Michigander
Member
Every post in this thread makes sense to me.
Every post in this thread makes sense to me.
Try to push a new 9mm bullet down the barrel of your favorite gun by hand and you will understand why it's possible for the bullet to actually be slowing down in a long barrel even though there is considerable pressure behind it.
I can't think how to explain why that's not right, but the speed of sound is not a limitation in this case.The pressure wave from the burning propellent is only capable of travelling at the speed of sound in the material in which it moves, which is the pressurized hot gas field in the barrel.
Schrodinger did both. And neither.Heisenberg might have posted here.
or he might not have.
As far as I know, there was a 9mm ammo designed for SMGs, called Hirtenberger.
Some muzzle flash results from the fact that some of the combustion PRODUCTS are flammable, but do not burn in the oxygen-starved environment behind the bullet. (The powder is self-oxidizing, but the combustion products aren't.) When some of those hot combustion products hit the air outside the barrel, they undergo further combustion and produce some visible flash. I think carbon monoxide and POSSIBLY hydrogen may be present in amounts sufficient to produce a flash. (And no, carbon monoxide poisoning isn't a problem because the CO is HOT and oxidizes to CO2 as soon as it encounters atmospheric oxygen.)That's what gets me. If a 9mm is hampered by a long barrel to the point it slows down, shouldn't there be no muzzle flash? If the projectile is being slowed, that tells me that the burning powder/expanding gases aren't doing their job, so to speak. They aren't pushing the bullet, so they must be losing their energy. Why, then, does the flash still happen? For that matter, why is it still comparably loud?
Actually, it is, but not the speed of sound in air; rather, the speed of sound in 35,000 psi, 1000-degree nitrocellulose/nitroglycerin decomposition products, which is WAY higher than the speed of sound in sea-level air. It is this factor that limits the ultimate speed of any gunpowder-driven projectile to under 7000 fps; the gas simply can't expand any faster than that, regardless of how light your projectile is.quote:
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The pressure wave from the burning propellent is only capable of travelling at the speed of sound in the material in which it moves, which is the pressurized hot gas field in the barrel.
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I can't think how to explain why that's not right, but the speed of sound is not a limitation in this case.