Bullet temp in flight

[RockyMtnMT]

The heat the air puts on a bullet in flight, is nowhere near the heat the friction in the barrel puts on it.

So, the test that I found recorded about <70*c leaving the barrel with cooling temps down range. If this is true, then there is no way to melt a tip.

 

[fordy]

Gday
Got no idea on anything tip related just never really seen any evidence that they do melt with the ones out of critters I've found but a few busted ones from certain angles / resistances

How about someone ask the guys that compete @ king of 2 mile as surely they would know

Cheers

 

[Doom2]

So, the test that I found recorded about <70*c leaving the barrel with cooling temps down range. If this is true, then there is no way to melt a tip.

I read the entire paper and the only measured data was just downstream of the barrels and ~50yds down range. The 50yd data was not included. All other data was calculated and did not included the effects of aerodynamic heating. Their model is flawed based on the information provided in the paper. It is especially incorrect in the case of rifle bullets traveling at supersonic speed.

 

[65WSM]

I wore out a .17 Remington Lilja barrel shooting at sage rats. I decided that I believe that hollow point bullets are more accurate than tipped bullets. I have worn out three .204 Ruger, a .20 PPC and ,20 BR barrels at the same project. You have to switch rifles frequently to cool the barrels. .20 caliber tipped bullets have a little more metal as a heat sink but with 26 inch barrels, they fly well above mach 3 from these cartridges. All of my sage rat rifles wear 50X or more powerful scopes. I believe that if you shoot at 200 yards max, you won't notice much difference. If your bullets go mach 2 with a tail wind, you won't notice much difference. On 400 yard and further shots, I believe that you might see mysterious bullet behavior.

I shot a couple of thousand 77 gr Tipped Match Kings in the .224 Valkyrie. The velocity from the 24 inch Valkyrie barrel is 2800 fps. When I shot those same bullets in the .22 - 6 X 47 Lapua Ackley Improved and the .22 - 250 Ackley at 3350 to 3400 fps they grouped accurately at 300 yards but were all over the paper at 400? The 77gr HPBT from Nosler and 77gr MatchKings were normally behaved.

 

[RockyMtnMT]

I read the entire paper and the only measured data was just downstream of the barrels and ~50yds down range. The 50yd data was not included. All other data was calculated and did not included the effects of aerodynamic heating. Their model is flawed based on the information provided in the paper. It is especially incorrect in the case of rifle bullets traveling at supersonic speed.

I must have miss read it. I could've sworn they quoted down range temp loss.

 

[Gorill@]

Exactly. That is the question. How hot in sub 2 seconds of flight with constantly degrading velocity?

It sounds like the hottest it could possibly be is 900*f? How hot does a bullet get if it is introduced to that temp for 1 second? I'm thinking 900* is to much?

No idea without a infrared device.

 

[Jonoton]

Hardware and computational costs for infrared would preclude any study to support our interests. Perhaps a masters or PhD candidate choosing it for a thesis project could get some tunnel time. Existing studies are of the Raytheon-working-on-hypersonic-missiles type, I imagine.

IR Thermography

 

[Doom2]

Actually what we are discussing has been experimentally determined and modeled. Whether we are dealing with a bullet, the X-15 rocket plane, the Bell X-1 or the Space shuttle the issues and physics are the same. Because the bullet is a passive projectile it does not have a significant flight time therefor the amount of heat it absorbs is limited.

You may find it interesting that the Bell X-1 rocket plane's fuselage was modeled after the 50 BMG bullet which was know to be stable in supersonic flight. The Bell X1-B was equipped with instrumentation to measure aerodynamic heating. This experimentation occurred during the late 1940's to 1955. This provided an enormous amount of knowledge about supersonic flight up to about Mach 2 (2250 fps).

In the late 1950 through 1968 the X-15 explored the high supersonic low hypersonic region up to Mach 6+ (6600+ fps). There were addition X planes later, many of which were used to investigate drag/lift characteristics of various shapes.

As to whether or not the tip used on the Hornady bullets actually deformed is debatable the fact exists that there is a mechanism that can expose the tip to temperatures high enough to soften many elastomers/polymers. The desire to achieve a high BC drives the desire to achieve as pointed a tip as possible but that desire increases the likelihood that the tip will melt due to its small mass and the fact that the stagnation point may actually occur on the tip. I will say that the release of the Hornady information came at a time that bullet manufactures were concentrating on long range bullet capability and thus it is reasonable to expect that this problem could show up at that time.

 

[Hard rock]

Actually what we are discussing has been experimentally determined and modeled. Whether we are dealing with a bullet, the X-15 rocket plane, the Bell X-1 or the Space shuttle the issues and physics are the same. Because the bullet is a passive projectile it does not have a significant flight time therefor the amount of heat it absorbs is limited.

You may find it interesting that the Bell X-1 rocket plane's fuselage was modeled after the 50 BMG bullet which was know to be stable in supersonic flight. The Bell X1-B was equipped with instrumentation to measure aerodynamic heating. This experimentation occurred during the late 1940's to 1955. This provided an enormous amount of knowledge about supersonic flight up to about Mach 2 (2250 fps).

In the late 1950 through 1968 the X-15 explored the high supersonic low hypersonic region up to Mach 6+ (6600+ fps). There were addition X planes later, many of which were used to investigate drag/lift characteristics of various shapes.

As to whether or not the tip used on the Hornady bullets actually deformed is debatable the fact exists that there is a mechanism that can expose the tip to temperatures high enough to soften many elastomers/polymers. The desire to achieve a high BC drives the desire to achieve as pointed a tip as possible but that desire increases the likelihood that the tip will melt due to its small mass and the fact that the stagnation point may actually occur on the tip. I will say that the release of the Hornady information came at a time that bullet manufactures were concentrating on long range bullet capability and thus it is reasonable to expect that this problem could show up at that time.

Has any one ever thought of a carbide tipped bullet , would that even be practical ?

 

[Doom2]

Armor piercing bullets use carbide penetrators but it not an exposed tip, its within the jacket.

 

[Hard rock]

Armor piercing bullets use carbide penetrators but it not an exposed tip, its within the jacket.

I wonder how those wood work exposed , it seems they could be as pointed as possible , with no worries of heat or distortion, just a thought .