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Anthony G Williams
Greybeard
      
Date Joined Apr 2007
Total Posts : 397
| Posted 3/28/2008 10:25 AM (GMT -4) |   | | Guns don't need air: the oxygen needed for combustion is an integral part of the propellant contained within the cartridge case.
Recoil would be the same, but it might have more noticeable effects, because the weaker gravity wouldn't do such a good job of holding you down.
Some other effects:
- the lack of atmosphere would mean that the bullet wouldn't slow down due to air drag, so it would be travelling at muzzle velocity throughout its flight, and would hit the target with greater force. And the trajectory wouldn't be affected by cross-winds.
- the lighter gravity on the Moon would mean a much flatter trajectory as the bullet would fall towards the ground at only one-sixth the rate. Combined with the high velocity, it means that the effective range would be much greater. However, holding the gun steady enough to hit a target at long range would be just as difficult.
- the great variation in ambient temperatures would have two effects: the projectile ballistics would vary, because the chamber pressure developed in the gun is affected by propellant temperature; and in extreme cold the mechanism of the gun could seize up, with metal parts being cold-welded together. In fact, keeping an automatic weapon going could be quite difficult because any lubricant could freeze, so some means of keeping it warm would probably be needed.
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tchernabyelo
Acolyte
Date Joined Oct 2006
Total Posts : 416
| Posted 3/28/2008 10:28 AM (GMT -4) | | Recoil itself will be exactly the same as it's a function of mass(not weight)/velocity.
IIRC, most propellant explosives contain their own oxidant and don't require air (guns can fire underwater, but the bullets are hugely slowed down by the density of the medium - a 9mm lethal range is a few feet at most). It is risky though - any air in the barrel could make the gun explode, and the mechanism is unliely to let you get more than one shot off. In a vacuum these problems wouldn't be an issue so I suspect "normal" guns would work just fine.
Ballistics is a wonderful thing in vacuum, since there's no drag to slow the bullet, pure vector calculations will work, so artillery would be much more accurate.
ETA - was clearly simultyping with Tony! His point about gravity on recoil is fair, i.e., things are less "anchored down", but the actual force being applied should by my reckoning be exactly the same as on Earth (or on Jupiter). Hadn't considered the temperature issues.
Brian Dolton
Yi Qin stories:
"The Box Of Beautiful Things" - IGMS#3
"The Man Who Was Never Afraid" - Abyss and Apex #20
"At Blue Crane Falls" - Abyss and Apex #25 "Where No Wind Blows" - Staffs & Starships #2
"What The Sea Refuses" - Black Gate (forthcoming)
"What The Heart Bears" - Black Gate (forthcoming)
"Above The Clouds" - Paper Blossoms, Sharpened Steel (forthcoming)
Other Land Of Wind And Ghosts stories:
"The Dragon Path" - Fictitious Force (forthcoming)
"Three Out Of Four" - Sorcerous Signals Feb-Apr 08
Stories in other settings:
"The Unicorn Hunter" - OG's Speculative Fiction #8
"Call Centre" - Necrotic Tissue #1
"When Winter Came" - ASIM #32
"Cold Fire" - Flashing Swords #9
"St. Saviour And The Devil's Dandy" - Flashing Swords (forthcoming) | | Back to Top | | |
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FredLand
Stablehand
Date Joined Mar 2008
Total Posts : 19
| Posted 3/28/2008 12:03 PM (GMT -4) | | Anthony, I think holding the gun steady in one sixth gravity would me more difficult do to the lack of barrel weight. Steadiness generally depends on the downward 'pull' of the muzzle.
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FredLand
Stablehand
Date Joined Mar 2008
Total Posts : 19
| Posted 3/28/2008 12:20 PM (GMT -4) | | Okay, I concur.
I hate it when I'm wrong. :)
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Gustavo
Sage
Date Joined Aug 2007
Total Posts : 1149
| Posted 3/28/2008 10:50 PM (GMT -4) | | | | |
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