Random question i've never heard a good answer to


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mattamus1987
February 2, 2013, 12:19 PM
I fire a .223 our of my AR. The spent case is scalding hot.

I fire a .30-06 out my browning. The spent case is barely warm to the touch.

Whats with the huge difference in temperature of the fired cases. Yes there is substantially more brass in the 30-06 case and would take more energy to heat up but is that all thats going on here? And you cant say powder burn rates because ive had .223 loads and 30-06 loads with IMR 4895 and it didn't make a difference.

Anyways this dosent really matter im just bored today.

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fallout mike
February 2, 2013, 12:21 PM
One is scalding hot bc the temp is higher than the one that is barely warm. Hope this is the answer you were looking for.

fallout mike
February 2, 2013, 12:22 PM
Im bored as well.:D

RandyP
February 2, 2013, 12:26 PM
Heat transfer is heat transfer - the reverse of what we experience with brass happens in cooking - after removal the tin foil covering the casserole dish will be cool to the touch in seconds - that baking dish will stay screaming hot for a looong time.

gspn
February 2, 2013, 12:31 PM
Is the first shot out of your AR hot? Or are you talking about one of the casings that come out after perhaps 10 or 20 or 30 shots?

The more you shoot the hotter it gets. In general an AR is going to see a much higher volume of fire than a .30-06.

I don't recall checking the first piece of brass out of my AR's so I don't know...the later ones are hotter than three hells because the gun has heated up.

Now you have me curious though...but I can't step out back and start shooting because the city frowns upon it. Now I'm stuck with a question I can't answer...thanks.

USSR
February 2, 2013, 12:35 PM
Heat transfer from the case to the chamber. Your .223 case is being extracted from the chamber before it can transfer much heat to the chamber walls. Fire your .30-06 out of a M1 Garand instead of your Browning, and you will have one hot .30-06 case as well.

Don

Elkins45
February 2, 2013, 12:37 PM
Surface area. The 06 has more surface area in contact with the barrel, allowing the chamber to be a better heat sink.

rcmodel
February 2, 2013, 12:39 PM
Heres a possible answer.

The .223 case is ejected instantly from your AR-15 before there is much chance of heat transfer to the colder barrel cooling it off.

Is your 30-06 a bolt-action?
If so, I don't care how fast you are operating it, you ain't as fast as a gas operated semi-auto.

So the 30-06 case has more time to cool off in the chamber before it is ejected.


rc

Fire_Moose
February 2, 2013, 12:41 PM
The other day I noticed something weird, ants would swarm all over our hot brass. As soon as it. Cooled down they left.

Sent from my CZ85 Combat

mdi
February 2, 2013, 12:47 PM
Combustion temperature of the powder used. .223 loads use a faster/hotter burning powder than 30-06. My 9mm brass is warmer than my .44 Magnum brass immediately after firing; 9mm powder, upper loads of W231, .44 Magnum, lower mid-range loads of 2400...

higgite
February 2, 2013, 01:00 PM
Heres a possible answer.

The .223 case is ejected instantly from your AR-15 before there is much chance of heat transfer to the colder barrel cooling it off.

Is your 30-06 a bolt-action?
If so, I don't care how fast you are operating it, you ain't as fast as a gas operated semi-auto.

So the 30-06 case has more time to cool off in the chamber before it is ejected.


rc
This ^^^

Lost Sheep
February 2, 2013, 02:57 PM
Combustion temperature of the powder used. .223 loads use a faster/hotter burning powder than 30-06. My 9mm brass is warmer than my .44 Magnum brass immediately after firing; 9mm powder, upper loads of W231, .44 Magnum, lower mid-range loads of 2400...
And you cant say powder burn rates because ive had .223 loads and 30-06 loads with IMR 4895 and it didn't make a difference.
Sorry, no cigar for you, mdi.

There might be some temperature difference because the case volume is substantially smaller in the .223, contributing to higher pressure and temperature, but I am sure the difference is very small. The pressure operating range of any given powder would be the same.

Mystery. Needs more information. Action type, specific load data (so we can estimate pressure), gspn's question in post #5, etc.

Lost Sheep

gamestalker
February 2, 2013, 03:37 PM
I've wondered the same thing for a long time. I can run 5 stout cartridges through my 7 mag and the brass is barely even warm to the touch. And unless I've heated the barrel up enough to cause thermal transfer to the chamber, and then leave a cartridge in the chamber for several minutes, the cartridge doesn't get hot. But brass from the AR will come out extremely hot, even the first round.

GS

rcmodel
February 2, 2013, 04:11 PM
Like I said in post #5.

The case is being ejected from a semi-auto almost while the fire is still lit, and there is no time for heat transfer from the case to the chamber.

You can't operate a bolt-action that fast, so heat transfer is more complete, no matter how fast you try to operate it.

rc

murf
February 2, 2013, 04:22 PM
mattamus1987,

does your 223 ammo have a coating on it? if so, that could be insulating and preventing the heat transfer that is happening with that 30-06 round.

murf

119er
February 2, 2013, 04:24 PM
I'll buy in with RC. The same .30-06 ammunition coming out of my 1903 and my garand are two different animals as far as temperature. I'm no thermodynamics whiz, but I'm sure heat will transfer much more rapidly through metal to metal contact than through metal to air. Think double pane windows for example. Add to that the friction of being yanked from the chamber it any exists.

Elkins45
February 2, 2013, 04:25 PM
Like I said in post #5.

The case is being ejected from a semi-auto almost while the fire is still lit, and there is no time for heat transfer from the case to the chamber.

You can't operate a bolt-action that fast, so heat transfer is more complete, no matter how fast you try to operate it.

rc
Assuming your assumption is correct (bolt gun in 06 vs auto in 223) then this is the best answer. I said greater surface area on the assumption the OP was comparing apples to apples and was shooting a BAR. Even a 1/2 second delay before working the bolt allows for a lot of heat to bleed off.

Do we know for certain what kind of gun the 'Browning' is?

rcmodel
February 2, 2013, 04:35 PM
No, but it isn't a modern BAR or they would come out just as hot as his AR-15.

rc

JSmith
February 2, 2013, 04:39 PM
I'd guess it's because there's more mass in the .30-06 case. .30-06: ~186 gr./case, .223 ~97 gr. That's almost twice as much metal.

tbob38
February 2, 2013, 04:55 PM
The 30-06 brass from an M1 Garand is scalding hot, just like the brass from the AR. No time for the chamber walls to cool the case in the semi-automatic.

rcmodel
February 2, 2013, 04:58 PM
Good luck with that explanation!! :D

It hasn't worked for USSR or me yet!

rc

savanahsdad
February 2, 2013, 05:22 PM
223 is smaller than the 30/06 , so it heats faster , it should cool faster too take a 223 ,hold the base and then use a bic-lighter at the neck and see how fast the base gets hot , then do the same with the 30/06, and see how slow it heats up ,
this will be the same for any brass , less brass ,the faster it will heat up
or try this take 223 brass hold over open flame for 3sec, then 30/06 over same flame for 3sec, see witch gets hotter,

NOTE: I'm just guessing , and we still don't know if the OP's Browning is a BAR or an A-Bolt

floydster
February 2, 2013, 05:28 PM
The brass that ejects from my Win Mod. 100 auto is hotter then the gal I had out last night.

Smokeyloads

Rottweiler
February 2, 2013, 05:37 PM
Moose, are they FIRE ants? sorry, I had to ask

savanahsdad
February 2, 2013, 05:38 PM
The brass that ejects from my Win Mod. 100 auto is hotter then the gal I had out last night.

Smokeyloads
and that my friend is why we don't drink when we go shooting and do when ....... well you get the point... lol.....

JLDickmon
February 2, 2013, 06:25 PM
The brass that ejects from my Win Mod. 100 auto is hotter then the gal I had out last night.

Smokeyloads
I'm leaving that one alone..

mattamus1987
February 2, 2013, 06:53 PM
Ok fair enough, I dont own an M1 or any other auto loading 30-06, mine is in fact a bolt gun. Next time I see someone shooting a M1 im gonna scoop up his brass right after fired and squeeze it as hard as I can in my fist. Maybe that will shut me up!

cfullgraf
February 2, 2013, 07:40 PM
Heat transfer from the case to the chamber. Your .223 case is being extracted from the chamber before it can transfer much heat to the chamber walls. Fire your .30-06 out of a M1 Garand instead of your Browning, and you will have one hot .30-06 case as well.



Right.

The cases frome 223 Remington fired in my cold AR come out hot enough to burn my hands yet those same 223 Remington loads fired in my bolt 223 Reminton are only warm to the touch.

The extra time the case stays in the bolt rifle allows the heat to transfer.

Same for cases fired from semi-auto and bolt rifles in 308 Win and 30-06.

rcmodel
February 2, 2013, 07:55 PM
Use your bare hand to catch your buddy's little .45 ACP, 9mm, or .380 pistol cases out of ejection mid-flight sometime.
(You know it beats crawling around on the ground picking up brass, right!)

I GayRon-TeeYa it won't take you long to look at it!!

Yet amazingly, .44 Magnum cases are almost cool to the touch when you eject them out of a revolver cylinder.

Or take for instance a .22 LR case, hot out of a semi-auto pistol or rifle down your shirt collar!
You will be stripping down to your shorts right there on the range in front of everybody to get it off your baby soft & tender white belly skin!!

The same exact .22 LR case out of a bolt-action or revolver isn't even warm.

Maybe that will shut me up!You can bet on it!!

rc

highlander 5
February 2, 2013, 08:32 PM
Anyone ever have a 45 ACP case go down thier shirt? That will get your attention real fast,but the same round fired from a 625 is cool maybe warm to the touch upon extraction.

tbob38
February 2, 2013, 09:25 PM
Ok fair enough, I dont own an M1 or any other auto loading 30-06, mine is in fact a bolt gun. Next time I see someone shooting a M1 im gonna scoop up his brass right after fired and squeeze it as hard as I can in my fist. Maybe that will shut me up!
You live anywhere near SW Utah? We can settle this real quick.

rcmodel
February 2, 2013, 10:31 PM
Or, you could go to a machinegun shoot sometime, and lay your bare arm under a Browning 30-06 MG for a full belt or two.

You will be going to the ER for burn treatment afterward to get the 30-06 GI head-stamp tattoo burns off your arm!

rc

hAkron
February 2, 2013, 10:46 PM
Wouldn't the operation of an AR or AK type of rifle be hotter in general because rather than expelling the hot gasses all out of the muzzle end, some of the gasses are cycled back through the gun to operate 'gas operated' parts of the gun? Would any of that hot gas reach the spent case?

cfullgraf
February 2, 2013, 11:08 PM
With a cold gun, no, the gases from an AR do not directly impinge on the cartridge but inside of the bolt.

Of course, as an AR fires more rounds, the gas will heat up the bolt. But the ejected case is still hot when ejected from a cold gun.

I believe an AK is a piston gun and no gasses get into the bolt from the gas system so the action takes a bit longer to heat up. Corrections greatly accepted on the AK accepted if necessary.

rcmodel
February 2, 2013, 11:11 PM
Wouldn't the operation of an AR or AK type of rifle be hotter in general No.

All types of gas operated firearms use expanding hot powder gas to operate the action.

That generally occurs 10" - 14" up the barrel on a rifle, where the gas port is drilled into the bore.

In an AK, or AR, none of the hot gas from the gas port in the barrel reaches the fired case.
In an AK, the gas piston cycles and the hot gas is expelled well in front of the chamber.
With an AR, the gas is directed back through the gas tube, into the bolt carrier, where it drives the bolt carrier backward off the bolt to unlock it and allow case extraction and ejection.

Yes, a DI AR-15 runs hotter then a GP AK-47.

But neither one has anything to do with transferring heat to the fired case.

By the time the hot gas gets to the gas port in the barrel to do anything, the bullet is gone, the fire inside the chamber is out, and the pressure has already dropped enough to allow case extraction.

As a matter of fact, the fired case carrying off heat from a full-auto firearm is a design criteria.

If the brass didn't carry excess heat out of the gun fast as it was fired?
The gun would eventually melt.



Food for thought:
An AR-15 can cycle at 750 to 1,000+ rounds per minute in full auto operation.

For the math challenged like me?
Thats 12.5 to 17+ rounds per second getting fired and ejected, per second.

How much heat transfer from the case to the chamber to cool the cases do you think can happen in that length of time??

Or, lets see you run a bolt action that fast and eject hot cases!

rc

colorado_handgunner
February 2, 2013, 11:13 PM
Anyone ever have a 45 ACP case go down thier shirt? That will get your attention real fast

Had a 40 wedge between my safety glasses and temple once. Got a decent burn. Had the piece of mind to place weapon facing down range first before removing though, hence the burn.

Sent from my DROID RAZR using Tapatalk 2

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