Home Forums Hunting & Shooting Ask The Gunwriters Temperature of Fired Bullet

True
Probably more like 200K, but true about not likely spinning 200k; 3000-4000 Revs would generally be a lot.
This I doubt. Some small portions of the bullet, yes, but not overall or average temperature. I think this could be disproven mathematically though I'm not going to attempt it.



Is one part of the barrel hotter than another? If so, friction should favor more heat in the faster section of the barrel. (The muzzle end.) If the chamber end heats up more quickly (less likely due to the greater barrel mass typically) then one could assume the heat comes more from the burning powder.

kenjs1 - IF you/we were to shoot in semi auto or full auto, several rounds THEN the friction heat would ADD up. However you still have the HEAT from BURNED powder from every round fired.

kalik did a very good job stating options and even then more heat comes from powder BURNED.

I'm NOT being critical BUT I don't understand why it is so hard for some, others beside you, to accept the majority of HEAT comes from BURNED powder.

? Are y'all making it harder to understand than it is ?

You are trying to oversimplify though. Burned powder heat has just a tiny percentage of the surface area of the bullet to work on and the heat transfer rate through the bullet is quite slow. Small portions of a second is not enough to transfer any subtantive quantity of energy, period.

Fact is there are only two sources of heat; primers and powder. That heat is converted to pressure which is then converted to heat through friction from the barrel. The surface area of the bullet/bore contact is far larger than the bullet base and far more likely to transfer powder energy to projectile heat.

Combustion heat on the bullet base is intense, but too brief to be meaningful in the grand scheme...

If anyone doubts where the majority of the heat buildup of a barrel comes from, have a friend fire an M1 Garand and catch the fired case in your hands!!!
__________
NRA Life,Endowment,Patron or Benefactor since '72.

That's a good point also, and the more massive chamber end of the barrel does heat up first (or faster) than the muzzle end, another indication that powder is creating heat. Also, anyone who has fired cast bullets in a 45-70, especially those of modest velocity, will understand that they, though they may be run at speeds very similar to the 22 LR, will heat up the barrel much more quickly than will a 22 LR. Even when you consider extra barrel mass of the 22 rimfire, it still isn't the friction that's making the heat. The lightest loads in a 45-70 burn a lot more powder (make more energy) than the heaviest 22 rimfire loads.

And yet we have FMJs with lead open bases and Gas checks invented for hardcasts.

Is or isn't?

Nav & Kilk - ahhh great points thanks. I probably do make it harder than it has to be but still glad I asked . Reminds me of a long discussion I had with a friend convined that bullets just had to be slower coming out of a semi auto. Thanks for some really good responses.

kensj1 - I have chronod semi autos w/ same ammo fired in bolt
actions.

Those I chronod. WERE SLOWER than from bolt actions.

Makes sense to me; some of gas pressure is bled off behind the
bullet to operate the action.

Not theoretical discussion. Chrono told the story I M E.

I told my friend if it might be more noticeable in a recoil operated semi auto than a gas. One person responded with several test results of his own and while there were differences they were within the standard deviation of a given load. So while there is a difference it isn't worth worrying about. Least that is what that test showed.

Kenjs1 - yes, I didn't mean to imply the semi auto loads were 100 fps slower.
I compared these before '95 & the 742 was a friend's.

Therefore I didn't keep a record of the exact diff. IIRC ? the diff. was @60 fps.
You are correct, the diff. wasn't terrific but the semi auto WAS slower using
the same loads at the same time.

At that time I was fanatical about getting ALL the vel. I could get. The loads
were NOT above the loading manual's max. Again IIRC it was 52 grs of
IMR 4895 w/150 HSP.

Thanks for your reply. Jerry

I caught an M1 Garand case on the inside of my forearm when it got into my shooting coat through the zipper at the elbow. I still have the scar to prove how hot it was. 2nd degree burns hurt!

That didn't come from friction, and the short time the case was in the chamber didn't keep it from absorbing a lot of heat from the burnt powder. Why would the barrel be any different?

Fast Ed

Fast Ed - That's the way I see it too.

thanks Jwall. This was an interesting thread. I wonder how many psi is required to cycle the bolt on that 742?

Temp?

Damned hot.

kenjs1 - w/o knowing the operating pressure of those loads it would be impossible to determine.

SPECULATION - I 'had' a hypothesis based upon 'supposed' figures

BUT I decided it's better to just not guess. Jerry