Heat generated per shot?

Interested

Id be interested if anyone had any info also. My concern would be any data would be specific to a given set of conditions that would change wildly if any variables were changed. ambient temp, wind speed, humidity, barrel start temp and the list goes on and on. Sorry if im preaching to the choir. It would be nice if there were some rough constants to follow though to find that middle ground as you stated. May I ask what you are trying to do?

Here's a start:

13. Distribution of the heat energy of the powder, p399, Hatcher's Notebook.

This is for the .30 service cartridge of the day (.30-06), and you may find later data with diligent tedious search, but this may be all you need. This data is in Calories.

Without reproducing the whole table, but in direct answer to your direct question, the total heat energy in that cartridge's powder charge of about 48 grains is approximately 28,852 Calories. It is not clear from the table whether this includes the heat of friction of the bullet going through the bore, which is 212 Calories. But this possible error is less than 1% of the total.

(Note that these energies were stated for single-based powders such as 4320, 4350, 4895, etc. Double-based powders containing nitroglycerin have considerably higher energies per unit of weight.)

A good start for an additional search might be by contacting SAAMI:

http://www.saami.org/

Terry, 230RN

ETA: Apparently, Hatcher's Notebook is online now as well as available on e-bay, etc.
http://www.scribd.com/doc/33538806/Hatcher-s-Notebook

Additional comment for OrdellRobbie

It's my opinion that the additional parameters you mentioned are such small extraneous variables in normal conditions, that the heat distribution of the extremely violent and energetic processes in normally firing a cartridge would not be affected much.

Note the "normal conditions" remark.

Yes, it's possible to blow up a gun with barely-safe handloads that were safe in normal temperatures but not if the gun were left in the sun for a half hour. But this is a result of accelerating the powder burning by the high temperatures, not as a result of somehow increasing the total chemical energy available by burning the powder. The difference is in whether the powder will progressively burn nicely versus practically detonating.

And of course, it is well known that muzzle velocity with vary with temperature slightly, but once again, this is because the burning rate changes, not because there may be slightly more or slightly less energy in the powder itself with different temperatures. (There may be other miniscule effects, like the bore opening up slightly because of expansion, etc.)

It is also well known that in extreme battle conditions and extreme testing, machine guns have been fired until their barrels were practically red hot.

Terry, 230RN

And remember the ejected brass is going to take a whole bunch of heat with it. Case less ammo has this problem, no brass, no heat going with it. So all of it ends up in the barrel and causes problems....

"And remember the ejected brass is going to take a whole bunch of heat with it. Case less ammo has this problem, no brass, no heat going with it. So all of it ends up in the barrel and causes problems.... "

That's a good point, but it is also well known that ejected brass from a semiauto or auto is very much hotter than the brass from a manually-operated firearm. This is because the case has some time to get rid of its heat to the steel of the chamber before the breech is manually opened.

You haven't lived until the .30-06 or .308 case from the guy firing the Garand left of you has gone down the back of your shooting jacket.

That's when you learn to wear a wide-brimmed campaign hat during the offhand, sitting, or kneeling stages of the matches.

Or at least turn your baseball cap around backwards.

In my experience, blackpowder loads tend to heat up a gun substantially more than smokeless powder loads. It doesn't take many shots of BP before you want to be very careful about touching any metal.

230RN said:

"And remember the ejected brass is going to take a whole bunch of heat with it. Case less ammo has this problem, no brass, no heat going with it. So all of it ends up in the barrel and causes problems.... "

That's a good point, but it is also well known that ejected brass from a semiauto or auto is very much hotter than the brass from a manually-operated firearm. This is because the case has some time to get rid of its heat to the steel of the chamber before the breech is manually opened.

You haven't lived until the .30-06 or .308 case from the guy firing the Garand left of you has gone down the back of your shooting jacket.

That's when you learn to wear a wide-brimmed campaign hat during the offhand, sitting, or kneeling stages of the matches.

Or at least turn your baseball cap around backwards.

Click to expand...

All the Commie guns are real brass flingers; AK, SKS, Makarov, Tokarov, and my CZ 52. I'm always getting complaints at the range about them. And I've got a few down the shirt as well.

Taking 230RN's number a bit farther, 28,852 calories converts to right around 89,000 foot pounds. That brings up the question of whether Hatcher was using calories or Calories. 1,000 calories = 1 Calorie.

At any rate, some of the energy of the powder is converted to ~3,000 foot-pounds of kinetic energy. Pretty much all the remainder is converted to heat.

Some heat is transferred to the barrel, some is carried off by the brass and the bullet, and some is exhausted into the atmosphere when the bullet uncorks the barrel.

Link to thread, containing more info. http://thefiringline.com/forums/showthread.php?t=375731

Ive seen some really stupid people shooting ARs at the range i go to. They load up a 30 round mag and burn threw it in a short period then sit the gun down in the rack just smoking hot. Then the next time they come back to shoot they cant hit a thing with it.

There are these plastic gun rests on the table tops supplied by the range and i see many of them with barrel burns in them where they have sat the barrel on while they chew threw a 30 round mag and the barrel melts into the rest.

I learn alot from these people

I dont have a large caliber AR but if i ever get one ill know what not to do.

The length and mass of the barrel will also affect how fast it heats up. A heavy target barrel will heat up more slowly than a light weight hunting barrel due to it's greater mass.

A short barrel ought to heat up less than a long barrel due to the fact that the hot gasses from the cartridge will exit it faster, and less barrel length in contact with the hot gas.

As a heat engine (using heat to do work) guns are actually not efficient at all.

A small traction of the energy present in the powder ends up being present in the bullets kinetic energy and rotational inertia.

Most is just wasted.

A long burst from a Ma Deuce generates enough heat to turn the barrel nearly white hot. I've seen .50 caliber machine gun barrels twisted and bent -- some of them with long gashes in the side, where the bullet keeps going straight and the heated barrel is drooping and soft.

http://www.dtic.mil/dtic/tr/fulltext/u2/a019649.pdf
http://www.dtic.mil/dtic/tr/fulltext/u2/a285699.pdf

These reports on the M16A1 and M4A1 should give you a nice start on your quest.

eldon519 said:

http://www.dtic.mil/dtic/tr/fulltext/u2/a019649.pdf
http://www.dtic.mil/dtic/tr/fulltext/u2/a285699.pdf

These reports on the M16A1 and M4A1 should give you a nice start on your quest.

Click to expand...

Good stuff. Well defined test method and conclusions.

Ron