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Temp. of bullet

Bryan, have you ever done any calculations on how hot a bullet gets after it is shot? Just wondering, I know I have been hit with ricochets and seen them hit nearby, at 1000 yrds after they hit the impact area. You do not want to pick them up! Can they be pushed fast enough to melt the lead?
 
Bob Sebold said:
Bryan, have you ever done any calculations on how hot a bullet gets after it is shot? Just wondering, I know I have been hit with ricochets and seen them hit nearby, at 1000 yrds after they hit the impact area. You do not want to pick them up! Can they be pushed fast enough to melt the lead?

Interesting question.
It must be air friction that makes them hot at 1000 yards?
 
Friction heat is a major player, as well as is drag heat. And the base is subject to combustion heat as well.
Bullets are very hot upon arrival at the targets. Digging them out of a 1007yd sand embankment and hitting them with a temp gun immediately upon impact, they were very hot still (+500-F). Was trying to figure out if moly-coated bullets arrived cooler, but had inconclusive results to form an opinion from.
Donovan
 
There has to be a good deal of friction and energy transfer in the sand bank to decelerate that bullet. That might have an effect.
 
Attaching a picture of a 30-cal bullet in flight captured by Infrared (IR) Imaging
 

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A couple of thoughts on the picture:

IIRC: Lead melts ~750 F

With the very short flight time, the temperature may not fully conduct to the core enroute to the target, but it strikes me that a hunting bullet would have a hard time holding on to its core if the edges are starting to melt.

I also was wondering how far downrange that image was taken. The reason I ask is that the meplat temperature seems low compared to the anecdotal friction heating of airplanes at high mach numbers. My thought is that the friction heating takes time and the bullet may not have been in flight long enough to reach full temperature.

I realize that friction heating in this instance is transient in nature as the bullet decelerates continuously in flight, just curious about the photo.

Thanks for posting it - I'm going to scratch my head about those temps for a while...
 
Busdriver -
The image was captured at 20-yds.

It's kind of a miracle in some ways that our bullets perform as well as they they do, for all the stress and strain there put through (combustion, barrel constrictions, friction, RPM, speed, drag forces, etc...).

Donovan
 
My only contribution is relative - got shot at about 80 yards range with a "pass through" hit (no bone contact); it felt about the same as someone tapping the hot end of a cigarette on your arm or hand.

Not a real precise measurement, but at least we know it gets warm.... ::)
 
Donavan,thanks for posting that picture,I had no idea a bullet gets that hot. I am going to email it to a friend that doesn't believe bullets get that hot. Again thanks for the pic.
 
While working up some loads for a 1:7 twist .223AI I tried some of the then new 90 gr. Sierra MK.
Initial testing was done at 30 yards, just to get the new gun lined up with the scope.
Very few of the bullets ever got to the target.
The usual results were 2-3 relatively large, ragged holes, along with hundreds of various sized round holes ranging in size from a pin hole to a few approximately 1/64th inch in diameter.
This told me that the lead inside the .223 bullet was molten, and the bullet jacket came apart very quickly after leaving the muzzle, resulting in a spray of molten lead.

By the way, 90 gr JLK .224 bullets held together just fine at velocities later determined to be around 2900 fps.

I can not see the bullet gaining temperature as it flies through the air, I think the maximum bullet temperature is obtained when it is undergoing extreme friction traveling down the bbl with around 5000 deg F contacting the base from the hot powder gases.
 
I can relate one instance when I was blowing up a few bullets at the end of a 20 shot string. The bullets started "smoking" down range. My scorer noticed it first. Conditions where very good for viewing. They smoked hotter and hotter until the first one blew up at around 200 yards. Just a little POOF. Since it was the first time I ever saw that I was stunned. I shot 4 more with the same results.

All blew up at around 200 yards. There was nothing on the paper at 1000 yards. They way I think this happened is the bullet got hot enough to melt the lead. I believe this took a little time otherwise they would have blown up near the muzzle. I have heard of many others that this has happened to. Nobody seems to know why. These bullets that I shot "looked hot" going down range. Of course I have know way of knowing that for sure. Velocities for these 6.5 MM 142's should have been around 3000 FPS. When it was cooler in the day I had no problems.

I left the box open and out in the sun on a very hot day. I am sure they might have been going faster than normal. The first 12 bullets went out fine. Then maybe 3 or 4 that smoked. Then I shot 5 that all blew up. At that time I thought it was kind of interesting and since I was already shooting poorly I did not figure a few more rounds coming up misses would matter. It is not an experiment I would wish to repeat today.
 
I shoot paper for fun and varmints( ghogs) because they are there. I'v seem many entrance wounds on instant kills where the flesh is charred...crusty and hard. This tissue is cooked! I favor friction as the main source of heat. I believe I read, maybe by litz himself, bullet blowups are the result of the lead core melting, due to frictional heat. Thin jacketed varmint bullets can do this often if spun too fast. My 22BR 8 twist will not get a berger 64 gr bullet to a 100 yd target...it looks like I hit a small clay pigeon at 50-75 yards...kinda cool in it's own way.
 

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