9mm VS 45ACP for Shooting in Outer Space?

[romma]

What caliber for Black hole?

 

[Gun Slinger]

Being the math and physics 'nut' that I am, I couldn't help but run a few numbers through the momentum (ρ) equation:

ρ = mv and mv = mv

For both the .45 A.C.P. and the 9mm.

Assuming that the pistol remains operable in the frigid vacuum of space and assuming a man (properly attired for the vacuum of space, of course!) who weighs 200 pounds (1.4 million gr.) (including his spacesuit, pistol and ammunition), assuming that he and the pistol are free to recoil as a combined unitary mass and assuming that there is a 'negligible' effect from the propellant gases exitting the muzzle of the pistol...

...if he fires a .45 A.C.P. 230 gr. bullet at 825 f.p.s. his resultant rearward velocity will be:

(230 gr. x 9,900 in./sec) ÷ (1,400,000 gr.) =

1.626 in./sec. or .0924 mph

or...

...if he fires a 9mm 115 gr. bullet at 1155 f.p.s. his resultant rearward velocity will be:

(115 gr. x 13,860 in./sec.) ÷ (1,400,000 gr.) =

1.139 in./sec. or .0647 mph

...neither of which is particularly fast, but still quite enough to become a bit "problematic" if our astronaut friend does nothing to correct this if he is not already not tethered to his spaceship.

Left unresolved, even at the slowest recoil velocity of just 1.139 in./sec. (9mm) within five minutes he will be about 28.5 feet away from where he fired his pistol and will continue to drift at this rate 'in perpetuity' unless he fires another shot in exactly the opposite direction to stop himself. He would then need to fire another shot in the same direction once more to get back to the point where he started (spaceship?).

I suppose that such an unforgiving environment would definitely be the place to have a spare 'high capacity' magazine or two available since running out of ammunition even if you managed to perforate and eliminate your opponent could still be the death of you if you are left in the unenviable condition of drifting away after a long string of fire.

ETA:

Perhaps the 'solution' would be a .25 Auto firing a 50 gr. bullet at 750 fps.:

(50 gr. x 9000 in./sec.) ÷ (1,400,000 gr.)=

0.321428 in./sec. or about .018262 mph

However, if you waited for just one minute before doing anything to stop your rearward travel you would find that you will have moved about 19.25 inches (a little more than a foot and a half) away from where you fired the gun to begin with so you could still find yourself in a bad way depending on your circumstances.

 

[-v-]

Also remember, space-time folds back on itself, so the bullet you fire in any direction will, after billions if not trillions of years come back and strike you in your hypothetical back. Best to shoot at the earth, that way the bullets burn up in the atmosphere!

 

[Gun Slinger]

-v-,

Best to shoot at the earth, that way the bullets burn up in the atmosphere!

"Real" tracers!

 

[Elm Creek Smith]

"Needlers" were used in The Childe Cycle novels of Gordon Dixon about the Dorsai. I don't know if they were used there first though. There was a novel or short story meant for youngsters years ago where the protagonist, a space fighter pilot, used his pistol to maneuver when he had to "bail out" of his craft. I think he used it to reach a nearby ship, but it was many moons ago when I was...younger, a lot younger.

ECS

 

[Blackbeard]

We're overlooking the fact that all motion in space is relative. Firing a bullet at 1200 fps is only effective if your target has the same velocity vector that you do. It doesn't do much good to fire something 1200 fps away from you if your target is already moving at 13,000 fps away from you. If he's moving at 1200 fps toward you, just eject a cartridge and toss it by hand into his path. He's deader than corduroy.

 

[PaStEuRiZeD]

You could shoot black powder in space as contains potassium nitrate which would supply oxygen to the reaction.

 

[KelVarnson]

I like threads that make me laugh out loud by just reading the title.

 

[Gun Slinger]

Originally posted by Blackbeard:
If he's moving at 1200 fps toward you, just eject a cartridge and toss it by hand into his path. He's deader than corduroy.

Actually, you'd still be better off shooting at him since you'd be effectively doubling the 'relative' velocity of your round as opposed to his body's vector if it were the 9mm 115 gr. bullet moving at 1155 f.p.s. as posted above and it would then give your bullet four times!!! the kinetic energy versus just placing the whole thing (at 0 fps) in his path.

Imagine that! A 9mm with 1416 foot-pounds of kinetic energy.... that's some 9mm!

 

[Tom Fury]

Firefly again:
In the "Our Mrs. Reynolds" ep They needed Jayne to be able to fire Vera from the open cargo bay in open space. To do this, they put it in a suit. The writers later discovered this would not have been necessary, though I have always wondered; atmospherics aside, wouldn't a conventional (moving parts) firearm freeze?
cheers, TF

 

[Gun Slinger]

Tom,

I would suspect that you'd need a lubricant that would not solidify at the low temperatures encountered and 'tie up the works' while still being heat resistant enough to withstand the heat generated by full on exposure to the sun's heating.
Of course, there would also be the issue of metal embrittlement and fracturing at the low temperatures to be expected, too.

Oh yeah, it'd also need to not evaporate under the near perfect vacuum of space, too.

 

[brickeyee]

Space is mostly empty, and heat needs something to carry it away.

It’s called radiation, as in infrared. An electromagnetic wave like light, radio waves, etc.
All you need is surface area and a temperature difference.
And in classical thermodynamic terms, space is VERY cold.

I would suspect that you'd need a lubricant that would not solidify at the low temperatures encountered and 'tie up the works' while still being heat resistant enough to withstand the heat generated by full on exposure to the sun's heating.
Of course, there would also be the issue of metal embrittlement and fracturing at the low temperatures to be expected, too.

You do know we have all sorts of things in space that move, right?
Steerable antennas, steerable solar panels, rotating parts, etc.

Embrittlement is only a problem for certain specific materials.
What do you think satellites are made from?

Hint: Aluminum is very popular.
It takes a lot of energy and $$ to get mass into earth orbit.

 

[Gun Slinger]

Originally posted by brickeyee:
You do know we have all sorts of things in space that move, right?.....

What do you think satellites are made from?

brickeyee,

Yeah, I know.

I also know the difference between convective and radiant thermal processes.

I am not stupid.

Quite frankly, I could do without the condescension.

 

[Carl N. Brown]

I know that the DVD commentary on "Firefly" - episode "Our Mrs. Reynolds" - does mention the screenwriters misunderstood what the firearms consultant told them about the Callahan Full-Bore Autolock (not) needing oxygen to fire. (Geez all they had to do was read the manual.)

But that made me think about how we kids used to get a little "omph" from our Daisy air rifles by "dieseling" using a little oil in the compressed air chamber. At least we got our air rifles to smoke like real guns.

If "Vera" drew oxygen from atmo to fire, the powder charge could be 100% fuel, rather than the usual 75% oxidiser and 25% fuel (think fuel-air mix). Meaning a cartridge the size of a .44 mag could be the equivalent of a .50 BMG.

By the way, a flintlock would fire in space.

 

[nicholst55]

I'll stick to my phase pistol, personally.

 

[madmike]

The first thing that comes to mind in this thread is the DISGRACEFUL state of American public schools.

To graduate, I needed a lousy ONE unit of science and math, THREE of English, that mostly stressed how to write a stupid "vitae" (something I have never needed in my life), ONE of phys ed, ONE of a foreign language, ONE of social studies...

Do your kids a favor: Make them take three units each of math and science. Liberal (and extreme conservative) anti-logic doesn't work on people who have learned how to think rationally.

As to science, I've seen too many threads on firearms with crap to the effect of, "That's just some guy in a lab (with decades of education, reams of data, millions of dollars worth of equipment, notes, photos, calculations and tests). I think I'm going to have to side with 'the man in the field' (who is possibly illiterate, probably not trained in analysis, stressed out, biased and operating in an uncontrolled environment).

This is called the Dunning-Kruger effect:

http://www.apa.org/journals/features/psp7761121.pdf

As to the science in question here:

The recoil will only move the person as a function of their mass relative to the bullet, i.e.: Very little.

The recoil is instantaneous enough and sufficient that a typical recoil-operated action should still function.

Vacuum-safe lubricants include PTFE (Teflon) and buckyballs.

While for thermogodammic purposes, space is cold, vacuum still functions as an insulator. Heat loss or gain is through conduction or radiation only. Sustained fire will require cooling vanes or flutes. An enclosed holster should prevent excessive cooling. A small heat source could be added if needed.

While without atmospheric disturbance a bullet will fly straight, it is still subject to deflection from muzzle blast, and unequal force. Rifling would still be a good idea.

The projectile will eventually slow down from impact with dust and gas particles, which do exist in space, just in lesser amounts. There is also GRAVITY from every chunk of rock and THE SUN, plus planets. Those bullets will stay in Earth/solar orbit and will decay and crash eventually.

And everyone knows the .45 ACP will be firing volleys in salute when the last 9mm is buried.

 

[brickeyee]

brickeyee,

Yeah, I know.

I also know the difference between convective and radiant thermal processes.

Is that quote even yours?

You obviously don't know very much about space and spacecraft if you are worrying about embrittlement.

Every satellite generate heat from the payload and/or additional heaters to keep the electronics operating.

Typical box operating temperatures are around room temp on earth. We design them that way.

Radiative cooling (with a circulating liquid) is used if power is so high that it could result in overheating.

 

[theotherwaldo]

In my mis-spent youth I was hooked up with the guys that parked a booster stage, tiled in material samples, in orbit for something over three years, then got it back down intact. Yeah, it was only supposed to be for three months, but something went worng... I mean wrong.
There were a few surprises, just as there will be when firearms are taken into space.
For example, most cartridges are full of air pressurized at roughly 32psi. Is that likely to cause primers or projectiles to pop out under vacuum conditions? Might they decompress and allow the propellants to outgass and decompose?
Will the springs and small parts overheat, harden, and turn brittle?

So many questions!

-and settle down, madmike, or I'll start psychoanalyzing your heroic elf.

 

[madmike]

-and settle down, madmike, or I'll start psychoanalyzing your heroic elf.

Oh, please do I've always said I can't wait for someone to write a thesis about my work so I know what I meant when I wrote it

 

[k_dawg]

FN5.7 with the armor piercing rounds would be my choice [ out of regular handguns ].

High capacity, and can punch thru most anything.

 

[Gun Slinger]

Is that quote even yours?

Yes. If you can't keep track of to whom as well as what you are responding to then perhaps you'd be best to curb your condescending attitude not to mention your posts. Certainly not very "high road" of you.

You obviously don't know very much about space and spacecraft if you are worrying about embrittlement.

I never claimed to, since I was speaking as a 'layperson'.

However, it is clear that both your reading comprehension as well as your manners could stand some improvement. Good luck with that colossal task.

 

[benEzra]

(According to internet-urban-legend-lore, teflon was actually invented for the space program, don't know if that's true.)

Not true, though it was used to great benefit there. Its first large-scale use was the Manhattan project, actually (because it could stand up to uranium hexafluoride).

From Wikipedia:

History

PTFE (Teflon) was invented accidentally by Roy Plunkett of Kinetic Chemicals[1] in 1938.[2] While Plunkett was attempting to make a new CFC refrigerant, the perfluorethylene polymerized in its pressurized storage container. (In this original chemical reaction, iron from the inside of the container acted as a catalyst.) Kinetic Chemicals patented it in 1941 and registered the Teflon trademark in 1944.[3] The original patent number is US2,230,654.[4]

Teflon was first sold commercially in 1946. By 1950, DuPont had acquired full interest in Kinetic Chemicals and was producing over a million pounds (450 t) per year in Parkersburg, West Virginia. In 1954, French engineer Marc Grégoire created the first pan coated with Teflon non-stick resin under the brandname of Tefal after his wife urged him to try the material, that he'd been using on fishing tackle, on her cooking pans.[5] In the United States, Kansas City, Missouri resident Marion A. Trozzolo, who had been using the substance on scientific utensils, marketed the first frying pan, "The Happy Pan," in 1961.[6]

An early advanced use was in the Manhattan Project as a material to coat valves and seals in the pipes holding highly reactive uranium hexafluoride in the vast uranium enrichment plant at Oak Ridge, Tennessee, when it was known as K416.

 

[MAURICE]

I have heard that the US antronauts actually have 45s on the spacecraft as part of an emergency propulsion system (just to move there person around space)

As a former High School science nerd, I heard this as well.
I took a quiz once that asked you to list 1-10 the most important items to take with you when stranded on the moon, far from base/ship/wherever. #4 or #5 as I recall was a .45 ACP pistol. After air, water, and food, a method of propulsion to get you back to base was the most important. I have no idea if this would work in a real world (or moon) situation, but I thought it was interesting.

 

[Rachen]

So we took the 9mm versus .45 ACP up to a whole new level, haven't we? No pun intended.

 

[brickeyee]

Space is mostly empty, and heat needs something to carry it away.

This statement reveals a complete lack of knowledge about radiation cooling a hot object in a vacuum.
There is NOTHING needed to carry the heat away.
It is electromagnetic radiation.

Or are you still looking for the 'ether' the Michelson & Morely showed did NOT exist?