machine gun barrel temp


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Jim_100
August 4, 2010, 01:23 PM
I recently read a discription of a machine gun barrel becoming white hot and it it being possible to see the darker bullet going down the barrel.
Is this possible or was it a writers exageration?
He also described the ejected brass as being so hot that they would stick to your skin like a tick.
Thanks.

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Bovice
August 4, 2010, 01:30 PM
I've never heard of metal becoming translucent.

I've also never heard of hot brass sticking to skin.

So it's an exaggeration.

stickhauler
August 4, 2010, 01:32 PM
It can't get that hot, the barrel would start to droop long before that. You'd get the receiver blowing up in your face shortly after it started to droop.

machine gun jenny
August 4, 2010, 04:01 PM
Have seen it. The barrels will droop if they are not supported. When we do T&E destruction FA rounds for our suppressors, the cans get red then white hot . The internals of the suppressor can also be seen like itís being x-rayed. Really cool and scary!

Here is a mg video I found on line for you.
http://www.youtube.com/watch?v=jFEafMjrlOw

GoingQuiet
August 4, 2010, 10:25 PM
http://www.everydaynodaysoff.com/2010/03/26/cooking-some-bacon-the-machine-gun-method/

Hot enough to cook with!

Jim Watson
August 4, 2010, 10:42 PM
Mssrs. Maxim and Browning kept it down to 212F with water cooling.

coltsfreak18
August 4, 2010, 10:47 PM
I've witnessed an mg42 becoming nearly white hot, mostly red, though, but I'm sure it could be done. The people who owned the mg42 said that they had seen it get so white hot that they could see the bullet.

shotgunjoel
August 4, 2010, 11:24 PM
I seriously doubt that you could see the bullet. Even in the barrel it's getting up to speed and going fast. Maybe someone with more knowledge of internal ballistics could help?

Zanad
August 5, 2010, 12:16 AM
I sorta agree that you cant see the actull bullet you may be able to see where the "cold" bullet is traveling down the barrell. dont believe me? try this: make a piece of steel white hot with a torch of some kind, then find a cold piece nd stick it on to the hot metal and watch what happens. the hot metal suddenly changes color when the colder metal contacts the hot.

this effect MAY be what the OP is talking about.


(I may have worked in a metal shop before the economy tanked)

mptrimshop
August 5, 2010, 12:46 AM
you couldn't see the bullet if go down the barrel if it was clear .....heck ya can"t see a bullet in the air after it's fired

dirtymike1
August 5, 2010, 11:38 AM
I sorta agree that you cant see the actull bullet you may be able to see where the "cold" bullet is traveling down the barrell. dont believe me? try this: make a piece of steel white hot with a torch of some kind, then find a cold piece nd stick it on to the hot metal and watch what happens. the hot metal suddenly changes color when the colder metal contacts the hot.

this effect MAY be what the OP is talking about.


(I may have worked in a metal shop before the economy tanked)

This is what I was going to say. It's not that you can see the actual bullet firing, it's that you can see the cool spot moving down the barrel.

This just makes me want to get a MG42 and try it out :evil:

dbb1776
August 5, 2010, 12:06 PM
Hot brass Does stick to you! I seen it. Just catch a piece of .22 brass out of a semi to see if you can. I only did it once.

medalguy
August 6, 2010, 07:28 PM
I have seen an M-60 fired so long the barrel got red hot and set the handguard on fire. That's hot.

W.E.G.
August 6, 2010, 07:56 PM
WHITE hot is probably a stretch.

http://i227.photobucket.com/albums/dd7/rkba2da/WECSOG/heatcolorsforsteel.gif

The vid shot with NV photo gear makes it look white in the vid.
The barrel is not really white hot. Its just the NV's limited (almost nonexistent) color resolution.

http://www.youtube.com/watch?v=A4edabxcJoA

A similar burst without NV shows the real color (salmon), and is pretty obvious we are talking about temps more than 600 degrees below "white hot."

http://www.youtube.com/watch?v=jFEafMjrlOw&NR

Its not that far-fetched to say you can "see" the bullet traveling down the barrel.
If you can see the a tracer bullet in the air, why couldn't you see the same bullet as it travels the barrel?
While I won't say I "see the bullet" in the barrel, I will say I see a pulsing color moving from the chamber toward the muzzle as the barrel heats.
I'm seeing the rapidly changing temperature signature of the barrel, caused by the bullet as it moves down the barrel.

http://www.youtube.com/watch?v=dGAwrmOapb4

I have witnessed hot shell casings adhere to flesh too.
Instantaneous second-degree burn.
The stick-ee usually won't hold still for a pic.

This one's my favorite.
http://www.youtube.com/watch?v=WxQXBueF4Bc

.
.
..

Mr.Davis
August 12, 2010, 03:57 PM
A friend's father said the open mouth of ejected brass stuck to his forearm while hunting once and burnt a ring there. I don't really have a reason to doubt him.

I do have a reason to doubt, however, the notion that you can "see" the bullet going down a gun's barrel when it's white hot. You can't even see a bullet under normal circumstances because it's going so fast.

WoofersInc
August 12, 2010, 04:16 PM
He also described the ejected brass as being so hot that they would stick to your skin like a tick

I have a scar in the perfect outline shape of a shell casing to prove this one is true. Case hit me in a spot I couldn't immediately get to and stuck giving me a deep 2nd degree burn.

rcmodel
August 12, 2010, 04:17 PM
I call BS.

A white hot barrel could not withstand the chamber pressure.
It would simply melt & blow up.

Steel begins to deform and lose tensile strength at cherry red. (1,400 degrees)
It melts & runs at white hot. (2,190 degrees)

Ask any welder.

rc

CoRoMo
August 12, 2010, 04:34 PM
http://www.youtube.com/watch?v=BNpw26Qt6Bg

Here's the video of the AR15 being shot full auto, mag after mag, until the barrel gets so hot that it begins to droop. When that happens, the whole upper fails in a kaboom.

vwfool
August 17, 2010, 12:33 AM
It is true about something getting so hot you can see movement of something inside of it. This is a picture of a hot housing on a 3524 Waukesha engine ran on natural gas. My IR temp gun only reads up to 999 degrees F, so I don't know the exact temp. It should be between 1000 and 1200 degrees. When you are looking at it at night you can "see" the impellor moving inside of the turbo's hot housing. Pretty cool :rolleyes:, punn intended:rolleyes:

126068

Chemistry Guy
August 17, 2010, 09:25 AM
A white hot barrel could not withstand the chamber pressure.
It would simply melt & blow up.

This is correct if you are talking about looking directly at it with your eyes. It is unlikely that the steel would be able to get much hotter than a dull red before the material fails. However there is a good chance that if you are taking video an optical effect could make the barrel appear white. The glowing of the steel is releasing a ton of electromagnetic radiation in the infrared, which could easily saturate the pixels if the appropriate filters are not being used, resulting in a white color. There is probably a chance that something hot enough close enough to your face could appear white due to a similar effect, but I don't know enough about the physiology of the eye to comment on that.

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