Gauss Weapons... Questions

[Condottiere]

At some point between the assault and the advanced combat rifle, they've figured out caseless automatic fire without spontaneously combusting.

So you want to move that heat away from the magazine and the breach, so maybe a second exterior liner acting as a heat sink?

Semi automatic should, in theory, be doable; you could even have a paper cartridge that burns up.

 

[ottarrus]

At some point between the assault and the advanced combat rifle, they've figured out caseless automatic fire without spontaneously combusting.

So you want to move that heat away from the magazine and the breach, so maybe a second exterior liner acting as a heat sink?

Semi automatic should, in theory, be doable; you could even have a paper cartridge that burns up.

Not a bad handwave there. Certainly material technologies might solve the problems with caseless. I mean, if we can invent fictional materials to make fictional starship drives work ['zuchai crystals' for example] then working out heat transfer shouldn't be that big a problem.

 

[CordwainerFish]

Certainly material technologies might solve the problems with caseless. I mean, if we can invent fictional materials to make fictional starship drives work ['zuchai crystals' for example] then working out heat transfer shouldn't be that big a problem.

Mumble handwave materials science, mumble handwave more efficient coupling of chemical energy to kinetic energy. It's no sillier than TDX.

 

[Heartwarder]

Just one quick note: ammo for gauss weapons does not have to be ferromagnetic!

Just like modern day sabots, any kind of object can be propelled using a discarding ferromagnetic pad. While losing some efficiency, this allows to construct variant payloads munition, including armor piercing variants made from non-ferrous superdense materials. As an extra bonus, non-ferromagnetic projectile cant be deflected by electromagnetic shields - while we don't seem to have those used in official material, it seems like an easy thing to make using portable power sources that are available in the setting. Remember, you don't have to completely deflect a projectile for such things to be effective - as long as you negatively affect its stability, it will already lose a portion of penetration capability.

 

[Bill Sheil]

Just one quick note: ammo for gauss weapons does not have to be ferromagnetic!

Just like modern day sabots, any kind of object can be propelled using a discarding ferromagnetic pad. While losing some efficiency, this allows to construct variant payloads munition, including armor piercing variants made from non-ferrous superdense materials. As an extra bonus, non-ferromagnetic projectile cant be deflected by electromagnetic shields - while we don't seem to have those used in official material, it seems like an easy thing to make using portable power sources that are available in the setting. Remember, you don't have to completely deflect a projectile for such things to be effective - as long as you negatively affect its stability, it will already lose a portion of penetration capability.

If the ferro-magnetic component can be made the same diameter as the round it is propelling (to retain aerodynamics) then it would make more sense to retain it attached to the actual projectile itself. By definiton it is leaving the barrel at the same velocity as the bullet and its extra mass adds energy and momentum that reduces the relative drag effect so it gives longer range, accuracy and higher penetration and damage.

Discarding sabots (APDS) in chemical propelled weapon systems are bigger than the bullet because they are precisely designed to fill the gun barrel against the expanding gas of the cartridge while propelling a smaller diameter bullet ahead of them. The BAE/US Navy railgun utilised a shuttle that was also necessarily (due to technology) larger and bulkier that the aerodynamic requirements of the projectile and therefore also gets discarded. But in principal discarding mass that you have put energy into accelerating is a bad thing to do without a good reason in weapon design.

Also for gauss weapons it may also be disadvantagous to even have a closed barrel. When a bullet is driven down the barrel there is a counter force from the compression of the air in the barrel ahead of it and this may be more significant at higher velocities with long barrels, slowing the round down. In conventional weapons this is unavoidable (the barrel need to be sealed by the bullet or sabot) but there is no explicit need (depending on YTU) for a gauss projectile to fill the barrel when most of the force is being applied down the barrel. Apart from better performance an open barrel gauss weapon might also be quieter. This also raises the possibility that gauss weapons could (or should) be able to fire a wide variety of rounds of different radii down a wide barrel. Stabilising the rounds could be managed by shaping the magnetic field in the barrel so the round is released at one end and suspended in the cetre of the barrel radius during its traverse never needing a rail or barrel contact, or a spin could be added actually making it genuine gauss rifle. Even if there is no centering force applied a fin stabilised round that exits a 1m barrel at 1500m/s aftrer constant acceleration will only have free-fallen less than 0.01mm in the time is was inside the barrel.

Using magnetic fields to deflect gauss rounds is conceivable given that it is analogous to modern ERA (Explosive Reactive Armour) which uses chemical propelled explosive plates to directly counter chemical propelled kinetic projectiles but it would likely be the next tech level up in the arms race or several for personal level protection. It would probably have most of the limitations: it (MRA - Magnetic Reactive Armour) couldn't be a continuous field effect for practical use so it would have to detect and react with fixed aspect deflectors (because they could not be oriented in time) and it might be a degradable effect per deflector. or need a capacitor rechage time agains atatcks fromm the same dimension. Non-ferrous rounds would defeat it but in any case there is still ERA which might improve with technology enough to be an effective defense against any gauss weapons at a price.

 

[Condottiere]

1. Gauss systems don't need expanding gas to propel them, but maybe the closed barrel provides the magnetic field that does.

2. Considering the supposed hypersonic speed these projectiles are supposed to accelerate to, a magnetic deflection field would depend on strength and range to have an effect on the projectile.

3. This might work for installations and vehicles, but probably not for personal defence.

 

[ottarrus]

1. I can't see where Gauss systems would need expanding gas to propel anything. The whole point of using magnetic systems to fire projectiles is to avoid projecting anything with expanding gas.

2. The stronger the repulsion field, the less power is available for a vehicle's main functions. No vehicle is designed as a designated bullet magnet. They get used for that quite a lot, but that's not the principle design criteria. Cover and mobility will serve a vehicle much better than another wattage-soaking system.

3. I can't see magnetic shields at TL 15. Perhaps they might have some utility for an installation, but vehicles are currently designed with most of their power output directed at weapons. Furthermore, the addition of a magnetic shield is another source of electronic emissions that could theoretically be tracked by opponents. See a large magnetic signature in an area that might be tactically valuable but has no ferrous metals? That's a laager full of bad guys, so get the artillery on the phone.

4. And aren't repulsor screens up at TL 17? In the area of 'Yeah, I suppose that's possible but we don't even have the physics for that yet" territory.

 

[NOLATrav]

ISTR repulsors being TL13-15 in CT High Guard. But they were ship-based anti-missile installations.

 

[Bill Sheil]

1. I can't see where Gauss systems would need expanding gas to propel anything. The whole point of using magnetic systems to fire projectiles is to avoid projecting anything with expanding gas.

I am not sure why that's being discussed. My point was that the rationale for tight fitting barrels and discarding sabots in conventional weapons does not exist in gauss weapons precisely because they are not propelled by expanding gases. And a magnetic field can propel rounds down an open barrel with several mm gap between the projectile and the walls or magnets with a bit of loss of work between the magnets and the projectile but overall the energy requirement and recoil constraints are the same.

2. The stronger the repulsion field, the less power is available for a vehicle's main functions. No vehicle is designed as a designated bullet magnet. They get used for that quite a lot, but that's not the principle design criteria. Cover and mobility will serve a vehicle much better than another wattage-soaking system.

3. I can't see magnetic shields at TL 15. Perhaps they might have some utility for an installation, but vehicles are currently designed with most of their power output directed at weapons. Furthermore, the addition of a magnetic shield is another source of electronic emissions that could theoretically be tracked by opponents. See a large magnetic signature in an area that might be tactically valuable but has no ferrous metals? That's a laager full of bad guys, so get the artillery on the phone.

I have doubts about a magnetic deflection system anyway, partly because other technologies already exist and high-TL traveller armour materials may also be more cost effective defence, also because there may not be a static ferromagnetic element in the projectile, the round could be propelled by work on a inductive loop and some kind of handwavium superconductive system that could be simply disabled on leaving the barrel to avoid deflection in the planet's magnetic field.

In any case a "continuous-on magnetic field" system is non-starter which is why I cited ERA. To deflect an incoming round from any particular weapon you need to very fast, directed and concentrated energy of the same order of magnitude as that applied to the projectile in the weapon barrel. I have never been sold on the idea of a constant field repulsor system to be able deliver that work at anywhere near the same tech level as the weapon. But it is more conceivable (as with ERA) to have a fixed array of directed detectors-deflectors powered by electromagnetic charges or capacitors that only triggers in a fraction of a second before impact on detection of an incoming round at that aspect. It wouldn't take energy when it is idle but (for capacitors) only when recharging after it has been fired. But in any case I would not be convinced of its benefits over an upgraded ERA using traveller armour material plates and even a capacitive charge over the current chemical explosive implementation; as they could also deflect projectiles regardless of magnetic properties. An active hedgehog defence of mini sandcasters would also be worth considering.

 

[Condottiere]

1. Gauss system magnetic field versus internal combustion conventional ammunition.

2. As far as I know, tractor and repulsor beams are based on manipulation of tightly focussed gravity.

3. We have deflector screen at technological level ten, but they mitigate damage, so that tends to imply that they may slow down atoms or shockwaves, somehow, like Dune personal shields; more like partial deflection, like a sieve.

4. Tractor beam bays become available at technological level sixteen, and for some reason, the Imperium Navy eagerly embraces prototypes.

 

[Bill Sheil]

1. Gauss system magnetic field versus internal combustion conventional ammunition.

... and... ?

2. As far as I know, tractor and repulsor beams are based on manipulation of tightly focussed gravity.

3. We have deflector screen at technological level ten, but they mitigate damage, so that tends to imply that they may slow down atoms or shockwaves, somehow, like Dune personal shields; more like partial deflection, like a sieve.

4. Tractor beam bays become available at technological level sixteen, and for some reason, the Imperium Navy eagerly embraces prototypes.

Classic traveller tractor/repulsors were intended to deflect missiles in space therefore with a lot of time (relatively) to aim and apply a deflective force. At the time spaceborne mass drivers and railguns were not part of the canon. It is likely to have been retconned by someone to include deflecting gauss weapons and mass drivers projectiles but in truth deflecting high velocity kinetic rounds would be expected to be an order of magnitude more difficult than redirecting missiles.

 

[Condottiere]

1. You either have one or the other, having both probably gets in each other's way.

2. I can't recall when repulsor or tractor beams were invented in science fiction, though Sector General mentions them, and they were installed on the Enterprise.

3. It has to be an area, if rather narrow, effect; for a large object, only one object would be effected, or for a bunch of bullets coming from the same gun, or maybe from a close clustered squad.

4. Deflection probably would be a curved area of effect, that doesn't stop bullet, but encourages them to travel along the line of least resistance.

5. Deflection in terms of a guided missile would require the repulsor beam to grip it until it either guides it away from the original target, or shakes up the components so it effectively mission kills the missile.

6. A magnetic repulsion field is unlikely to be effective against gauss propelled missiles.

7. A repulsor beam, on the other hand, should be effective.

8. A deflector screen, who knows? It depends on how it works, if it robs a gauss bullet of velocity, which wouldn't matter if the warhead is basically high explosive.

 

[Heartwarder]

What exactly is a magnet "emitting" in your minds, that can make a combat vehicle or mechanized suit more easily detectable?
But I digress, arguing about feasibility of technical applications in soft sci-fi settings is not worth the time.

Bottom line, Guass weapons described in canon - i.e. high velocity - will make sound in atmosphere comparable to suppressed assault rifles from projectile alone. How much sounds machinery inside the gun makes is an open question, likely not that much. It is conceivable for a magnetic accelerator to propel heavy projectile slowly - aka magnetic .45 ACP equivalent for silent weapon, but it would hit with the same strength as that. Ammo would be more compact due to lack of casings, but if a power source eats up the difference back depends on "future technology".

 

[Bill Sheil]

1. You either have one or the other, having both probably gets in each other's way.

I am still confused about the point you are making. Who is mixing gauss technology and expanding gas (chemical propelled) rounds, if that is what you mean?

My earlier statment regaring sabots was about two distinct cases, first CPRs:

Discarding sabots (APDS) in chemical propelled weapon systems are bigger than the bullet because they are precisely designed to fill the gun barrel against the expanding gas of the cartridge while propelling a smaller diameter bullet ahead of them.

and seperately rail guns:

The BAE/US Navy railgun utilised a shuttle that was also necessarily (due to technology) larger and bulkier that the aerodynamic requirements of the projectile and therefore also gets discarded. But in principal discarding mass that you have put energy into accelerating is a bad thing to do without a good reason in weapon design.

 

[Condottiere]

1. Gauss sidearms as listed in the current edition have clearly magnetically accelerated ammunition.

2. Whether there is a buffer occupied by the magnetic field between the walls of the barrel and the slug, I wouldn't know.

3. If there isn't, the barrel itself could be emitting the magnetic field.

4. There might be some form of square law in relation to calibre size of the slug, and the energy required to accelerate it.

5. In which case, you'd want to find a size effective enough for combat, and small enough for optimal use of space (magazine) and the storage battery (propulsion).

6. If you wanted to minimize recoil, if any, you could make the slug rocket propelled.

 

[Condottiere]

1. One thing a magnetic field would certainly supercede internal combustion, would be that it could impart spin and still be smoothbore, so that would take care of barrel wear and tear.

2. Might also be one reason you wouldn't need to sabot the ammunition.

3. I assume barrel length would still be relevant to range and accuracy.

4. And muzzle velocity.

5. It's an interesting consideration if you could substitute the four millimetre slug with a bunch of pellets, to act like a shotgun shell.

6. Since pellets would be a tad over four millimetres, you'd shrink them and line them up like ducks in a row.

7. Iron might work, though could also be stainless steel.