Seeking Data on What Temperature Will Dangerously Soften Gun Metal

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Yes, as a general rule, any firearm that has been in a fire is presumed unsafe to shoot.

I am looking for factual information preferably with a cited reference about what temperature will definitely soften or degrade the metal in guns such that it is no longer safe too shoot. I am interested in this information for regular carbon steel and for stainless steel if there is a difference between the two. For example if a gun barrel or cylinder is heated to 300 degrees for five or ten minutes will that render it unsafe? If not is 400 or 500 degrees the upper limit? In vain have I searched the internet. I would greatly appreciate anyone who can refer me to data on this issue.
 
Here's some info for 416 stainless:


Scaling resistance of grade 416 steels under intermittent conditions can be extended up to 760°C, and up to 675°C under continuous operations. Considering the sustainability of mechanical properties, 416 steels should not be employed at temperatures greater than the standard tempering temperatures. [/QOUTE]

https://www.azom.com/article.aspx?ArticleID=971

I think as a general rule, you're probably not going to get the metal in a firearm hot enough to degrade it just by shooting it. That is unless you have a full-auto firearm.
 
I think a firearm burned to the point it is unsafe to shoot would likely be unable to shoot. All wood or plastic would be gone and springs also are negatively effected by high temperatures.
 
In vain have I searched the internet. . .
Because there's no such thing as 'gun metal'. There are hundreds of specific alloys, many of which can be heat treated to several different configurations, which may or may not be appreciably altered by various times at temperature. If you want to understand all of the caveats, start with a 2 year degree in metallurgy, and then somehow motivate the manufacturers to disclose their alloy and heat treat specs.

In general, if the springs aren't softened then the rest of the frame/barrel/cylinder/slide is probably ok. All bets are off for non-ferrous alloys, or boundary-pushing cases (ie Ruger's thin-walled .454 cylinders, S&W ultra-light 44Mag, etc).

The liability implication of answering your question is too great; no one with the necessary information can afford to do so. It's annoying, I know; I design a complex product that you use every day and I get this sort of question frequently. I could answer the customer with data, and be right, and still lose! All it takes is one accident (theirs, not mine), and my answer turns into a $100 million liability.

Edit: the solution, for a manufacturer, is simple: Publish the standard specification/product description, and when a customer asks if their (whatever) is ok even though they've abused it, say 'No' and sell them a new one. 'Probably' just doesn't cut it.
 
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If your answer turns into a liability, should you/your company be doing what you are doing in the first place?

Or is that just opening up a whole new world of complication?
 
It is very simple. All you need to know is the alloy of each critical part and the working hardness of each, Then look up the draw temperature for that hardness of that alloy. Don't shoot a gun that got hotter than the lowest such temperature. Hatcher has the heat treatment regimen for the various materials in 1903 Springfields, but that is just an example, nobody uses "ordnance steel" or low nickel alloy any more.

As said, the rule of thumb is the springs. They are a pretty narrow range of material and temper, AND they are internal. So if the springs are softened, then the whole action was at or above the annealing temperature. Stocks/grips charred or melted near the metal is another disqualifier. Near the metal, I knew a guy who had stood his Savage too near the campfire and scorched the butt. No effect on the metalwork.

There was a shop here that used to do a steady business in house fire guns. Refinishing a gun with the stock peeled and the steel rusted from smoke and water was not a problem for them. But then there was the stack of wrecks in the corner that had been judged too bad to fix. Too soaked and rusted to be worth it, maybe rusted bad enough to thin the metal, those obviously flame damaged,

In the fire of the Incident of 2010, my long guns out of the safe were smoke and water damaged. None were terribly bad and all were refinished by a different shop, the one above having closed years ago, and my homeowners insurance even paid the $7000.
 
Agree with the above. Springs are the most hardenable steel in the gun, and therefore the first things affected by climbing temperatures re-tempering the steel. Maybe 500F? Barrels and receivers of carbon steel i would not remotely worry below 700F. They are not hard enough to be tempered below 700.
 
There are various "meltdown" videos on YT where firearms are shot full auto until they are compromised. Some may even have some temp data. If you are looking for trusted sources, then you will need to find a metallurgy book with tables/charts that include temp and yield strength for the specific alloys (and heat treatments) in question. This information is most likely not free.
 
Maybe I'm a little safety conscious but if a gun had any charring,melting or discoloration I would de milled it as a wall hanger. Do you want a potential grenade next to your face when you pull the trigger? Or others down the road. No thanks.
 
No, just a difference in degree.
Tempering brings fully hardened steel to reduced hardness and greater toughness.
Annealing just takes it all the way to minimum hardness for the alloy.
 
Engineer hat on here. Exactly as edwardware said, there is no such thing as "gun metal."
Get yourself a big black book (https://www.bookdepository.com/Machinerys-Handbook-Christopher-J.-McCauley/9780831130916) and tuck in.

"re-tempering the steel".

Wouldn't the proper term be "annealing"?

No. Annealing is "relieving stresses and normalising the material" - the piece is heated to it's (alloy specific) critical temperature and cooled s.l.o.w.l.y.

Tempering is done after hardening to make a piece less brittle.

To "re-temper" a piece you would anneal it (remove any "heat treatment"), then heat to bright red and quench to glass-hard (or as hard as the steel will take), then heat/soak at a lower temperature (alloy specific) and quench.

Any firearm *could* be re-tempered after a fire event, but cost vs time, probably not very practical.
 
Probably more relevant, is that any steel that's been to heat treat temps is likely going to warp.
 
I can’t help but wonder what the manufacturers would say if you asked them.

Personally I believe this is an impossible question to answer. Their are so many different types of metal in one firearms and they do such different jobs.

For instance I’ve seen AK barrels literally glowing hot (no idea the temp) for different lengths of time some multiple times, some dunked in a 5 gallon bucket of water to cool it off and keep shooting. And I’ve never seen the metal itself fail.
That said, nearly any spring heated to glowing isn’t likely to perform correctly, if at all, but that’s still not not necessarily unsafe.

Still, if you heat up the guide rod assembly in the earlier mentioned AK that hot, well, I wouldn’t shoot it. You could have a real bad day if it failed.
 
Dear All,

Thank you very much for your detailed answers, I greatly appreciate them. I realize this is a far more complicated question that I originally anticipated and now I understand why there isn't an easy answer on the internet.

edwardware I had not thought about the liability issues involved in answering the question I posed. Thank you for pointing this out.

Scooter22 yes, of course, you are correct. Any gun where it is possible that it has been in a fire has to be deactivated so it cannot be fired.
 
Dear All,

Thank you very much for your detailed answers, I greatly appreciate them. I realize this is a far more complicated question that I originally anticipated and now I understand why there isn't an easy answer on the internet.

edwardware I had not thought about the liability issues involved in answering the question I posed. Thank you for pointing this out.

Scooter22 yes, of course, you are correct. Any gun where it is possible that it has been in a fire has to be deactivated so it cannot be fired.

Actually I should have clarified "house fire". If a firearm has smoke damage only and was not anywhere near the heat of the fire I would think those can be salvaged. Such as if the fire is contained to one room, floor or area where the guns weren't exposed to heat just smoke. Thats pretty obvious of the surroundings where the guns were stored.
 
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