Which weapons would function in void?

By Cheddah, in Rogue Trader Rules Questions

Since void suits are an option, and who knows what kind of crusty space barnacle baddies are out there in the stars?

I'm assuming that anything that SP, Launcher, Bolt weapons might need oxygen to work. The others seem to work out their firing mechanism in sealed chambers with various gases, and should work just fine.

Technically you fire pistols underwater and 2 pistols is one of the things an astronaut would take along when stranded on the moon so yes...they work, theough they might be less accurate.

Depends on the fuel used. Some fuels are self-oxidising, meaning they don't require an external source of oxygen. This is mainly done because they can't get the oxygen from the air fast enough to work. I think this includes some bullets. However there would be problems with the guns lubrication boiling off in a vacuum, or the weapon overheating because it can conduct heat into the surrounding atmosphere.

The inquisitors handbook (page 165) has void rounds for all SP weapons, which are designed for use in 'void conditions' and make any weapon using them reliable.

Cheddah said:

Since void suits are an option, and who knows what kind of crusty space barnacle baddies are out there in the stars?

I'm assuming that anything that SP, Launcher, Bolt weapons might need oxygen to work. The others seem to work out their firing mechanism in sealed chambers with various gases, and should work just fine.

SP weapons tend to need specialized void rounds, otherwise the weapon will become unreliable. Bolt weapons on the other hand should work just fine (miniature rockets for ammo).

Cheddah said:

I'm assuming that anything that SP, Launcher, Bolt weapons might need oxygen to work. The others seem to work out their firing mechanism in sealed chambers with various gases, and should work just fine.

As Bilateralrope pointed out, there are indeed Void Rounds for solid projectile weapons... Grenade launchers are described as using a charge of compressed air to fire their rounds, so I can't see there being an issue to using them in vacuum. Missile and bolt round propellants would probably be the self-oxidizing type.

-=Brother Praetus=-

Most weapons should function perfectly well in a vacuum, there are ways of modifying every type of weapon in the armoury to make it work in such conditions- many will need no modification at all.

Personally, I'd just assume they all work with no modification needed. I don't really see anyone buying the versions of a weapon that have problems in a vacuum for issue to a Starship's crew.

I would agree with most posters. All weapons should work, although SP weapons not using void rounds gain Unreliable while in a void (increased chance of misfire).

dvang said:

I would agree with most posters. All weapons should work

I would argue that your typical Imperial Flame Weapons are not going to function in a vacuum without extenisve modifications and specialized fuel.

The only way a flammer would would work is if the fuel was self-oxidizing. So you'd likely need special ammo.

Dalnor Surloc said:

The only way a flammer would would work is if the fuel was self-oxidizing. So you'd likely need special ammo.

This is what lexicanum has to say about promethium:

Promethium is a general term for any form of fuel in the Imperium.

The term also commonly refers to the substance used as fuel for Imperial flamer weapons, a highly volatile incendiary gel which immediately ignites on contact with oxygen. It reaches super hot temperatures. Similar to napalm, the gel sticks to an individual, continuing to burn on its own accord, even underwater.

Of course, since the first part says "general term for any form of fuel in the Imperium", it could mean simple gasoline or even certain alcoholic beverages. But the other part says that it immediately ignites on contact with oxygen, which seems to imply that it is in fact self oxidizing, it just needs oxygen to trigger a necessary chemical reaction to ignite.

So according to the latter description, all you'd really need for a flamer to work in vaccum is a little oxygen dispenser near the nozzle of the flamer. With the trigger pulled, a spray of oxygen is dispensed and the promethium comes into contact with it and voila! You have a void fire!

But the other part says that it immediately ignites on contact with oxygen, which seems to imply that it is in fact self oxidizing, it just needs oxygen to trigger a necessary chemical reaction to ignite.

If contact with oxygen is all it takes to set it off and it's self oxidizing, chances are the fuel is going to burn really fast because the flame from oxygen contact must be hot enough to set the rest off.. Probably too fast to be useful as a flamer. Even worse, it sounds like it will burn faster than it comes out of the flamer, leading to the fuel inside the tank burning causing an overheat and/or explosion. A tiny* hole in the tank, or getting the tank hit by another flamer, is going to set off a nasty chain reaction.

*Big enough to let oxygen in but too small to see.

But if the fuel isn't self oxidising, that makes things much safer because even if the fuel inside the tank gets heated enough to ignite, there isn't any oxygen for it to burn with. And if the tank does get a small hole, that hole would limit how fast oxygen got it. Being hit by another flamer won't cause a failure in your one unless the other flamer manages to melt your fuel tank.

So if you want a sane flamer that works in a vacuum, you have one option - The fuel ignites on contact with oxygen, but isn't self oxidising. Instead you also have a tank of liquid oxygen and you mix them after they leave the flamer.

Then again, wanting a flamerthower to work in a vacuum isn't exactly a sane idea to start with.

Bilateralrope said:

But the other part says that it immediately ignites on contact with oxygen, which seems to imply that it is in fact self oxidizing, it just needs oxygen to trigger a necessary chemical reaction to ignite.

If contact with oxygen is all it takes to set it off and it's self oxidizing, chances are the fuel is going to burn really fast because the flame from oxygen contact must be hot enough to set the rest off.. Probably too fast to be useful as a flamer. Even worse, it sounds like it will burn faster than it comes out of the flamer, leading to the fuel inside the tank burning causing an overheat and/or explosion. A tiny* hole in the tank, or getting the tank hit by another flamer, is going to set off a nasty chain reaction.

*Big enough to let oxygen in but too small to see.

But if the fuel isn't self oxidising, that makes things much safer because even if the fuel inside the tank gets heated enough to ignite, there isn't any oxygen for it to burn with. And if the tank does get a small hole, that hole would limit how fast oxygen got it. Being hit by another flamer won't cause a failure in your one unless the other flamer manages to melt your fuel tank.

So if you want a sane flamer that works in a vacuum, you have one option - The fuel ignites on contact with oxygen, but isn't self oxidising. Instead you also have a tank of liquid oxygen and you mix them after they leave the flamer.

Then again, wanting a flamerthower to work in a vacuum isn't exactly a sane idea to start with.

Well to be fair I find the idea of promethium to be a little less than sane to begin with.

I mean in one sentence they describe it as a "catch all term for fuel" which could pretty much mean anything that will burn, but in the next they ascribe properties to it like it was just one single chemical.

It's confusing and contradictorial to say the least.

But about your comment on the flamer tank chain reaction. Remember that WH40K is largely governed by the rule of cool, and if we are to believe hollywood movies, then having fuel tanks for flamethrowers explode as soon as they are ruptured by bullets is REALLY, REALLY COOL! (despite of the fact that the fuel of a real world flamethrower would simply seep out of the hole in the tank rather than igniting), then we can safely assume that explosive chain reactions is not a bad thing in 40K, don't you agree? lengua.gif

Varnias Tybalt said:

Dalnor Surloc said:

The only way a flammer would would work is if the fuel was self-oxidizing. So you'd likely need special ammo.

This is what lexicanum has to say about promethium:

Promethium is a general term for any form of fuel in the Imperium.

The term also commonly refers to the substance used as fuel for Imperial flamer weapons, a highly volatile incendiary gel which immediately ignites on contact with oxygen. It reaches super hot temperatures. Similar to napalm, the gel sticks to an individual, continuing to burn on its own accord, even underwater.

Of course, since the first part says "general term for any form of fuel in the Imperium", it could mean simple gasoline or even certain alcoholic beverages. But the other part says that it immediately ignites on contact with oxygen, which seems to imply that it is in fact self oxidizing, it just needs oxygen to trigger a necessary chemical reaction to ignite.

So according to the latter description, all you'd really need for a flamer to work in vaccum is a little oxygen dispenser near the nozzle of the flamer. With the trigger pulled, a spray of oxygen is dispensed and the promethium comes into contact with it and voila! You have a void fire!

While normally stuff in the Lexicanum is pretty much 40k Gospel, this is not. There are many instances of "spilled" Promethium, raw, unprocessed Promethium bubbling up from pools in the ground etc. occuring in official fluff sources. So Promethium tends to exhibit all the traits of petroleum.

Refined Promethium, on the other hand, exhibits all the properties of gasoline. I have even heard "jellied" Promethium mentioned, which exhibited all the qualities of Napalm. I've read that Rhinos engines were designed to use whatever form of unprocessed raw Promethium was local, but the Rhinos Machine Spirit didn't like it and didn't perform as well.

In the Gaunt's novels, normally the flamer guy would have Refined Promethium in his tanks, but raw Promethium did just fine on several occasions and on one occasion he got to blow up a huge pool of the stuff that was naturally occurring in the ground.

I'm not saying a flamer wouldn't work in the Void. I'm saying it's most realistic that it have to be refitted with an O2 dispenser in place of the normal Pilot Light, and the tanks be filled with oxygenated Promethium. Not a big deal for a rich RT, just that the players would have to specifically state that they have X number of these for this specific purpose...not just 'assume' they do or that normal, unmodified flamers will work in a vacuum.

That's my 2 cents. You dan do whatever you want, it's your game after all!

I agree with SP weapons becoming unreliable and flamers not functioning in a void without modification. It's a GM judgement call, though standard Imperial gear would all be designed with oxygen-rich atmosphere in mind, since any other environment requires specialized equipment and training to survive in, much less fight in. If it's cheaper to mass-produce in the quadrillions, rounds may require oxygen since 99.99%+ of their intended usage will be in a normal breathable atmosphere.

I'm reminded of the episode of Firefly in which Jayne's gun, Vera, has a space suit rigged up around it so he can take a shot outside the ship.

If you wanted to be really mean, las weapons without additional cooling equipment could gain the Overheats quality, since the only way for them to dump heat is through the person holding it no air to suck up waste heat.

Pandadan said:

It's a GM judgement call, though standard Imperial gear would all be designed with oxygen-rich atmosphere in mind

Uhm, Im not sure about that. Remember that we're talking about the same Imperium whose "standard" sets of power armour have integrated rebreathers and are in fact very capable of keeping it's operator fully functuioning in void enviroments as long as the user doesn't take of his or her helmet.

Also, lasguns (which is one of the most standardized weapons in the Imperium) would be pretty useless from a military standpoint in case the troopers are sent to fight a war on a planet that doesn't have a very oxygen-rich atmosphere.

Just sayin'

Varnias Tybalt said:

Pandadan said:

It's a GM judgement call, though standard Imperial gear would all be designed with oxygen-rich atmosphere in mind

Uhm, Im not sure about that. Remember that we're talking about the same Imperium whose "standard" sets of power armour have integrated rebreathers and are in fact very capable of keeping it's operator fully functuioning in void enviroments as long as the user doesn't take of his or her helmet.

Also, lasguns (which is one of the most standardized weapons in the Imperium) would be pretty useless from a military standpoint in case the troopers are sent to fight a war on a planet that doesn't have a very oxygen-rich atmosphere.

Just sayin'

"Standard" power armor certainly isn't standard-issue, though; it's specialized gear with all the bells and whistles reserved for elite troops or VIPs. I would imagine that there are Imperial Guard regiments specifically trained and equipped for combat in non-habitable environments and/or the void, but they're not the norm. Most aliens seem to all breathe oxygen in WH40k anyway, so that's mostly a non-issue; the vast majority of worlds anyone wants have breathable (if polluted) air, and most personal combat in space takes place inside ships.

Of course, if the standard STC lasgun is designed to work in a void, they all will, so it's easy enough to hand-wave away. Just a reasonable complication to toss in if needed.

In terms of Flame weapons; on a whim my group decided that good quality flame weapons work in a vacuum while normal quality ones do not.

We decided this because A) it made the good quality matter since B) it let the missionary do something during the space adventure.

The natural extention of this was that Best quality flame weapons work underwater, of course.

monkyman said:

In terms of Flame weapons; on a whim my group decided that good quality flame weapons work in a vacuum while normal quality ones do not.

We decided this because A) it made the good quality matter since B) it let the missionary do something during the space adventure.

The natural extention of this was that Best quality flame weapons work underwater, of course.

Reliable still works for flamers. First you roll the d10 for damage, if that's a 9 then reliable kicks in and makes you roll another d10.

Or are you saying that reducing the jamming chance from 10% to 1% doesn't matter ?

Here is how I plan to treat various weapons in a vacuum:

Las weapons: In a vacuum there are cooling problems using higher powered shots:
- Weapons using hotshots gain the overheat quality.
- Overcharged las weapons gain overheat when firing in semi or full automatic. If fired in single shot there is no effect because the weapon can cool between shots.
- If it uses regular ammo without an overcharge pack, there is no effect.

SP weapons are assumed to use self-oxidising charges to propel the bullet so they still work. However the weapons lubricants will boil off, meaning that the weapon will lose become unreliable and stay that way until the lubrication is replaced. Using void rounds will negate this as they re-lubricate the weapon with each shot fired.

Bolt weapons get the same treatment as SP, but they don't get void rounds.

Meltas gain the overheat quality.

Plasma weapons suffer -1 to their blast radius as the plasma disperses faster. If they are fired without the blast quality there is no effect.

Flame weapons won't work because they can't get the required oxygen from the air. But if one of my players comes up with an idea of how to modify it (like the ideas here) then I'll accept it. Though without the ability to set someone on fire* , don't flamers lose a lot of effectiveness ?
*There is no way I'll be treating flesh or clothing as self oxidising.

Primitive weapons work without any issue, except flintlocks and muskets which simply won't work.

Launchers: Same lubrication problem as bolters, along with ammo-specific problems.

Grenades:
- Smoke and blind grenades disperse much faster due to the lack of air.
- Anti-Plant, hallucinogen and virus grenades fail because everyone is in a sealed suit.
- The rest have no problems.

Exotic: Still thinking about them.

Melee weapons: They should all work without trouble, except chain weapons which I'm unsure about.

normal gunpowders are self-oxidizing; they wouldn't detonate if they didn't. Since SP weapons seem to be using detonating propellants, they should work just fine in vacuum. The weapon itself is going to have issues with volatilizing of lubricants in vacuum. Should fire, should jam more often. Also lack of convection means heat issues.

Boltguns, same basic issues. Less mechanical wear, but still the same issues.

Flamers: with the right fuel, no problem. Binary CStof/TStof works quite well so long as you don't get hit... But it also rapidly volatilizes. I'd cut range and damage in half, and add overheat.

Lasguns: Heating issues only. Even more accurate than in atmosphere.