Bullet sparks
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230RN
2A was "political" when it was first adopted.
Any impact generates heat.
Larger impacts generate larger amounts of heat.
A large enough impact can generate enough heat to ignite, or simply bring to a glow, the particles that break off the two substances.
Just because it is easier to use flint and steel to make sparks, and we humans use it as such for convenience' sake, doesn't mean it can't happen with other things if there is enough velocity involved.
Get a ball of ice going fast enough and make it collide with a blob of methane gas, and it will make sparks.
Lots of them, sometimes visible for millions and millions of miles.
Consider, if you will, the collision of the Shoemaker-Levy comets on Jupiter.
Ice impacting methane.
Consider also, if you will, the impact of the 820 lb copper and aluminum "bullet" we shot at comet Tempel 1. (Attached)
Or, just look up at the night sky during a meteor shower. Rocks and ice cubes hitting just the plain old air of our little blue planet.
Any impact generates heat.
Larger impacts generate larger amounts of heat.
Larger impacts generate larger amounts of heat.
A large enough impact can generate enough heat to ignite, or simply bring to a glow, the particles that break off the two substances.
Just because it is easier to use flint and steel to make sparks, and we humans use it as such for convenience' sake, doesn't mean it can't happen with other things if there is enough velocity involved.
Get a ball of ice going fast enough and make it collide with a blob of methane gas, and it will make sparks.
Lots of them, sometimes visible for millions and millions of miles.
Consider, if you will, the collision of the Shoemaker-Levy comets on Jupiter.
Ice impacting methane.
Consider also, if you will, the impact of the 820 lb copper and aluminum "bullet" we shot at comet Tempel 1. (Attached)
Or, just look up at the night sky during a meteor shower. Rocks and ice cubes hitting just the plain old air of our little blue planet.
Any impact generates heat.
Larger impacts generate larger amounts of heat.
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macadore
Member
If I am not mistaken, bass hammers are used in environments with flammable gasses because a steel hammer striking other pieces of steel can cause sparks. It seems like a steel bullet striking another piece of steel could do the same thing.
230RN
2A was "political" when it was first adopted.
In that case, it's because the brass particles that might get knocked off on impact do not burn in air readily, like ferrous materials, and they're softer.
The softness accounts for the fact that on impact, the energy dissipation is slowed down because of deformation. Meaning the power dissipation occurs in a longer time, resulting in lower temperatures at the collision.
Remember that power is the rate at which energy is dissipated.
With much harder steel on steel (or flint), the power dissipation is at a greater rate, since things don't get out of each others' way, resulting in higher temperatures because of the greater power dissipation rate. At some point, the broken-off particles can be heated to almost their ignition point, and sometimes the oxidation which occurs at elevated but sub-ignition temperatures can bring the particles right up to their actual ignition point.
Iron oxidation (or rusting) produces a lot of heat. You don't see it if it's just a hunk of iron sitting out, rusting, in the weather, but it does.
(I point out that when using a torch to cut steel, some welders shut off the gas after they start the cut. The pure oxygen hitting the hot workpiece makes the iron burn directly, and melt without the aid of the gas. This keeps the workpiece hot, allowing the welder to proceed with the cut with no fuel beyond the burning of the iron itself. In addition, masses of iron/ steel, like turnings and chips, can start burning on their own if they get wet. A little moisture starts a little oxidation, which raises the temperature, which increases the oxidation rate, and soon you have an iron fire. Yes, Virginia, water can start fires.)
So. Consider a brass hammer hitting Tempel 1 (see above), like the copper and aluminum "bullet" we fired at it. You can bet it will throw sparks at the velocities involved.
The softness accounts for the fact that on impact, the energy dissipation is slowed down because of deformation. Meaning the power dissipation occurs in a longer time, resulting in lower temperatures at the collision.
Remember that power is the rate at which energy is dissipated.
With much harder steel on steel (or flint), the power dissipation is at a greater rate, since things don't get out of each others' way, resulting in higher temperatures because of the greater power dissipation rate. At some point, the broken-off particles can be heated to almost their ignition point, and sometimes the oxidation which occurs at elevated but sub-ignition temperatures can bring the particles right up to their actual ignition point.
Iron oxidation (or rusting) produces a lot of heat. You don't see it if it's just a hunk of iron sitting out, rusting, in the weather, but it does.
(I point out that when using a torch to cut steel, some welders shut off the gas after they start the cut. The pure oxygen hitting the hot workpiece makes the iron burn directly, and melt without the aid of the gas. This keeps the workpiece hot, allowing the welder to proceed with the cut with no fuel beyond the burning of the iron itself. In addition, masses of iron/ steel, like turnings and chips, can start burning on their own if they get wet. A little moisture starts a little oxidation, which raises the temperature, which increases the oxidation rate, and soon you have an iron fire. Yes, Virginia, water can start fires.)
So. Consider a brass hammer hitting Tempel 1 (see above), like the copper and aluminum "bullet" we fired at it. You can bet it will throw sparks at the velocities involved.
1911Tuner
Moderator Emeritus
Sparking requires heat and a goodly amount of carbon...neither of which lead or cupro-nickel have. Go hold a bullet against a grinding wheel and see if if sparks.
Iron is a pyrophoric metal. It will ignite on contact with the air. The higher the carbon content, the smaller the pieces are that break off when it strikes something, and the more it will spark.
Lead and copper aren't pyrophoric. If you're seeing sparks when your bullet impacts something, either there's something else involved, or the bullet jacket is made of mild steel...like wrought iron.
Hold wrought iron against a grinding wheel, and you'll get a small amount of erratic sparking. Use cold-rolled steel, and the sparking will increase, though still not in a spectacular way. Hold a piece of High-Speed steel to the grinder, and it'll look like the sparklers that most of us have burned ourselves with on July 4th.
Iron is a pyrophoric metal. It will ignite on contact with the air. The higher the carbon content, the smaller the pieces are that break off when it strikes something, and the more it will spark.
Lead and copper aren't pyrophoric. If you're seeing sparks when your bullet impacts something, either there's something else involved, or the bullet jacket is made of mild steel...like wrought iron.
Hold wrought iron against a grinding wheel, and you'll get a small amount of erratic sparking. Use cold-rolled steel, and the sparking will increase, though still not in a spectacular way. Hold a piece of High-Speed steel to the grinder, and it'll look like the sparklers that most of us have burned ourselves with on July 4th.
230RN
2A was "political" when it was first adopted.
The carbon "helps" in terms of initiating combustion (it's a good fuel) in the hard steel, but you have to look at it microscopically, not macroscopically.
Other materials are softer, hence have a tendency to move away and be cut off by the granules of the wheel (although softer materials tend to clog the wheel anyhow), whereas harder substances get more or less knocked off --that is, there is a higher microscopic power applied in a tiny area, resulting in higher temperatures.
Again, looking at it microscopically.
If you've ever ground cast iron, which has the highest carbon content but is pretty soft compared to hardened tool steel, you'll note that a lot fewer sparks are generated --compared to the tool steel, which throws a bright shower of sparks, as noted.
Also, the particles of the softer materials, instead of igniting like the iron in the steel, just tend to get quenched as they fly through the air. From personal experience, I can tell you that there is a small bright glow at the grinding point when you push a brass workpiece against a high speed grinding wheel. I had a 1/2 HP bench grinder which, I would brag, would eat a crowbar if you threw it at it, and I have seen this bright glow when I fed a brass rod against the wheel. (I was trying to dress a rather rough end of the rod. Yes, it loaded the wheel, but I kept a star wheel wheel dresser handy. I like my carborundum granules sharp.)
By the way, I think they use bronze hammers in mines and other flammable-gas or combustible powder areas rather than brass, simply because it's harder than brass.
You really have to look at things microscopically sometimes. My personal feeling is that the use of oil on sharpening stones is more to keep that microscopic edge cool while sharpening than to "float" particles away.
And if you don't believe that high temperatures can be generated in tiny areas, just try running your thumbnail briskly against your pants leg. You may burn yourself.
That's the old-fashioned way of lighting matches... if you remember that far back.
And hitting Tempel 1 with that brass or bronze hammer would have thrown sparks.
Even a lead hammer would have.
But that's at 10 kilometers per second.
About 22,000 miles per hour.
Macroscopically speaking.
Other materials are softer, hence have a tendency to move away and be cut off by the granules of the wheel (although softer materials tend to clog the wheel anyhow), whereas harder substances get more or less knocked off --that is, there is a higher microscopic power applied in a tiny area, resulting in higher temperatures.
Again, looking at it microscopically.
If you've ever ground cast iron, which has the highest carbon content but is pretty soft compared to hardened tool steel, you'll note that a lot fewer sparks are generated --compared to the tool steel, which throws a bright shower of sparks, as noted.
Also, the particles of the softer materials, instead of igniting like the iron in the steel, just tend to get quenched as they fly through the air. From personal experience, I can tell you that there is a small bright glow at the grinding point when you push a brass workpiece against a high speed grinding wheel. I had a 1/2 HP bench grinder which, I would brag, would eat a crowbar if you threw it at it, and I have seen this bright glow when I fed a brass rod against the wheel. (I was trying to dress a rather rough end of the rod. Yes, it loaded the wheel, but I kept a star wheel wheel dresser handy. I like my carborundum granules sharp.)
By the way, I think they use bronze hammers in mines and other flammable-gas or combustible powder areas rather than brass, simply because it's harder than brass.
You really have to look at things microscopically sometimes. My personal feeling is that the use of oil on sharpening stones is more to keep that microscopic edge cool while sharpening than to "float" particles away.
And if you don't believe that high temperatures can be generated in tiny areas, just try running your thumbnail briskly against your pants leg. You may burn yourself.
That's the old-fashioned way of lighting matches... if you remember that far back.
And hitting Tempel 1 with that brass or bronze hammer would have thrown sparks.
Even a lead hammer would have.
But that's at 10 kilometers per second.
About 22,000 miles per hour.
Macroscopically speaking.
1858rem
Member
totally agree with 230RN
1911Tuner
Moderator Emeritus
Yup. Anything will glow if it gets hot enough. Even a rock.
Press cast iron against a wheel aggressively, and it'll shower sparks, too.
Any metal that is a pyrophoric metal that will ignite spontaneously on contact with air will spark when fractured. The amount depends on how hard it is to fracture and how much heat is applied, and how quickly it's applied.
Finer grained steels spark more agressively than coarse-grained steels...like cast iron.
Anyway...a copper jacketed or antimonial lead bullet emitting even a small a shower of sparks on impact with a rock? I don't think so...not unless there are other materials involved.
1911Tuner
Moderator Emeritus
Maybe this'll help. My metallurgy classes were long, long ago in a galaxy far, far away.
http://www.survivaltopics.com/survival/flint-and-steel-what-causes-the-sparks/
http://www.survivaltopics.com/survival/flint-and-steel-what-causes-the-sparks/
lonegunman
Member
Some of the eastern european and russian ammo is actually guilded metal or steel jacketed and copper washed. When it hits a metal backstop or something hard it sparks nicely.
If you are shooting some other types of surplus, it may be unmarked tracer, incendiary or someother type of ammo that will spark.
Plenty of surplus is mild steel cored. It is not AP nor is it considered AP because it would normally penatrate a bullet proof vest with a lead core.
The cores get amazingly hot, if you find them after impact, some are blue from heat. There is nothing amazing or galactic in nature occuring.
If you are shooting some other types of surplus, it may be unmarked tracer, incendiary or someother type of ammo that will spark.
Plenty of surplus is mild steel cored. It is not AP nor is it considered AP because it would normally penatrate a bullet proof vest with a lead core.
The cores get amazingly hot, if you find them after impact, some are blue from heat. There is nothing amazing or galactic in nature occuring.
I've seen it mostly from carbine and rifle rounds impacting metal or concrete/stone.
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