mek42
Member
When the bullet travels through the barrel, does the part of the bullet that contacts the rifling become elevated in temperature?
If so, any idea how hot it gets?
If so, any idea how hot it gets?
bullet temperature
- Thread starter mek42
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JesseL
Member
We discussed this one a couple years ago, here's the link to the old thread.
moooose102
Member
man, i cant even imagine how hot it gets. why do you think it is called "hot lead". first, it is being FORCED into the rifleing, then shoved out of the barrel, and the longer the barrel, the longer friction has to do its work, PLUS it is coming down the tube at a blistering pace. i know it happens at a horrific speed, but when there is that much force involved, it has to transfer heat. i don't think that much heat would transfer INTO the bullet from the burning powder, the back face temperature would probably increase, but it happens so fast, that it wouldn't affect the overall temerature of the bullet.
Halo
Member
Shooting produces vaporized lead, so certainly the bullets are getting pretty hot. I don't know the formula to determine this, but bullets can come out in excess of 200,000 revolutions per minute. That's got to be some amazing friction between it and the rifling.
benEzra
Moderator Emeritus
Besides the friction caused by copper sliding against steel at one to two thousand miles per hour, the back of the bullet is in direct contact with 1000-degree gas at tens of thousands of psi for much of its journey down the barrel (typically 35,000 to 50,000 psi initially, dropping to around 3000 psi at the muzzle).
The combination of hot gases and pressure definitely elevates the bullet's temperature (undoubtedly more so for rifles than for handguns). Air friction can contribute some additional heating for the fastest bullets (at least for the first part of their flight), but once the drop below Mach 2 or so I'm sure the bullet temperature drops rapidly as it sheds heat to the air.
Impact can also raise the bullet's temperature via friction and deformation (that kinetic energy has to go somewhere when the bullet hits the backstop).
The combination of hot gases and pressure definitely elevates the bullet's temperature (undoubtedly more so for rifles than for handguns). Air friction can contribute some additional heating for the fastest bullets (at least for the first part of their flight), but once the drop below Mach 2 or so I'm sure the bullet temperature drops rapidly as it sheds heat to the air.
Impact can also raise the bullet's temperature via friction and deformation (that kinetic energy has to go somewhere when the bullet hits the backstop).
moooose102
Member
i hope its NOT with your TEETH!
longdayjake
Member
Hot Bullets
I work at a hospital as a security guard, and I have to guard the rooms every time we get a gun shot wound. I have seen autopsies of GSW victims and I have seen several "outcomes" of gunshots. Many times the surgeons leave the bullets inside the body because the bullets are so hot upon entering that they cauderize the tissue surrounding the bullet. I actually saw man that the cops killed with a shot to the head that had a graze wound on his cheek that was more of a burn than a cut. A cop that I talked to one day at the hospital said that it was very hot for about a minute after he was shot in the thigh. From what I understand, the friction caused by the inertial force of just the bullet flying through the air heats it up to the point that it would almost glow. I can't say for sure but that is what causes some bullets to come apart when you load them too hot. They go so fast that the heat softens the bullet and it can no longer maintain its current shape so it melts/disintegrates in midair. I also heard that the gravitational force of the spinning bullet pulls it apart, but I like the melting in midair explanation better.
I work at a hospital as a security guard, and I have to guard the rooms every time we get a gun shot wound. I have seen autopsies of GSW victims and I have seen several "outcomes" of gunshots. Many times the surgeons leave the bullets inside the body because the bullets are so hot upon entering that they cauderize the tissue surrounding the bullet. I actually saw man that the cops killed with a shot to the head that had a graze wound on his cheek that was more of a burn than a cut. A cop that I talked to one day at the hospital said that it was very hot for about a minute after he was shot in the thigh. From what I understand, the friction caused by the inertial force of just the bullet flying through the air heats it up to the point that it would almost glow. I can't say for sure but that is what causes some bullets to come apart when you load them too hot. They go so fast that the heat softens the bullet and it can no longer maintain its current shape so it melts/disintegrates in midair. I also heard that the gravitational force of the spinning bullet pulls it apart, but I like the melting in midair explanation better.
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