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| Thanks Hobie, that's what I was afraid I'd hear. Live and learn, I guess, BUT it does give me an excuse to take a trip into town to visit the gunshop! |
| | | Posts: 1275 | Location: Sydney, New South Wales, Australia | Registered: 02 May 2002 | 
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| I thought the critical temperature was 450 to 550 deg before any annealing occured. Brass alloys are used in industrial heat exchangers, primarily in hot water service all the time at temperatures in the 200 to 250 range with no metallurgical worries. Your car engine has brass cooling water parts that operate at 230deg.
Hold on....
Well, I just went down the hall and found out more than I ever wanted to know about brass from our staff metallurgist. The short story is, no problem. The lowest service rating for any brass before changes occurs is 400 deg F. This of course has a safety factor built in. Most brasses, including cartridge brass, are above this according to his data books.
Incidentally, I did find out that brass is initially annealed at higher temperatures (over 800deg). This is to insure large crystals and even distribution. As it is cold worked, reannealing takes place at lower temperatures due to a decrease in grain size. |
| | | Posts: 1238 | Location: Lexington, Kentucky, USA | Registered: 04 February 2003 |
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| Just to make it 3:1 for reuse.
This Mechanical Engineer dries his 8x68 brass in the oven too. Also at above 220 F to ensure complete drynesss.
Now 8x68 factory ammo seems to operate above 55 000 psi and I have reloaded some cases more than 5 times and they are still going strong. Ok - I do load them down a bit but they still need trimming after 3 shots.
Sleep easily
cheers edi |
| | | Posts: 222 | Location: Cape Town South Africa | Registered: 02 June 2002 |
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| From this metallurgist - you have no problem. |
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| My only question is ......How hot does the brass get when you fire it? I imagine it gets much hotter. I'd reuse it. |
| | | Posts: 258 | Location: Baltimore, Maryland US of A | Registered: 01 June 2001 |
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| As to how hot a case gets!
In my youth I had a job that involved titrating something at 60 C (determining phosphates or something). After a month or so we could hold the neck of the flask without using a cloth.
Anything above 65C is where you flip it from one hand to the other. Much above 70c and you drop it - quickly.
Using that as a basis I would estimate the temp at around 70 - 80C.
I have dropped one of my 8x68 cases into a glass of water immediately after firing - it didn't sizzle - so the temp is under 100C. If I had planned on doing that experiment I would have taken a thermometer to the range and measured the temperature increase of a known volume of water. I could then have calculated the case temp.
Would have to make a correction for the mass of the thermometer of course.
Ask me nicely and I might take a thermometer to the range on Saturday.
But who cares about the case when after 5 shots you can't hold the barrel and after 10 it almost burns you.
cheers edi |
| | | Posts: 222 | Location: Cape Town South Africa | Registered: 02 June 2002 |
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| quote:
Originally posted by Tombo21:
My only question is ......How hot does the brass get when you fire it? I imagine it gets much hotter. I'd reuse it.
I'm not sure how hot brass gets, but it is likely hotter than 225 F, at least temporarily.
Being a bolt-action shooter primarily, I rarely experience anything other than fairly cool brass. The reason for that is that it only takes a portion of a second for brass to transfer most of the heat it absorbs during ignition to the steel of the barrel. On the otherhand, as any shooter of autoloaders can attest, brass fired in an autoloader is damn hot, because it is almost instantly removed from the chamber and has little opportunity to conduct its heat to the barrel.
Don't believe me? Just try grabbing a case fresh from the chamber of an AR-15 and comparing its temperature to the same load fired in a Remington 700 and left in the chamber for a couple of seconds before ejecting. You will quickly notice the difference!
BTW: I'd shoot the brass without worry. |
| | | Posts: 13263 | Location: Henly, TX, USA | Registered: 04 April 2001 |
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| Ejected brass from an autoloader is hotter than ejected brass from a bolt loader perhaps from less contact time in the chamber(less time to conduct heat from the hot brass to the cooler chamber steel). But the brass probably gets a fair amount of heat tranfer from the hot and still pressurized gases flowing out both ends of the chamber/barrel as the brass is ejected. Just my opinion. |
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| No problem. I dry brass in the oven at a low setting (about 200F) all the time. It needs to be over about 450F before there's ANY annealing effect.
Michael |
| | | Posts: 3 | Location: Austin, Texas | Registered: 17 February 2003 |
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| Everybody has pretty much said I'm wrong. Maybe I am. Won't be the first time! ![[Big Grin]](images/icons/grin.gif) However, I'd still be concerned. The brass was not at 200 for a few seconds but for about 1 hour. Was it really at 200 or is that just what the stove tells you the temp is. Any baker knows that every oven is different, particularly home appliances. I shoot some BP cartridges and washing BP is recommended. But after my first experience with new brass and the oven technique, I'll never dry in an oven again. Fully one half of the cases split, down the body, on the second firing. (.38-55 Winchester, Winchester brass) Now I wash in hot soapy water, rinse in hot water, towel off and leave to dry. If there is stubborn water on the cases, I might use a hair dryer to blow dry the particular case, if it doesn't burn my hand, the brass will be fine. Maybe this is one of the few instances of some sort of OC behavior on my part but, well, this is what I do and why. If you do shoot it, I'd like to hear what happens. [ 03-13-2003, 02:49: Message edited by: Hobie ] |
| | | Posts: 2324 | Location: Staunton, VA | Registered: 05 September 2002 |
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| Hey rugeruser, I didn't see anyone mention about "how close" to the heating elements you might have had the cases. They are either On(full power) or Off. And the thermostat responds to the ambient temp in the oven.
So, if you had them too close to the heating elements, you "may" have subjected them to more heat than you(or these other folks) thought about.
I'd say to try them with Minimum Loads at first. And I'd also monitor the Case Head Expansion and Pressure Ring Expansion with 0.0001" capable Micrometers to determine if in fact they are OK.
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By the way, for those of you who use the oven, I'd also encourage you to Pre-heat the oven to your desired temp, cut-it-off, and then place your cases inside for drying. That way the distance from the cases to the heating elements is no longer an issue.
[ 03-13-2003, 03:52: Message edited by: Hot Core ] |
| | | Posts: 9920 | Location: Carolinas, USA | Registered: 22 April 2001 |
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| Hobie
Don't know what happened to your brass, but it likely wasn't the heat. Getting it too hot would cause an annealing which would soften the brass. The last failure I think you would see would be splitting. If it failed, it would likely do so by case head expansion/blown primer etc. Sounds like you either had a batch of hard brass to start with, or it was work hardened somewhere in the process. You didn't happen to make the cases from 30/30 did you? |
| | | Posts: 1238 | Location: Lexington, Kentucky, USA | Registered: 04 February 2003 |
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| I had .223 casing hit my forearm at the range while I was watching my buddy shoot and believe me, it's at least 225 degrees. I have the scar to prove it. |
| | | Posts: 648 | Location: Huskerville | Registered: 22 December 2001 |
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| quote:
Originally posted by Art S.:
You didn't happen to make the cases from 30/30 did you?
No. New, Winchester, .38-55 Winchester brass. Second loading. And please, just how is it work hardened in .38-55 dies? The case is barely belled to take the bullet and in any "case", that is NOT where the splits occur. I've tossed the brass and it is deep in my bad brass bucket or I'd send you a picture.
Interestingly, this brass was replaced by brass from the same lot which was NOT treated in this way. That brass is still in use... |
| | | Posts: 2324 | Location: Staunton, VA | Registered: 05 September 2002 |
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| quote:
Originally posted by rogerinneb:
I had .223 casing hit my forearm at the range while I was watching my buddy shoot and believe me, it's at least 225 degrees. I have the scar to prove it.
The whole gun can get quite hot in the AR-15/M-16 system because it is a direct gas action. This seems to make the brass come out hotter than other systems, say like a Contender. As if it transfers less heat to the gun before ejection. Of course it comes out sooner after firing as well. The military has several procedures to minimize the risk to the shooter (particularly left handers) from the hot brass. |
| | | Posts: 2324 | Location: Staunton, VA | Registered: 05 September 2002 |
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| quote:
Originally posted by Hot Core:
Hey rugeruser, I didn't see anyone mention about "how close" to the heating elements you might have had the cases. They are either On(full power) or Off. And the thermostat responds to the ambient temp in the oven.
Hot Core,
I didn't even think of this. I had my cases on a cookie sheet in the middle of the oven and assumed ![[Roll Eyes]](images/icons/rolleyes.gif) as we do, that others would do the same thing. An excellent point. |
| | | Posts: 2324 | Location: Staunton, VA | Registered: 05 September 2002 |
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| quote:
Originally posted by Hobie:
The whole gun can get quite hot in the AR-15/M-16 system because it is a direct gas action. This seems to make the brass come out hotter than other systems, say like a Contender. As if it transfers less heat to the gun before ejection. Of course it comes out sooner after firing as well. The military has several procedures to minimize the risk to the shooter (particularly left handers) from the hot brass.
I've been wondering about the how/why of that for a few years now. I had a bolt rifle in .223, a Contender Super 14 in .223, and a Bushmaster V-Match 16" carbine. I could fire a round, extract the case as fast as i could, and hold it in my hand, as it was only mildly warm, regardless of how much I shot (like at prairie dogs). But the AR, cripes. I could fire off a magazine worth, slow fire at a target, clear the magazine from the gun, put the gun down, and while hunting for the brass (weedy firing line), every stinkin' piece was still hot enough to just about burn my hand! Owww!
Monte |
| | | Posts: 341 | Location: Wenatchee, WA | Registered: 27 February 2002 |
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| I can see we are going to go about this in a scientific manner. We take groups of ten cases we oven roast them at different temps. then fire them in the same rifle and see what happens. Then whoever takes the data can write an article for a magazine.
Or we could keep on talking about various problems. <GGG> |
| | | Posts: 363 | Location: Missouri Ozarks, USA | Registered: 10 July 2002 |
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| Thank you for all your input - seems like I may have the beginnings of an academic treatise! In particular, proximity to the heating elements would almost certainly have a major impact on the actual temperature that the cases were exposed to - a VERY interesting thought. As it happens, the cases were in a baking dish in the middle of the oven (electric), but the thermostat is in a corner of the oven - hence, who knows what the actual temp is in the centre? However, I have received BAD news!! Mrs Rugeruser (a phenomenal and experienced cook) has just pointed out that our oven is calibrated in degrees Celsius, thus, I have been cooking my brass at something in excess of 450 degrees F. End of story. Whilst I may not have the prettiest of faces (ruggedly handsome springs to mind), I don't want to modify it at my age. I'm getting new brass!! The cost of replacing it is less than the cost of plastic surgery!! Thanks again, and as always, it is a great pleasure to be able to bounce ideas around with other members of the forum.
Rugeruser. |
| | | Posts: 1275 | Location: Sydney, New South Wales, Australia | Registered: 02 May 2002 |
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| Celsius !! now he tells us. I hope your wife has permanently banned you from her kitchen. |
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| Hobie
In answer to your question, the brass could have been work hardened in the dies if you had used them to neck up 30/30 brass. That's why I asked the question.
I still believe that your case failures were caused by something other than heat, if they were only heated to 225 deg (Farenheit not Celsius!!). If they were ruined by heat, they would have been soft, not brittle.
Other possibilities? Perhaps a chemical reaction caused by trace cleaning or polishing compounds which was accelerated by the increased temperature. While 225 is not critical from a metalurgical standpoint, it is a big increas as far as reactions are concerned. There are a lot of chemical interactions with metal. One of the most serious is chloride induced stress cracking of some stainless steels for instance. It's possible that something in the cleaning chemicals remained and reacted at this temperature. |
| | | Posts: 1238 | Location: Lexington, Kentucky, USA | Registered: 04 February 2003 |
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| Art S , perhaps the worst chemical for stress corrosion cracking of brass is ammonia compounds. Keep bore cleaners off the brass.Ammonia is also generated during thunderstorms. Factories anneal case necks to prevent cracking during storage. |
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