Railgun Type Weapons

[MythSearcher]

(Of course, since Thunderbolt is its own thing largely separate from the UC proper we'll likely never know due to a lack of continued exploration of that alternate UC setting.)

Yeah, where'd they find a ball that small in the torso? Even the SP-W03 is bigger than that.

[Kuruni]

Think about it, I think the first animate MS equipped with rail cannon (not counting the shot lancer) seems to be Gozzo from Turn A Gundam, and no other suit use it. When the Earth Militia modified it into Godwin, they naturally don't have such weapon and replace it with a mundane cannon (the official site state that it's a machine gun, but I remember a book scan claims it's an anti-aircraft cannon).

Probably worth to note that aside of Dainslef, all Pluma (Hashmal's lackeys) are also equipped with a railgun, and Bael has electromagnetic gun in its binders. As McGillis notes, l railgun shooting normal ammo is still legal, if borderline, weapon.

Based on the official Mechanics and World books for IBO, railguns were the projectile weapon of choice during the Calamity War era because nanolaminate armor technology made conventional cannons ineffectual except at very close range. The much higher muzzle velocities railguns could achieve were necessary to overcome nanolaminate armor's defensive ability at longer ranges, though special armor-piercing ammunition (like Dainsleif rounds) was required for true long-range engagements.

Gjallarhorn banned many technologies related to the Calamity War after the war ended, including production of Ahab reactors, Dainsleif rounds, etc. in the name of maintaining public order and preventing any more mass destruction like what'd happened to the Moon under mass Dainsleif bombardment. With Mobile Armors gone, Mobile Suits on the decline, and Dainsleif rounds to use against them banned, there wasn't much call for any railguns, so that technology atrophied over the next three centuries like the once-critical Alaya-Vijnana system. The ones used by the Barbatos Lupus and Iok Kujan's Reginlaze were new production prototypes, while the others are old weapons maintained by Gjallarhorn "just in case". Gjallarhorn didn't need them in its day-to-day business since it was "kicking down" at increasingly obsolete Mobile Suits and Mobile Workers that had no nanolaminate armor.

Ah! I completely forgot about Iok's railgun and how the pirates comment about its incredible range. Ironically, this mean the one time people actually remark about Iok's sniping ability, it's still more of his gun and less about his skill XD .

[Seto Kaiba]

Think about it, I think the first animate MS equipped with rail cannon (not counting the shot lancer) seems to be Gozzo from Turn A Gundam, and no other suit use it. When the Earth Militia modified it into Godwin, they naturally don't have such weapon and replace it with a mundane cannon (the official site state that it's a machine gun, but I remember a book scan claims it's an anti-aircraft cannon).

At that caliber, the difference between a cannon and an anti-aircraft piece is the type of ammunition you load into it and not a lot else.

For whatever reason, railguns were relatively rare in the mecha genre until the mid-90's and kind of faded into obscurity again at the end of the 2000's. Almost every Earth mecha was armed with railguns in the Macross II: Lovers Again OVA (1992), they're mentioned in passing in Turn A Gundam and a bunch of 90's MSV stuff, the tank-equivalents in Five Star Stories, etc. Then in the 2000's they got downgraded to railgun tech as an assist system like the VF-25's sniper rifle in Macross Frontier and the weird combination pneumatic/railgun firearms in Code Geass. The last holdouts were probably 00's Enact and Union Flag, which made their railguns practical via external power sources.

Ah! I completely forgot about Iok's railgun and how the pirates comment about its incredible range. Ironically, this mean the one time people actually remark about Iok's sniping ability, it's still more of his gun and less about his skill XD.

Ironically, the one time he should've been useful is the one time he's most useless... when the Mobile Armor Hashmal no-sells fire from his Reginlaze Kai's railgun because he's not using AP ammo.

[Kuruni]

For whatever reason, railguns were relatively rare in the mecha genre until the mid-90's and kind of faded into obscurity again at the end of the 2000's. Almost every Earth mecha was armed with railguns in the Macross II: Lovers Again OVA (1992), they're mentioned in passing in Turn A Gundam and a bunch of 90's MSV stuff, the tank-equivalents in Five Star Stories, etc. Then in the 2000's they got downgraded to railgun tech as an assist system like the VF-25's sniper rifle in Macross Frontier and the weird combination pneumatic/railgun firearms in Code Geass. The last holdouts were probably 00's Enact and Union Flag, which made their railguns practical via external power sources.

Hmm...when it come to railgun in mecha anime, the first to pop in my mind is Metal Armor Dragonar. If we count adaption, SRW OG: The Inspector does features some railgun used by AM and the R-Blade.

[Mafty]

The whole Animated Canon thing can get kind of vague (i.e., is Astray canon because it has animated commercial shorts?), and sometimes it seems like some of the weapons/locations don't exist outside of side materials (has the California Base actually been mentioned in any of the Anime?).

Considering the concept of a Railgun dates back to 1917, it hardly seems like it was too new of a concept to appear in earlier works.

It might be a harder concept to work with in space settings, however in that case Beam Weaponry shouldn't be able to work either.

As for railguns in Mecha's, would Broken Blade count? The Golems use no beam weaponry at all(at least in the Anime), and regularly fire pressurized bullets and weaponry in combat.

On another note, how exactly are Shot Lancers retrieved? Unlike the rest of the Railguns they fire a more permanent projectile, into a unit that is often destroyed. Wouldn't they quickly run out of ammunition?

[D_I]

The shot lancer projectile might be held on with a wire that can be pulled back with a winch

[Seto Kaiba]

Hmm...when it come to railgun in mecha anime, the first to pop in my mind is Metal Armor Dragonar. If we count adaption, SRW OG: The Inspector does features some railgun used by AM and the R-Blade.

The oldest reference I recall - mentioned but not used - is in Super Dimension Fortress Macross. The titular ship has four MASSIVE anti-capital ship railguns that it never actually uses.

It might be a harder concept to work with in space settings, however in that case Beam Weaponry shouldn't be able to work either.

Much like an energy weapon, a railgun should work substantially better in space because the projectile wouldn't be losing energy and accuracy due to the friction of atmospheric gases and the influence of local gravity.

It wouldn't just be more accurate, the kinetic penetrator would actually be moving faster without air friction slowing it down. (Though I only know of one series that actually acknowledges this fact explicitly, that being Macross Frontier.)

(Energy weapons suffer in a similar fashion in atmosphere, with the beam losing energy to the atmospheric gases it passes through and becoming defocused by changes in temperature and density in the gases that it's passing through, a phenomenon called thermal blooming.)

As for railguns in Mecha's, would Broken Blade count? The Golems use no beam weaponry at all(at least in the Anime), and regularly fire pressurized bullets and weaponry in combat.

If it's using pressurized gas, that's a pneumatic weapon.

[MythSearcher]

Considering the concept of a Railgun dates back to 1917, it hardly seems like it was too new of a concept to appear in earlier works.

It might be a harder concept to work with in space settings, however in that case Beam Weaponry shouldn't be able to work either.

Beam works because they travel much faster.
Even if not talking about electro-magnetic beams, particle beams can travel much much faster than solid projectiles, thus if we only consider the time they need to travel in long space distance like a few dozen to hundreds or maybe even tens of thousands of kilometres, you can pretty much only use beam and not solid projectiles.


Also a pretty simple reason why railguns aren't used a lot in stories is likely because the lack of news and development and it's relatively mundane result of basically also only firing a solid projectile like conventional, traditional firearms.
Yes, Sci-fi writers like to use the newest and fanciest technologies in development, most don't go and check out older scientific papers for ideas.
While yes, all the way back in 1917 and 1923 or maybe as late as after WWII you get some development of the railgun, but then you don't get a lot until the 80's where the military took some interest in it and started more development, which likely only influenced anime in the 90s.
It is also not really that impressive to have yet another shell firing weapon unless you see the video of the US Navy railgun having that long trail of smokey fire tail behind the projectile(which actually shows how inefficient the thing is but LOOKS cool). The term sound more outdated than futuristic and will take more resources to animate like firearms and even harder to depict since you cannot just draw muzzle flash and shells being ejected.
This is why most TV anime use beam and you only see more shell firing guns in OVA and movies. It is also for saving the hassle to teach kids how shell firing guns work and easy to colour code the projectiles. In SEED Freedom's waist railgun is just depicted like a regular beam shooting gun because they don't bother telling the difference.

I was wondering how many Railgun style weapons exist in the Universal Century. The only one I know of is the one that the Atlas Gundam uses.
Is there any advantage to having a railgun instead of a beam or shell firing weapon?
I'd assume it would be effective for stealth purposes since beams are so bright and can draw attention to the MS using the beam weapon.
for an example there is the scene with the Zaku sniper in Unicorn where the beam is practically a pillar of light coming down from the sky.

And now, as no one has mentioned it yet, Jormungand is basically half a railgun. Just that it is so powerful that it turn it's projectile into plasma before it even exits the barrel.

[Seto Kaiba]

Beam works because they travel much faster.
Even if not talking about electro-magnetic beams, particle beams can travel much much faster than solid projectiles, thus if we only consider the time they need to travel in long space distance like a few dozen to hundreds or maybe even tens of thousands of kilometres, you can pretty much only use beam and not solid projectiles.

It depends on the setting, really.

In real world terms, yes... particle beams travel much faster than any conventional projectile but that's basically their only significant advantage. Damage is all about the quantity and transfer time of kinetic energy, so to deal significant damage a particle beam needs to either have a prolonged irradiation time or an excessively high output and run into complications like loss of beam energy to ablated material from the target's surface "fogging" the beam.

In fiction, well, it's not always the case. Sci-fi writers love their slow-moving energy "bolts" like those from Star Wars's blaster and laser weapons, many weapons in Star Trek, and of course occasionally various mega-particle beam weapons in Gundam.

Mind you, in popular sci-fi most combat between spacecraft occurs at distances of a few kilometers to a few tens of kilometers at most rather than hundreds or thousands of kilometers. At those distances, there isn't really much difference between a railgun and a beam weapon for accuracy and you can conceivably do a lot more damage for the same energy with the railgun.

Also a pretty simple reason why railguns aren't used a lot in stories is likely because the lack of news and development and it's relatively mundane result of basically also only firing a solid projectile like conventional, traditional firearms.
Yes, Sci-fi writers like to use the newest and fanciest technologies in development, most don't go and check out older scientific papers for ideas.
While yes, all the way back in 1917 and 1923 or maybe as late as after WWII you get some development of the railgun, but then you don't get a lot until the 80's where the military took some interest in it and started more development, which likely only influenced anime in the 90s.
It is also not really that impressive to have yet another shell firing weapon unless you see the video of the US Navy railgun having that long trail of smokey fire tail behind the projectile(which actually shows how inefficient the thing is but LOOKS cool). The term sound more outdated than futuristic and will take more resources to animate like firearms and even harder to depict since you cannot just draw muzzle flash and shells being ejected.
This is why most TV anime use beam and you only see more shell firing guns in OVA and movies. It is also for saving the hassle to teach kids how shell firing guns work and easy to colour code the projectiles. In SEED Freedom's waist railgun is just depicted like a regular beam shooting gun because they don't bother telling the difference.

In all likelihood, this probably has a lot more to do with certain audience expectations built up gradually over the years by decades of pop sci-fi works starting from titles like War of the Worlds and the old television serials like Flash Gordon where "ray guns" were the futuristic weapon of choice. That association between energy weapons as inherently emblematic of sci-fi has been built up by decades of repeated association.

Mind you, there may also be an element of "west vs. east" and of "hard vs. soft" sci-fi in play. Western sci-fi tends to use railguns with considerably greater frequency than Eastern sci-fi, though they also tend to show up in titles that are either aimed at more mature audiences, more "gritty", or simply ones that take the science aspect of sci-fi more seriously. In some cases, they're actually ubiquitous but simply not mentioned directly as the result of either displacing the details into supporting publications or the sheer ubiquity itself. For instance, every torpedo launcher in Star Trek is a railgun but it almost never comes up or in Code Geass the tech is in every firearm and just never commented on. They're quite common in Stargate, Andromeda, referenced as WMDs in Babylon 5, the default form of Imperial, Chaos, and Tau starship weaponry in Warhammer 40,000 and are also some of the nastiest large-scale weapons in the setting, the default human starship weapon in Halo, they're used for long-range attacks in Metal Gear, used as powerful anti-aircraft weapons in Ace Combat, etc. Since Gundam set the norm for robot anime in Japan and it went in for beam weapons, that's just the norm there.

And now, as no one has mentioned it yet, Jormungand is basically half a railgun. Just that it is so powerful that it turn it's projectile into plasma before it even exits the barrel.

That's not accurate. The Jormungand is just an inordinately inefficient plasma cannon that predates the development of proper mega-particle weapons. The firing mechanism just overloads a Minovsky-Ionesco reactor inside the barrel and corrals the resultant explosion into a projectile using magnetic fields.

[MythSearcher]

It depends on the setting, really.

In real world terms, yes... particle beams travel much faster than any conventional projectile but that's basically their only significant advantage. Damage is all about the quantity and transfer time of kinetic energy, so to deal significant damage a particle beam needs to either have a prolonged irradiation time or an excessively high output and run into complications like loss of beam energy to ablated material from the target's surface "fogging" the beam.

Actually, even irl other than laser, particle beams are not very likely to work. They will scatter fast enough that you won't get much longer range than solid projectiles.(they scatter at the speed of sound of that particle) and also, damage relies on the momentum, in which a light weighted particle beam carries little of. It may do some damage if really focused, but as above, they scatter really fast.

and then since it got little momentum, it gets blocked by very simple stuff like you said. and simply increasing the energy density will cause blooming even on regular, non-ablative surfaces to block following beam, so yeah, irl it is also not very likely to be really useful.

In fiction, well, it's not always the case. Sci-fi writers love their slow-moving energy "bolts" like those from Star Wars's blaster and laser weapons, many weapons in Star Trek, and of course occasionally various mega-particle beam weapons in Gundam.

Mind you, in popular sci-fi most combat between spacecraft occurs at distances of a few kilometers to a few tens of kilometers at most rather than hundreds or thousands of kilometers. At those distances, there isn't really much difference between a railgun and a beam weapon for accuracy and you can conceivably do a lot more damage for the same energy with the railgun.

If you look at the big picture, literally, the beam travels long distance in pretty much the same relative on screen distance, some obviously going even faster than light, some slower than your typical bullet.

That's not accurate. The Jormungand is just an inordinately inefficient plasma cannon that predates the development of proper mega-particle weapons. The firing mechanism just overloads a Minovsky-Ionesco reactor inside the barrel and corrals the resultant explosion into a projectile using magnetic fields.

iirc it launches the reactor with a railgun in the first half of it and overloads it in the middle.

[Underrated GM Custom]

Regarding railguns in UC is there any information out there regarding the railgun / railcannon used by the Desert GM and the Land Combat GM from MSV? Both share the RGM-79F model number. I recall hearing that railguns were developed by Yashima industries as a stopgap while the Federation was still miniaturizing beam weapons for use by MS.

[Seto Kaiba]

Actually, even irl other than laser, particle beams are not very likely to work. They will scatter fast enough that you won't get much longer range than solid projectiles.(they scatter at the speed of sound of that particle) and also, damage relies on the momentum, in which a light weighted particle beam carries little of. It may do some damage if really focused, but as above, they scatter really fast.

Technically speaking, its range will be inferior to the kinetic round because the kinetic round will continue moving at speed until it either hits something or enters a gravitational field intense enough to trap it in a decaying orbit. It's a problem not often discussed, but actually did get a mention toward the end of G-Witch's Part I.

In that light, the limited effective range of a particle beam may actually be a virtue in the long term. Of course, a big part of the problem is simply that modern technology simply can't collimate particle beams anywhere near well-enough to be useful as a weapon or at anywhere near the required power level to do immediate harm without a particle accelerator that's literally tens of kilometers long. Neutral particle beams offer a better potential for weapons use, since they won't defocus quite as readily due to mutual repulsion among like-charged particles. Sci-fi future tech could conceivably make it practical over the kind of distances we see in pop sci-fi, though whether it'd actually be more effective than a kinetic cannon is debatable at best.

iirc it launches the reactor with a railgun in the first half of it and overloads it in the middle.

Can't find any mention of that aspect of it specifically.

Regarding railguns in UC is there any information out there regarding the railgun / railcannon used by the Desert GM and the Land Combat GM from MSV? Both share the RGM-79F model number. I recall hearing that railguns were developed by Yashima industries as a stopgap while the Federation was still miniaturizing beam weapons for use by MS.

It does have a writeup in Master Archive Mobile Suit: RGM-79 GM Vol.2.

In a somewhat amusing touch, the YHI YF-RC180 is described as quite literally being an old naval cannon designed for previous-generation warships that was hastily retrofitted with a self-contained ammo feed and grip for Mobile Suit use. It's said that it was (hastily) developed by Yashima Heavy Industrial in part because the initial-type beam spray gun developed for the RGM-79 GM proved to be unreliable and prone to malfunction in cold weather. Master Archive describes it as "technically inferior to beam weapons" but indicates that it demonstrated superior reliability as a weapon and a high operational rate due to the technology behind the railgun being more mature than mega particle weaponry. It holds somewhere between 4 and 8 180mm KEPs and has stopping power far in excess of MS-carried machine guns. The smaller YF-RC155 railgun made for the RGM-79F Desert GM was developed after the YF-RC180 for reduced size and easier handling, allowing YHI to use surplus Type-61 tank barrels for the weapon and a sub-weapon was mounted to compensate for its reduction in stopping power. (Options mentioned include a 4-tube missile launcher, 8-tube short-range missile launcher, and super napalm dispenser.)

[MythSearcher]

Technically speaking, its range will be inferior to the kinetic round because the kinetic round will continue moving at speed until it either hits something or enters a gravitational field intense enough to trap it in a decaying orbit. It's a problem not often discussed, but actually did get a mention toward the end of G-Witch's Part I.

In that light, the limited effective range of a particle beam may actually be a virtue in the long term. Of course, a big part of the problem is simply that modern technology simply can't collimate particle beams anywhere near well-enough to be useful as a weapon or at anywhere near the required power level to do immediate harm without a particle accelerator that's literally tens of kilometers long. Neutral particle beams offer a better potential for weapons use, since they won't defocus quite as readily due to mutual repulsion among like-charged particles. Sci-fi future tech could conceivably make it practical over the kind of distances we see in pop sci-fi, though whether it'd actually be more effective than a kinetic cannon is debatable at best.

Depends on what you are considering as effective range.
If your target has any reasonable acceleration, a projectile that will only hit 30s later is not very likely to hit, thus even if it remained as fully effective as a projectile if it hits, we don't consider that as effective range.

A solid projectile have a much longer effective kill range if it can hit that target, so if we are talking about a target that cannot have a lot of acceleration on its own, like a space station or large enough spaceship, we can count on that effective range.
A particle beam moves faster, so it covers a longer range, but at the same time the effectiveness reduces as it travels, but within the range it can be energetically effective, it should have a better chance of hitting a target with higher acceleration than a solid projectile.

And while neutral beams will be better, they still scatter at the speed of sound of that medium because it is just a matter of pressure difference against the vacuum of space.

But in any sense, if we are shooting something like a stream of high temperature particles, here are the numbers:
from ATOMIC ROCKETS

Dr. Geoffrey A. Landis had this to say:

Particle beams disperse for a lot more reasons than laser beams, unfortunately, so it's harder to give a simple formula. It will depend on things like magnetic and electric fields in the region between the source and the target (if the particles have spin, for example, they will couple to the magnetic field gradient even if they are neutral).

However, for a neutral particle beam traversing empty, field-free space, the dispersion is proportional to the temperature of the beam. Using, for the sake of a simple example, a mercury ion beam (dispersion decreases proportional to square root of atomic mass, and mercury is a convenient high-mass atom that ionizes easily), the lateral (spreading rate) velocity of the beam is:

V = 1.4 SQRT(T) m/sec, for T in Kelvins

To calculate the actual angular spread of the beam, you need to know the beam velocity. For a quick calculation, you could say it's no more than the speed of light, 300,000,000 m/sec. So the dispersion in nano-radians is 5 SQRT(T).

So, for a beam with an effective temperature of, say, 1000K, dispersion for mercury is 150 nR, or 0.15 micro-radians. Dispersion at a distance of 100,000 km would be 0.015 km, or 15 meters. A hydrogen beam would disperse SQRT(80)= 9 times more.

[note that if the beam is actually relativistic, you have to apply a relativistic correction, which I'll ignore here.]

So in any sense, space battle will likely be people shooting lasers at each other until they expend all their defensive measures and heat sink and pull out white flags before melt down.

[Seto Kaiba]

Depends on what you are considering as effective range.
If your target has any reasonable acceleration, a projectile that will only hit 30s later is not very likely to hit, thus even if it remained as fully effective as a projectile if it hits, we don't consider that as effective range.

"Effective range" is entirely subjective in those terms... it depends on what the established norms for combat range are in space based on the technology available at the time. As technology improves, those ranges will likely increase, much as how the advent of rifling increased the effective range of late 18th and early 19th century long rifles from 75-100m to over 200m. Not to mention that the same principles for shooting at moving targets apply whether the target is 10 meters away or 100,000 kilometers. As long as you know its direction of travel, velocity, and acceleration, you can lead the target and land a hit.

(Not to mention there's not really anything preventing a railgun from using more than just a single, solid kinetic energy penetrator. Something like blast-fragmentation shells or AHEAD rounds could easily be used in that same environment to increase the probability of a hit at long ranges, much as they've been used against aircraft by ground emplacements for a century.)

This sort of thing is often acknowledged by science fiction writers when railguns are depicted as spacecraft weapons... having to lead the target or estimate the travel time of a railgun-fired explosive with a timed fuse to ensure that a hit is confirmed. (Perhaps the best example of this mechanic in practice is Warhammer 40,000's spinoff game Battlefleet Gothic, which requires exactly that from players using certain weapons.)

So in any sense, space battle will likely be people shooting lasers at each other until they expend all their defensive measures and heat sink and pull out white flags before melt down.

Assuming, of course, that range is no object... space combat isn't really a thing in the real world yet, but all things considered it's far more likely to take the form of guided missile strikes at least at first since that's what the bulk of surface-to-orbit weapons currently are.

[MythSearcher]

"Effective range" is entirely subjective in those terms... it depends on what the established norms for combat range are in space based on the technology available at the time. As technology improves, those ranges will likely increase, much as how the advent of rifling increased the effective range of late 18th and early 19th century long rifles from 75-100m to over 200m. Not to mention that the same principles for shooting at moving targets apply whether the target is 10 meters away or 100,000 kilometers. As long as you know its direction of travel, velocity, and acceleration, you can lead the target and land a hit.

(Not to mention there's not really anything preventing a railgun from using more than just a single, solid kinetic energy penetrator. Something like blast-fragmentation shells or AHEAD rounds could easily be used in that same environment to increase the probability of a hit at long ranges, much as they've been used against aircraft by ground emplacements for a century.)

This sort of thing is often acknowledged by science fiction writers when railguns are depicted as spacecraft weapons... having to lead the target or estimate the travel time of a railgun-fired explosive with a timed fuse to ensure that a hit is confirmed. (Perhaps the best example of this mechanic in practice is Warhammer 40,000's spinoff game Battlefleet Gothic, which requires exactly that from players using certain weapons.)

The lead cannot be effective if your projectile cannot reach the target distance before your target can well have changed direction and very likely will.
I guess ship battle is much more lenient as they don't really expect a high hit rate(I play warship games and know historical hit rates of ships), but still, waiting for a projectile to fly for over 30s to hit something the size and acceleration of a plane without precision guidance wouldn't be effective. Not even 5s sound effective in this situation unless you are firing shrapnel, and space is huge and shrapnel doesn't work well far away from the explosion centre.

Assuming, of course, that range is no object... space combat isn't really a thing in the real world yet, but all things considered it's far more likely to take the form of guided missile strikes at least at first since that's what the bulk of surface-to-orbit weapons currently are.

well, yes, if it is still just orbital combat then guided missiles is likely the main weapon. Laser can still be very effective though, considering how little mass we can put into orbit and missiles will take up a much more major mass than a laser and a laser can be continuously powered by solar panels.

[Kuruni]

Fun trivia.

In Mika Akitaka's MS Girl Note, Gundam has her hyper bazooka upgraded to rail gun with G-3 armor. Guncannon also has rail guns from start.

Unfortunately, I don't think we'll ever got translated detail about this series.

[Seto Kaiba]

The lead cannot be effective if your projectile cannot reach the target distance before your target can well have changed direction and very likely will.

While this is true, it doesn't really account for the fact that spacecraft are themselves naturally disinclined to swift changes of velocity or direction... particularly in orbit. (Fictional ones aside.)

I guess ship battle is much more lenient as they don't really expect a high hit rate(I play warship games and know historical hit rates of ships), but still, waiting for a projectile to fly for over 30s to hit something the size and acceleration of a plane without precision guidance wouldn't be effective. Not even 5s sound effective in this situation unless you are firing shrapnel, and space is huge and shrapnel doesn't work well far away from the explosion centre.

It's all about how quickly the projectile's moving... 2km/s is fine here on Earth where line-of-sight engagement ranges are ~4.5km due to having to consider the curvature of the Earth. Without atmospheric gases in the way, and/or with higher-powered capacitors and higher system voltages, a railgun can perform far beyond that level and is only really limited by the properties of the conductor used to make the rails. With technologies like superconductors and super-hard alloys in play, and with no atmospheric gases to compensate for, far greater velocities are in play.

This, of course, is taken to its logical extreme in some sci-fi titles that have perfected railgun and coilgun technology to the point of being able to achieve relativistic projectile speeds. This is featured prominently in the Warhammer 40,000 setting as one of the dominant forms of naval cannon and in Halo as the main/heaviest weapon on most warships and space stations. The orbital defense MAC platforms in Halo 2's setting are throwing projectiles at 0.04c, while the Imperial (and Chaos) gun batteries and nova cannons are throwing shells at close to lightspeed.

well, yes, if it is still just orbital combat then guided missiles is likely the main weapon. Laser can still be very effective though, considering how little mass we can put into orbit and missiles will take up a much more major mass than a laser and a laser can be continuously powered by solar panels.

Which is a conclusion that tracks with what's been said about the Earth Federation Space Forces before the advent of Minovsky particles and beam weapons... as an overwhelmingly powerful force with shocking long range potential built on railguns and radar-guided missiles.

[MythSearcher]

While this is true, it doesn't really account for the fact that spacecraft are themselves naturally disinclined to swift changes of velocity or direction... particularly in orbit. (Fictional ones aside.)

If you see a flash under hostile conditions, you will try to change direction.
and it doesn't take much to change enough to get out of the way the longer it take for the projectile to hit as the distances are great and only a very slight angle change still can mean you are a few dozen metres off of your original course.

It's all about how quickly the projectile's moving... 2km/s is fine here on Earth where line-of-sight engagement ranges are ~4.5km due to having to consider the curvature of the Earth. Without atmospheric gases in the way, and/or with higher-powered capacitors and higher system voltages, a railgun can perform far beyond that level and is only really limited by the properties of the conductor used to make the rails. With technologies like superconductors and super-hard alloys in play, and with no atmospheric gases to compensate for, far greater velocities are in play.

This, of course, is taken to its logical extreme in some sci-fi titles that have perfected railgun and coilgun technology to the point of being able to achieve relativistic projectile speeds. This is featured prominently in the Warhammer 40,000 setting as one of the dominant forms of naval cannon and in Halo as the main/heaviest weapon on most warships and space stations. The orbital defense MAC platforms in Halo 2's setting are throwing projectiles at 0.04c, while the Imperial (and Chaos) gun batteries and nova cannons are throwing shells at close to lightspeed.

Railgun's inherent limit is the friction between the projectile and the rail, the length of the rail is also a limiting factor. You can get to far greater velocities but friction will heat up the rail and the projectile, and you don't want it to melt, burn, or even just heat to a point where it softens and throws off your aim. So you have a max velocity it can get relative to the friction between the projectile and the rail. Then you need to consider recoil, which also throws off aim, and if you try to solve it with a longer rail, the projectile is also going to have longer contact and thus heats up more, and the longer rail has a higher chance to deform, thus also throws off aim.
Yes, you can get to far greater velocities, but not very likely into something like 100km/s levels even on large warships.

Which is a conclusion that tracks with what's been said about the Earth Federation Space Forces before the advent of Minovsky particles and beam weapons... as an overwhelmingly powerful force with shocking long range potential built on railguns and radar-guided missiles.

Well, Mega particle cannons are said to be 4 times as efficient than lasers and Minovsky particles make it impossible to detect and hit something in those distances, so they don't need that long range any more to begin with.

[Underrated GM Custom]

Thanks for the information on the RGM-79F Railguns. So if they were repurposed Naval Weapons does that mean the older Salamis or its predecessor was using railguns prior to the introduction of Mega Particle Cannons?

[Seto Kaiba]

If you see a flash under hostile conditions, you will try to change direction.
and it doesn't take much to change enough to get out of the way the longer it take for the projectile to hit as the distances are great and only a very slight angle change still can mean you are a few dozen metres off of your original course.

True, though there are ways to suppress muzzle flashes... and railguns in a vacuum are going to be naturally less inclined to produce once since the system has no flammable/explosive propellant driving the shell.

Of course, "great distances" is relative and ability to change direction is going to be dependent on things like the ship's inertial mass, speed, and other considerations like orbital mechanics.

Railgun's inherent limit is the friction between the projectile and the rail, the length of the rail is also a limiting factor. You can get to far greater velocities but friction will heat up the rail and the projectile, and you don't want it to melt, burn, or even just heat to a point where it softens and throws off your aim. So you have a max velocity it can get relative to the friction between the projectile and the rail. Then you need to consider recoil, which also throws off aim, and if you try to solve it with a longer rail, the projectile is also going to have longer contact and thus heats up more, and the longer rail has a higher chance to deform, thus also throws off aim.
Yes, you can get to far greater velocities, but not very likely into something like 100km/s levels even on large warships.

Leaving aside coilguns, which are often incorrectly conflated with railguns despite working on different principles, there are approaches to railguns in the real world that do not suffer from that particular friction problem. Plasma armature railguns do not have the projectile in physical contact with its rails, using instead a vaporizing metallic foil to establish an electrical arc across the projectile and keep it suspended in the middle of the barrel. The helical railgun also offers some promise in that area, though it is not yet practical with real world technology, being a synthesis of railgun and coilgun technology.

(The problem of heating the projectile itself can be mitigated with a discarding sabot.)

Well, Mega particle cannons are said to be 4 times as efficient than lasers and Minovsky particles make it impossible to detect and hit something in those distances, so they don't need that long range any more to begin with.

All told, that suggests that the laser technology in the Universal Century's probably little more advanced than what we had when the series was first made. (This also has some rather unpleasant safety implications for shipboard laser systems, since the most efficient gain mediums available in a conventional weapons-grade laser system are unpleasantly toxic substances like fluoridated deuterium.)

Mind you, it's not that they didn't need that range anymore... it's that Minovsky particles made it impossible to shoot accurately at distances of more than a few tens of kilometers and conveniently degraded laser and guided missile systems to the point of uselessness. Minovsky particles conveniently made it so that Minovsky particles were the only viable weapon for "long" ranged space combat.

Thanks for the information on the RGM-79F Railguns. So if they were repurposed Naval Weapons does that mean the older Salamis or its predecessor was using railguns prior to the introduction of Mega Particle Cannons?

That does appear to be what the writeup is indicating, yes... though IIRC it's also said that the main offensive weapon of the pre-Minovsky particle EFF was guided missiles.