate under the stresses created by the device.

Use: Activating it is a standard action. After firing, requires 1d4+1 rounds to recharge, and requires a full-round action spent to reload it.
Damage: 22d6, plus fortitude save DC 22 or be destroyed anyway. Dealt to each object in the shot's path (not just in the same square, though!), until maximum range has been reached or until something survives the damage dealt.
Cost: 60,000gp

Ammo options:
Iron - will travel 250ft before burning up. 1000gp
Iron/adamantine alloy - will travel 1000ft before burning up. 5000gp
Pure adamantine - would be nice, but you can't afford it.

To create: CL 15, chain lightning, telekinesis, reverse gravity, the usual cash and experience.

Balanced on disintegrate, with some tweaks.

Personally, I think that the fortitude save should increase on a crit, and that it should affect objects, as previously mentioned.

I'm also not sure if the ammo prices are per bullet or per x bullets.

Heliomance
2007-12-17, 09:20 AM
Awesome reply of accurate physics

<3
Major, major <3. Have my babies.

Belial_the_Leveler
2007-12-17, 12:45 PM
Damage: 22d6, plus fortitude save DC 22 or be destroyed anyway. Dealt to each object in the shot's path (not just in the same square, though!), until maximum range has been reached or until something survives the damage dealt.
None of the spell effects used in item creation has a save-or-die effect. None of the spell effects used in item creation is a line.


Cost: 60,000gp
A simple ring of telekinesis costs about the same and has much, much weaker effects.



To create: CL 15, chain lightning, telekinesis, reverse gravity, the usual cash and experience.
An item with the above spells all usable on activation would cost 540.000 gp. None of the above spells can give the desired effects.


Balanced on disintegrate, with some tweaks.
It is ALOT more powerful than disintegrate.

Closet_Skeleton
2007-12-17, 01:05 PM
Force damage?!?! I didn't know rail guns could harm ghosts.

d20 modern's ballistic damage is probably the relevent one.

Triaxx
2007-12-17, 01:10 PM
It is ALOT more powerful than disintegrate.

Even if you ignore that it ignores AMF's.

Heliomance
2007-12-17, 02:42 PM
None of the spell effects used in item creation has a save-or-die effect. None of the spell effects used in item creation is a line.


A simple ring of telekinesis costs about the same and has much, much weaker effects.



An item with the above spells all usable on activation would cost 540.000 gp. None of the above spells can give the desired effects.


It is ALOT more powerful than disintegrate.

So? I could probably build a functional rail gun with all those effects with precisely two spells: Chain lightning and Endure Elements (heat)

The thing to bear in mind is that the spells are being used indirectly. I'm not using chain lightning as an attack. I'm using chain lightning to create an electrical surge, which will create an immense motive force which will accelerate a chunk of metal in a straight line to a ridiculous speed. That speed means it won't stop for anything short of several feet of concrete, and then only maybe. It also means that anything it hits is going to have immense amounts of energy imparted to it which will result in huge damage. The shockwaves that this will cause to travel through the body are quite likely to rip it apart anyway, hence the save or die.

Darkone8752
2007-12-17, 10:05 PM
skipping my earlier reply because it isn't going to serve much purpose :P

okay, heres what im thinking of- seeing as this is magical lightning im going to assume it can harnass the full power of a natural lightning strike.

An average bolt of lightning carries a negative electric current of 40 kiloamperes (kA) (although some bolts can be up to 120 kA), and transfers a charge of five coulombs and 500 MJ, or enough energy to power a 100 watt lightbulb for just under two months. The voltage depends on the length of the bolt, with the dielectric breakdown of air being three million volts per meter; this works out to approximately one gigavolt (one billion volts) for a 300 m (1000 ft) lightning bolt. With an electric current of 100 kA, this gives a power of 100 terawatts.
So, yea, thats a LOT of power. With said spell and as mentioned above Endure Elements (Heat) it wouldn't be a far cry to say 10-25 KM/s.
Heres what i was thinking for the actual effect, tweak it for balance as I've never played real D&D (just baldurs gate, icewind dale, and neverwinter nights)
Any object within 10 feet of the bolts line of fire takes 2d4 damage with no save.
Any person in its line of fire must make a reflex save equal to 3x the damage dice of the lightning spell (ie if its normaly 10d6, the dc is 30). If they succeed they roll aside 5ft away from the bolts line of fire. If they fail, they must make a fort save equal to 2x the damage die of the lightning spell or be destroyed instantly. if they succeed they take damage equal to half lightning bolts base rounded down (as electrical) + a modifier for the ammo (iron would be an extra 6d6, steel would be 9d6, adamant alloyed would be 12d5, and solid adamantium - or maybe tungsten, not sure if its available in said campaign would do 15d6) as some sort of physical damage (like i said, someone has to tweak this :P). The bolt will always penetrate the first target in a line, but after that, any target that would survive it will stop it. Upon striking creature or object that can stop it (such as a wall or the ground) it deals regular damage as stated above to the target, and an additional 1+1d10 heat/fire damage per "level" of round (iron = 2d10, steel = 3d10, ect) to everything within X number of feet (maybe 20?).

heres a example. a lightning spell that normaly does 6d6 damage is used to fire a steel round. Everything within 10 feet of the round as it travels takes 2d4 damage. Lets say 3 soldiers are standing in its line. They roll a DC 18 reflex save, and only 1 succeeds. He jumps out of the way and takes regular 2d4. The first soldier rolls fort save dc 12 and fails, the second succeeds. He takes 3d6 electrical + 9d6 physical damage.11 electrical and 32 physical coming to 43 damage. Hes slaughtered instantly by the hit. Theres a wall a distance behind him with more soldiers 15 feet away from the impact area. The wall doesnt have to make a fort save, as its not a creature, so it takes regular damage and the wall, and everything within 20 feet takes 3d10 fire damage.

All a bit complicated but looks interesting and at least gives things a chance to survive. Cooldown could be like said before, 1d4+1 rounds, maybe if you upgrade it with a better spell for fighting off heat (or use very good rails, like adamant alloy) it would be reduced to 1d2 rounds. The endure elements spell would have to be recast every time, even if it was permanencied to account for the shear heat. The machine itself would be expensive, but iron and steel rounds would be very cheap as all they are is a rod, doesn't even have to be sharp, of metal.

Those talking about rail guns being weak- maybe a tiny weight at a low speed, but hersa lil osmething to wrap your minds around.
At 3000meters per second, an object packs a little over its own weight in TNT (4.5 megajoules).
Now, take 1 gram of adamantium, and whip it up to say 93% of the speed of light, and upon impact it will give off more energy then the most powerful nuclear weapon man has ever made, releasing about 55.7 megatonnes of TNT.

kentma57
2007-12-18, 09:15 PM
Darkone8752, briliant.

cascade
2007-12-18, 11:45 PM
A 1 kg mass traveling at 3,000 m/s does have 4.5 megajoules of kinetic energy, which is equivalent to 1 kg of TNT, this is true. But your calculations are wrong for the 1 g projectile. A 1 g projectile going the speed of light only has 45,000,000 megajoules of energy.

That's about 10 megatons of TNT, or somewhat near 20% of the Tsar Bomb.

Edit: For bad math, uh, twice.

D Knight
2007-12-18, 11:45 PM
hey you all forget about the ice/cold spells that a spellcaster might have. that to could stop some or alot of the fire damage to the rail gun when being fired so it could be fired sooner than befor (like 1-2 rounds sonner). but that is my thought on this and Darkone8752 i read ur post and that man is pure briliants if some one says other wise slap them (jk).

Darkone8752
2007-12-19, 12:11 AM
Thanks for all the praise y'all :smallredface:



A 1 kg mass traveling at 3,000 m/s does have 4.5 megajoules of kinetic energy, which is equivalent to 1 kg of TNT, this is true. But your calculations are wrong for the 1 g projectile. A 1 g projectile going the speed of light only has 45 megajoules of energy. That's about 20 pounds of TNT. Big whoop buddy.

?? where did yo uegt this from? newtons KE formula is ke=1/2 mass in kg * velocity in m/s^2. light moves at roughly a lil under 300,000,000 meters per second in a vaccuum(sp). even using the newtonian formula, you end up with over 10,975,000 KG of tnt (4.9290*10^13 joules) using einsteins formula from wikis page on RKV's (http://en.wikipedia.org/wiki/Relativistic_kill_vehicle) puts it at
Ek= ymc^2-mc^2
y= 1/ sqrt(1- V^2/c^2) using aproximate numbers of 300m M/s for c, 279m/300m = .93 sqrt of .07 = about .2645 1/.2645 = about 3.7807
Oh dam, just noticed the mistake, ill leave this here and do rest of solution in red.
279m^2/300m^2= .8649, 1-.8649 sqrt = .36755
1/.36755 = 2.72
Ek= 2.72*.001*300m^2 - .001*300m^2
ek= 1.548*10^14, or 34,400,000 kg-tnt
so, Ek= 3.7807*.001*300m^2 - .001*300m^2
ek= 2.50263x10^14. divide by 4,500,000 to get 55,614,000 kg
using the one from an awesome site on space combat to confirm it. (http://www.projectrho.com/rocket/rocket3x.html#rbomb)
Ker = ((1/sqrt(1 - P^2)) - 1) * M * 9e16 p=%speed of light, 93= .93
((1/sqrt(1 - .93^2))-1) * .001 * 9e16
((1/sqrt.1351)-1)
(2.72 - 1) * .001 * 9e16
1.5485 e14, same as above
edit 2: ok, made another mistake, was looking at my calc and seeing it as tons when it was only KG. cascade was about right, 37 KT-TNT
not jumping on ya, just asking you to point out if i made a mistake so i can correct it :P last time i went through a huge calc on some forums to prove that a dyson sphere is bad compared to fusion power or M/A-M reactors, i did a wrong number and ended up putting up 5grams of matter running a computer for 30 or so years, when it was really something like 3 million.

Btw when i say most powerful, i mean the actual yield recorded form the tsar bomb, not its maximum possible. Another note, i make so many typos that spellchecking is hell, so often i'll leave them.

cascade
2007-12-19, 12:18 AM
Hit the math again, fubard the order of operations--too much nog. See above. I figure 10mt TNT.

That's with Newton of course, which seems appropriate for DnD. It seems to me there's a whole slew of problems with this system though, and C really isn't on the table for any even siege class weapon system. Maybe interplanetary siege class. And still... a fusion bomb is 1950s engineering for the same effect.

Darkone8752
2007-12-19, 01:09 AM
heh yea, you can see with the new math in red i fixed some of it.
Still, the idea of an RKV is to throw a several hundred KG object at that speed... pretty nasty side effects on that one

All the energy put into achieving that velocity had transformed the Intruder into a kinetic storage device of nightmarish design. If it struck a world, every gram of the vessel’s substance would be received by that world as the target in a linear accelerator receives a spray of relativistic buckshot. Someone, somewhere, had built and was putting to use a relativistic bomb -- a giant, roving atom smasher aimed at worlds...

The gamma-ray shine of the decelerating half was also detectable, but it made no difference. One of the iron rules of relativistic bombardment was that if you could see something approaching at 92 percent of light speed, it was never where you saw it when you saw it, but was practically upon you...

In the forests below, lakes caught the first rays of the rising Sun and threw them back into space. Abandoning the two-dimensional sprawl of twentieth-century cities, Sri Lanka Tower, and others like it, had been erected in the world’s rain forests and farmlands, leaving the countryside virtually uninhabited. Even in Africa, where more than a hundred city arcologies had risen, nature was beginning to renew itself. It was a good day to be alive, she told herself, taking in the peace of the garden. Then, looking east, she saw it coming -- at least her eyes began to register it -- but her optic nerves did not last long enough to transmit what the eyes had seen.

It was quite small for what it could do -- small enough to fit into an average-sized living room -- but it was moving at 92 percent of light speed when it touched Earth’s atmosphere. A spear point of light appeared, so intense that the air below snapped away from it, creating a low-density tunnel through which the object descended. The walls of the tunnel were a plasma boundary layer, six and a half kilometers wide and more than 160 deep -- the flaming spear that Virginia’s eyes began to register -- with every square foot of its surface radiating a trillion watts, and still its destructive potential was but fractionally spent.

Thirty-three kilometers above the Indian Ocean, the point began to encounter too much air. It tunneled down only eight kilometers more, then stalled and detonated, less than two-thousandths of a second after crossing the orbits of Earth’s nearest artificial satellites.

Virginia was more than three hundred kilometers away when the light burst toward her. Every nerve ending in her body began to record a strange, prickling sensation -- the sheer pressure of photons trying to push her backward. No shadows were cast anywhere in the tower, so bright was the glare. It pierced walls, ceramic beams, notepads, and people -- four hundred thousand people. The maglev terminal connecting Sri Lanka Tower to London and Sydney, the waste treatment centers that sustained the lakes and farms, all the shops, theaters, and apartments liquefied instantly. The structure began to slip and crash like a giant waterfall, but gravity could not yank it down fast enough. The Tower became vapor before it could fall half a meter. At the vanished city’s feet, the trees of the forest were no longer able to cast shadows; they had themselves become long shadows of carbonized dust on the ground.

In Kandy and Columbo, where sidewalks steamed, the relativistic onslaught was unfinished. The electromagnetic pulse alone killed every living thing as far away as Bombay and the Maldives. All of India south of the Godavari River became an instant microwave oven. Nearer the epicenter, Demon Rock glowed with a fierce red heat, then fractured down its center, as if to herald the second coming of the tyrant it memorialized. The air blast followed, surging out of the Indian Ocean -- faster than sound -- flattening whatever still stood. As it slashed north through Jaffna and Madurai, the wave front was met and overpowered by shocks rushing out from strikes in central and southern India.

Across the face of the planet, without warning, thousands of flaming swords pierced the sky...

Then out of no where -- out of the deep impersonal nowhere -- came a bombardment that even the science fiction writers had failed to entertain.

Just nine days short of America’s tricentennial celebrations, every inhabited planetary surface in the solar system had been wiped clean by relativistic bombs. Research centers on Mars, Europa, and Ganymede were silent; even tiny Phobos and Moo-kau were silent. Port Chaffee was silent. New York, Colombo, Wellington, the Mercury Power Project and the Asimov Array. Silent. Silent. Silent.

A Valkyrie rocket’s transmission of Mercury’s surface had revealed thousands of saucer-shaped depressions where only hours before had existed a planet-spanning carpet of solar panels. The transmission had lasted only a few seconds -- just long enough for Isak to realize there would be no more of the self-replicating robots that had built the array of panels and accelerators, just long enough for him to understand that humanity no longer possessed a fuel source for its antimatter rockets -- and then the transmission had ceased abruptly as the Valkyrie disappeared in a silent white glare.

Presently, most of the station’s scopes and spectrographs were turning Earthward, and Isak found it impossible to believe what they revealed. The Moon rising over Africa from behind Earth was peppered with new fields of craters. The planet below looked like a ball of cotton stained grayish yellow. The top five meters of ocean had boiled off under the assault, and sea level air was three times denser than the day before -- and twice as hot...

The sobering truth is that relativistic civilizations are a potential nightmare to anyone living within range of them. The problem is that objects traveling at an appreciable fraction of light speed are never where you see them when you see them (i.e., light-speed lag). Relativistic rockets, if their owners turn out to be less than benevolent, are both totally unstoppable and totally destructive. A starship weighing in at 1,500 tons (approximately the weight of a fully fueled space shuttle sitting on the launchpad) impacting an earthlike planet at "only" 30 percent of lightspeed will release 1.5 million megatons of energy -- an explosive force equivalent to 150 times today's global nuclear arsenal... (ed note: this means the freaking thing has about nine hundred mega-Ricks of damage!)

The most humbling feature of the relativistic bomb is that even if you happen to see it coming, its exact motion and position can never be determined; and given a technology even a hundred orders of magnitude above our own, you cannot hope to intercept one of these weapons. It often happens, in these discussions, that an expression from the old west arises: "God made some men bigger and stronger than others, but Mr. Colt made all men equal." Variations on Mr. Colt's weapon are still popular today, even in a society that possesses hydrogen bombs. Similarly, no matter how advanced civilizations grow, the relativistic bomb is not likely to go away...

i must have something wrong somewhere, AR:SW put it as
5.5 x 1014 J: Relativistic weapon: 1 gram at 99% c = 132 kilotons

Ahh! jsut relised i was dividing by tnt, and seeing that as tons, when its only KG's! doh XD

Demented
2007-12-19, 03:01 AM
Aiming an RKV has got to be a pain. And they sure aren't going to correct their course if something changed in between the launch and the impact.

Darkone8752
2007-12-19, 04:58 AM
Aiming an RKV has got to be a pain. And they sure aren't going to correct their course if something changed in between the launch and the impact.

Heh, yes. Though its alot easier seeing as the thing moves so damn fast then trying to use for instance a space shuttle to mars XD.

Demented
2007-12-19, 06:07 AM
I'd say it's harder, since you're dealing with an object travelling at relativistic velocities, probably across a significant distance at a relatively insignificant target (planets are wee things on the stellar scale).

And, of course, there's the lack of error margin. Missing isn't just a minor problem, either. Because now you have this super-accelerated object heading FWEEE the way out with no particular aim. Yes, it's probably not going to hit anything, but also, yes, you've probably been launching hundreds, thousands, or more of them over the course of a war, and that probability adds up.

Which means you've got to catalog every single one of these that you launch, and keep an eye out for what might have an effect on their trajectory over the course of all time. Just in case you find a way to catch up to them, that is.


I also might mention that it always bugs me for this very same reason when they have these spaceships firing constantly in battles. Each and every one of these battles is going to have this expanding wave of cannonfire spreading outwards. Nobody ever seems to worry about that, not even a little bit.

Darkone8752
2007-12-19, 07:03 AM
Aye, in settings i rp on Starcraft, all the ships of my faction are fairly guarded against such things. IE they only use "conventional" (all some of said bombs make bigger bangs then nukes) weapons during atmospheric battles.
Theres extensive use of regular naval style cannons due to their ability to deliver extremely potent high explosives to an enemy alot easier then a missle. each shell, due to nanotech and cheap electronics has an auto-detonation system in it that blows the thing up if it misses.

Most of the battles occur under fairly normal speeds due to the "safe limit" on the crafts which is a limit placed on them normally, so they aren't travvling to fast to maneuver. Fighters are seen because (warning: handwavium and technobabble ahead) grav-shields, which are basicly a modification of grav-struts (aka nati-grav... to a certain weight limit) can cancel out some g forces on components, cushioning the pilots and allowing fighters to take avdantage of their massive thrust:weight ratios. Even a mid-range civilian craft, in the EARLY years of the setting can pull 20G's. Hyper-velocity cannons (aka, rail guns or the nastier AP rounds fired by some BB's) while they have no safety if they miss, of course rarely miss. energy weapons have a limited range before they expire, such as packeted plasma weapons losing the field that hold them together (im no physicist, but i know that plasma wont work in space unless contained). Lasers and A-M weapons arent seen due to (more handwavium, mixed with unobtanium) lasers being stoped by metals with insanely high emissive properties (transfering energy easily and absorbing alot of heat before vamporizing, leaking said energy back into space, ect ect) that make anything other then concentrated instant bursts useless. AM weapons having said fuel turned back into regular matter by a unique property in the shields.

Err... ok, back on topic- Noone has any tweaks for my idea? i thought it would be over/underpowered it seems O_o
Also, for the actual launcher, it would have a maximum usable damage die of lightning spells based on the components, like low grade iron 5d6, high grade 7d6, low steel 9d6, high steel 11d6, ect.

Heliomance
2007-12-19, 04:03 PM
A 1 kg mass traveling at 3,000 m/s does have 4.5 megajoules of kinetic energy, which is equivalent to 1 kg of TNT, this is true. But your calculations are wrong for the 1 g projectile. A 1 g projectile going the speed of light only has 45,000,000 megajoules of energy.

That's about 10 megatons of TNT, or somewhat near 20% of the Tsar Bomb.

Edit: For bad math, uh, twice.

Actually, no. You're forgetting relativity. A 1g projectile going at the speed of light has infinite energy. I can't be bothered to look up the formula to woork out how much energy it would have at 0.99 c, but it's in my notes somewhere.

EDIT: Wikipedia to the rescue.

E=(mc^2)/sqrt(1-v^2/c^2)

=(mc^2)/sqrt(1-(0.99c)^2/c^2)

=(0.01*(3*10^8)^2)/sqrt(1-((3*10^8*0.99)^2)/((3*10^8)^2))

=6.37*10^15 J

=6.37 thousand million MJ

So rather more than 45 million MJ.

D Knight
2007-12-19, 11:31 PM
hey i have what might be a silly question. but in D&D terms how much damage would the rails from the heat of firing. i ask this because i think i have found away to reduce or cancle the heat damage ut more on that later.

Heliomance
2007-12-20, 08:20 AM
It's called Endure Elements (heat)
Or Protection From Heat.

Magic will solve all your problems!

Admiral Squish
2007-12-20, 08:24 AM
This is both a catgirl massacre and the most beautiful thing I've seen created in a long time. A RAILGUN. In D&D. This should be abjectly terrible. But it's good!

kentma57
2007-12-20, 08:31 AM
This is both a catgirl massacre and the most beautiful thing I've seen created in a long time. A RAILGUN. In D&D. This should be abjectly terrible. But it's good!

Thank you, Admiral Squish.

Beleriphon
2007-12-20, 08:44 AM
A Glitter Boy's Boom gun deals 4d6 MDC; that sounds about right to me.

4d6x20 MDC, the x20 part is very important.