About powder burning without outside oxygen

M

markofkane

New member
For many years, I've wondered how gunpowder, or any black powder, can burn inside of a tightly enclosed space. From firecrackers to ammo shells.
I got to thinking about it last night, again, (my computer is upstairs, and I did not feeling like going up and researching)
I thought, "maybe the powder makes it's own (or contains) oxygen" and according to certain website, I was right!
I know this is the black powder section, but was the most appropriate forum I could find.
 
Smokeless burns at the same rate whether in open air or enclosed. Black burns faster in open air.
 
That's what I figured. All these years of wondering. I was always told you need 3 things for fire (fuel, heat, and oxygen). Well, that is one age old mystery for me, solved. :cool::cool:
 
Hawg Haggen said:
Smokeless burns at the same rate whether in open air or enclosed. Black burns faster in open air.
Click to expand...

Huh?:confused:
Smokeless burns very slowly in the open, black powder goes "poof" in my own personal experience.
I won't hesitate to set fire to a small pile of smokeless powder with a match. For black powder, that match needs to be on the end of a long stick or my hand will stink like burning hair.

I think you got it backwards.
 
Oxygen source for black powder

The oxygen source, in classic English, is saltpeter.

The standard chemical name is Potassium nitrate (KNO3).

When heated, the stuff gives up a fair bit of oxygen and this is what the charcoal and sulfur get burned with.

Standard smokeless powder can be a bit more complicated because the nitrate radical is typically attached to a cellulose molecule (guncotton) so it doesn't need the charcoal and sulfur as fuel.
 
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Smokeless burns very slowly in the open, black powder goes "poof" in my own personal experience.
I won't hesitate to set fire to a small pile of smokeless powder with a match. For black powder, that match needs to be on the end of a long stick or my hand will stink like burning hair.

I think you got it backwards.
Click to expand...
+1
Correct.

Pete
 
Black Powder( although a propellant) was the first explosive to be used by man. It served well as a powder for firearms, but was always a problem because of the almost instant combustion, as well as the cleaning involved.
As smokeless progressed, it was considered to be more of a propellant, rather than an explosive because of the controlled rate of burn it produces.
Either one will produce its own oxygen when burning. Smokeless does it with a more controlled push of the bullet, rather than the more instant bang of the black powder.
The burn difference between the two, will change chamber pressures drastically, and is why you are not supposed to use smokeless in a powder rifle.

Make any sense?
 
When I was in the Army, every time we got ready to do a gunnery rotation with the tanks, we would have to watch the same safety video. Part of the video showed how a round for our 120mm cannons would burn like crazy under 10 feet of water. Of course, the powder inside was quite a bit more 'high-tech' than black powder, but it does point out how a material can be 'self-oxygenating'.
 
KNo3 (SaltPeter) "is" the oxygen catalyst in black powder.

Black powder is extremely flammable..That is why the explosive rating, but it is not a true explosive. Black powder burns in at almost the same speed no matter if confined or in the open. It is much slower burning in a confined space than any high explosive or even smokeless nitro powder.

Black powder burns at 3000fps..TNT burns at 22,000fps...quite a difference between a high explosive and a highly flammable substance.
 
thats the oddity of black powder.

modern explosives funciton on the basis of producing massive pressure at massive speed.

black powder creates VOLUME of gas with a modicum of pressure and speed.
 
freedom475,

Thanks! I hadn't thought about the difference in burn speed and had, in fact, not considered the difference between deflagration (black powder) and detonation (TNT) in this discussion.

You've reminded me of another technicality in the difference between black powder, smokeless powder, and high explosives. The reason black powder is so slow is that the KNO3, carbon, and sulfur have to break apart into their constituent atoms in order to combine into combustion products. TNT, on the other hand, goes so fast because the reaction is intramolecular, meaning that the atoms only have to rearrange themselves, meaning that the number of moles of gas increase very rapidly. Settling down into water, CO, CO2, N2, and other atoms happens at a more leisurely pace with perhaps a decrease in the number of moles but the heat released drives a further increase in pressure.

I'm glad that you mentioned, because it helps in clarifying a smoky picture! (My explanation probably doesn't clarify as much, even though it has some interest for a few folks.)
 
TNT does not have quite enough oxygen to completely convert all of its carbon into CO2 or even carbon monoxide, thus its rather sooty explosion. Because of this, its often blended with some overoxidized high explosive like ammonium nitrate resulting in an explosive mixture that is more powerful than the sum of the components.
 
Both black powder and smokeless powder contain their own oxygen, for burning.
Consequently, either firearm could be used in the vacuum of Space.
Prior to the first moon landing, a number of unmanned probes were sent to the Moon by NASA.
On one of those unmanned landings, a .45-caliber bullet was fired into the surface while the result was televised back to Earth.
It was done to test the firmness of the lunar surface. If the bullet quickly disappeared into the surface, then concerns about its ability to hold the manned, Lunar Excursion Module (LEM) were raised.
Fortunately, enough dust and dirt were raised to indicate it could support the LEM.
This is likely the first instance of a cartridge being fired in Space; I've never heard of earlier instances.

And if we go to war in Space, we wouldn't need fancy ray guns and such. A .22 rimfire would be enough to puncture an enemy's spacesuit. Space vehicles could probably be punctured with the likes of the .30 Carbine.
Recoil becomes a factor when shooting. In weightlessness, you'd be moved backwards with each shot so you'd want a firearm with low recoil -- a 7.62 machine gun would send you drifting.

Shooting at Earth would send bullets into the atmosphere, where they'd burn up in the atmosphere and create "shooting stars." Larger bullets might even reach Earth, but as a molten lump. Copper-jacketed bullets would create green meteors; I'm uncertain what color lead would create.

Personally, I hope that war never erupts in Space, nor that we Earthlings never have a reason to bring a firearm into space.
But yes, firearms would function in Space because gunpowder contains its own oxygen.
 
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