AutoPistol in a Vacuum...

[sabredog]

I've always figured that the higher tech rounds have an oxidizer in the propellant so they can be used in vacuum conditions. This also got around the trace, thin, and some exotic atmo questions. The rounds are either caseless and electrically primed, or traditional and have synthetic materials that are self lubricating. Very few moving parts and such. Factory sealed magazines with batteries built into them if the slugthrower needs juice.

Now the real issues that have come up leading to "Can I use my SMG here?" questions IMTU have been in exotic atmospheres with high concentrations of explosive or flammable gases. High hydrogen concentrations might make even the lowly body pistol an awesome looking thing when it fires.

 

[sabredog]

Yeah, I've seen that. No more hang-fires when shooting at that charging Grizzly.

I forget sometimes that "high tech" in Traveller means from the prospective of what people thought things would be like in the future while living in 1977.

I think the HK G11 was the highest tech gun produced back then and it was so gee-whiz because it had caseless ammo. But the Traveller model for an autorifle was just a BAR even though more advanced weaponry was coming off the lines or in development. A body pistol then might have been a PPK back then, but my real life body pistol is currently a baby Glock in .40SW....decidedly more than the original 2D6-4 or what ever it was.

 

[sabredog]

Well, in a lot of ways there is more visceral appeal in guns that make a lot of noise, smoke, and flame. It's not like the phasers in Star Trek or blasters in Star Wars were any more accurate - line o' sight and speed o' light not withstanding, than the bang-bang guns in Firefly or Aliens. But the latter were more fun. And meant the main characters could get shot up, too, without always getting disintigrated. I prefer that for my players, too.

Unless battledress is around, but even then an FGMP makes a big boom instead of a little crackle-zip-znap like lasers or railguns.

 

[Icosahedron]

I can't see that sucking the air out of an unsealed round will prevent it from firing, as the air isn't necessary. The oxidant is one of the chemicals in the powder. I see no reason why the ammunition would fail in vacuum. However, vacuum welding of the gun's moving parts might be a problem, and there will be additional details like the powder, wads, sabot cups, etc following the bullet all the way to the target, and dramatically increased ranges as there is nothing to slow the bullet down. And of course you don't need a silencer.

 

[atpollard]

In black powder, the oxidizer is saltpeter (potasium nitrate: KNO3) with three oxygen atoms waiting to react with the carbon and sulpher. Hence black powder rockets (Congreve Rocket @ TL 4) would also work in space.

Steampunk Traveller anyone?

 

[veltyen]

In black powder, the oxidizer is saltpeter (potasium nitrate: KNO3) with three oxygen atoms waiting to react with the carbon and sulpher. Hence black powder rockets (Congreve Rocket @ TL 4) would also work in space.

Steampunk Traveller anyone?

The TL4 vacuum asteroid colony. Diving bells, brass helmets, hand operated pumps, and good old basic TL3 and TL4 rocketry for propulsion.

Though where they'd get the nitrates from (oort cloud objects and similar maybe?) would be the big surprise.

 

[atpollard]

Same place they got in the days of old, shit and piss and some ash ...

I think this calls for a caste system ...

 

[Mark Morgan]

Real World Black Powder inline rifles can now have a electric primer. No more putting the cap on. Just load the powder, sabot (or bullet) and point, shoot. Good for several hundred shots on a 9volt battery.

Dave Chase

yes i know such a weapon could be built


has such a weapon been built offered for sale?

just curious since of things i know could be built that are n't

 

[atpollard]

has such a weapon been built offered for sale?

It was, but nobody bought it.

EtronX

 

[shadowdragon]

http://www.cva.com/rifles-electra.html

your link is broke

 

[Renaissance Man]

These days, my thoughts are that all TL10+ non-gauss firearms are hybrid-electro-thermal hydrogen gas guns, with hydrogen resevoirs in the clip and caseless rounds. The chamber is by definition sealed up, so vacuum or water shouldn't pose a problem.

 

[samuelvss]

I can't see that sucking the air out of an unsealed round will prevent it from firing, as the air isn't necessary. The oxidant is one of the chemicals in the powder. I see no reason why the ammunition would fail in vacuum.

You're absolutely right. (duh.... :nonono Wet powder is different than powder in a vacuum.

The other thing to think about is the effect of being at or close to absolute zero will have on on the metal itself and on the reaction. I know a change of 30 or 60 degrees F can have a significant effect on ballistics; about 400 F would have a greater effect.

One thing on range: sights zeroed for a gravity well would be way off if you got past point blank (about 250 m for a rifle).

If a TL4 revolver had been in space for a significant period of time (depending on sunlight, insulation, etc.) it is going to be close to absolute zero. I am not sure that whatever the chamber pressure (maybe 30-50% of what it would be at 65 deg F) caused by the ignition would not shatter the chamber (cylinder in this case).

http://www.newton.dep.anl.gov/askasci/eng99/eng99249.htm

I think the "high tech" would be as much a matter of metallurgy (ceramics or polymers?) as lubricants.

 

[Icosahedron]

Good points, Samuelvss, also differential shrinkage could seriously alter the fit of the bullet in the barrel even if neither shatters.

Hmm, makes you wonder if that Apollo handgun was worth taking. Maybe it was just intended to provide closure on board if something went very wrong...

 

[mike wightman]

Laser and optical sights become even better in zero g.

The smartware in the sight by TL9 should be able to compensate for local gravity

 

[veltyen]

Laser and optical sights become even better in zero g.

The smartware in the sight by TL9 should be able to compensate for local gravity

But only for weapons that would expect to be used in multiple different G's.

Marine weapons vs Army weapons. The army weapons could be recalibrated - the Marine weapons should auto-adjust.

 

[mike wightman]

At the risk of going off topic - a binary propellant slug thrower with proper smartware could adjust itself for what ambient conditions and the firers mode of choice.

Full auto spray close range work - reduce charge slightly for control etc.

 

[mike wightman]

But since the original topic is autopistols in a vauum - polymers and metallurgy answer the mechanical problems (by TL9+), while the chemistry behind firing the weapon is pretty basic.

 

[saundby]

I'll chime in here since I deal with these things in RL.

First, all gun propellants from any era work in vacuum. Slow match would work differently without air, it'd likely last longer. A lack of gravity to keep powder in the pan of a flintlock is the biggest problem I could see with any firearm type. Cap and ball would work fine. In free fall non cartridge firearms wouldn't have gravity to help with loading.

Space doesn't require exotic lubricants. Vacuum welding is a myth, events blamed on it early in Ranger and other such programs were actually insufficient lubrication, thermal binding, and so on.

Other effects aren't that bad, and unless you're looking at long cold soaks you don't need to worry about temperature. If you're going to be cold for a while, use no lubricant on the auto pistol.

20 degrees K would be a problem if you're submerged in cryo fluid or something like, but typically temp will be a problem for a suited user before the gun. If you light off a round in cryo fluid be prepared for plenty of gas expansion, the waste heats' going to put plenty of it through phase change. But the question was about vacuum.

The cold of space is a matter of radiation, not conduction or convection of the heat. So your gun won't stop working because you take it out the airlock. If you have a full auto firearm it'll not cool as efficiently than in the atmosphere if it relies on air cooling. So it'll overheat faster, and take longer to cool again.

Many polymers don't stand up well to space. Covering the polymer with some metal tape is an easy quick-fix. I doubt a Glock would have any problems with brief exposure, though. LDPE and MDPE is what I'm used to the problems being with, for the most part.

Anyway, your garden-variety firearm works fine in vacuum. If you're going to hang out there for some time, shoot the gun dry and deal with the wear or use a good low-temp non-petroleum grease. Silicon, TFE or graphite, perhaps.

I think I'd pick shooting dry on a gun with a steel slide and aluminum receiver by choice, but lots of commonly available things would work. You can get your grease at the bicycle shop when you're dirtside if there's no gun shop handy.

 

[Icosahedron]

I'll chime in here since I deal with these things in RL.

It's always good to talk to an expert.

First, all gun propellants from any era work in vacuum. Slow match would work differently without air, it'd likely last longer. A lack of gravity to keep powder in the pan of a flintlock is the biggest problem I could see with any firearm type. Cap and ball would work fine. In free fall non cartridge firearms wouldn't have gravity to help with loading.

Space doesn't require exotic lubricants. Vacuum welding is a myth, events blamed on it early in Ranger and other such programs were actually insufficient lubrication, thermal binding, and so on.

I like myth-busting. Got any references?

Other effects aren't that bad, and unless you're looking at long cold soaks you don't need to worry about temperature. If you're going to be cold for a while, use no lubricant on the auto pistol.

20 degrees K would be a problem if you're submerged in cryo fluid or something like, but typically temp will be a problem for a suited user before the gun. If you light off a round in cryo fluid be prepared for plenty of gas expansion, the waste heats' going to put plenty of it through phase change. But the question was about vacuum.

The cold of space is a matter of radiation, not conduction or convection of the heat. So your gun won't stop working because you take it out the airlock. If you have a full auto firearm it'll not cool as efficiently than in the atmosphere if it relies on air cooling. So it'll overheat faster, and take longer to cool again.

If the user's suit is heated, wouldn't that extend his endurance beyond that of the gun?

The gun won't stop working immediately on exposure to space, but its heat will radiate away over time and I imagine that's when expansion and brittleness problems will set in.

Many polymers don't stand up well to space. Covering the polymer with some metal tape is an easy quick-fix. I doubt a Glock would have any problems with brief exposure, though. LDPE and MDPE is what I'm used to the problems being with, for the most part.

Why do polymers have problems in space?

Anyway, your garden-variety firearm works fine in vacuum. If you're going to hang out there for some time, shoot the gun dry and deal with the wear or use a good low-temp non-petroleum grease. Silicon, TFE or graphite, perhaps.

I think I'd pick shooting dry on a gun with a steel slide and aluminum receiver by choice, but lots of commonly available things would work. You can get your grease at the bicycle shop when you're dirtside if there's no gun shop handy.

 

[samuelvss]

Assuming I have a TL7 (arguably TL5 ) M9 Berretta* . It's been in deep space for a week ("for a significant period of time"). (I'm assuming that's long enough to get down to about 20 K.) I fire it, without warming it up from about 20 K. Does the chamber shatter?

If I'm wearing a vacc suit, the blowing up process really doesn't hurt that much, it is silent and all, but it makes the first round close to ineffective and really reduces the percentage on the double tap.

Right out of the airlock, different story.

*Picked the Berretta because it is an autopistol, probably equivalent to what one might buy at TL7-8, and under ideal conditions has a mean slide failure rate of about 2,500 rounds. Not all autopistols are created equal.