I was showing off my 1880's vintage hammer gun recently and I had someone comment that he would never shoot something that old because he would be afraid the steel would be too brittle. Even though my gun is in wonderful shape and that isn't something I worry about, I can understand his retiscence. At what point, if ever, would steel barrels become brittle enough to make shooting them unsafe, no matter their condition?

I doubt it's a problem. I wouldn't be surprised if the metal changes. However, I doubt they become dangerous.

The Brits send old, damascus bbled doubles through the proof house all the time. These guns pass all the time.

If there was a problem, the proofing process would reveal it and the resale of these guns would be banned in the UK.

I say load it with the appropriate loads and shoot away.

OWD

It's called "fatigueing", and it usually takes thousands of cycles.

the solder holding barrels to rib(s) will surely fail first.

Mark et al: Remington was the defendant in a major lawsuit over this issue maybe 15 years ago, and lost. Prosecution was able to convince a jury that their metallurgy was deficient in, I think, their 870 barrels from the 60s and 70s. Their allegation involved the embrittlement issue. That is slightly different, in that it was not age related. This information I learned in a class that I took at our junior college in metallurgy, taught by a nuclear physicist who was the expert witness for the prosecution. I could not find my notes from the class so this is from recollection.

I know nothing of metalurgy so I speak only of the risks I'm willing to take based on the experience of many shooters in Europe and the US.

I have a 16 gauge Joseph Lang built in 1866 with replacement damascus barrels by James Woodward most likely from 1872 or earlier.

I have a 12 gauge J&W Tolley with the original damascus barrels that dates between 1887 and 1894.

The Woodward barrels on the Lang were reproofed at 900 BAR in 1990. The Tolley was reproofed at 850 BAR in 1989. The Birmingham Proof House obviously had no concern about the barrels because they passed both view and proof firing and they applied the marks indicating reproof.

I shoot both of these guns and have no concern that the barrels will fail - provided, of course, that I shoot appropriate low pressure loads.

Age (chronological time) embrittlement is not an issue with plain carbon steels such as used in older fluid compressed steel barrels, twist, and damascus. Fatigue embrittlement would require millions of cycles at the level of strain which barrels in good condition experience with firing.

If Remington was using some alloy other than plain carbon steel, and I expect they were, this would be a separate issue.

Good answer Rocket. I knew you'd come through.
Is there any reason high mileage barrels wouldn't exhibit strain hardening?

Embrittlement of barrel steel from age is an old wive's tale. Rocketman knows of what he speaks.

Short answer, probably Not.

Long answer, A court of Law has no realtionship to Physics or Metalurgy, so we will dismiss the Rem suit.
For fluid steel as correctly Posted as long as the stress applied and resulting strain are within the Plastic Deformation limits, the barrel will always return to its original dimensions and be fully functional for the next cycle. Some steels have a Theortical Limit below which they do not exhibit fatigue. BUT and this is the big BUT, turn of the century metalurgy was an almost archmical process with not much actually understood about why things happen, so your barrel would be judged on an individual basis. In other words if it doesn't fail its good, if it does fail its not good. The movements in the steel lattice structure are only visible under Transmission Electron Microscopy and require a destructive examine, i.e a slice of the barrel.
So basically, newly manufactured gun barrels are immune from fatigue and brittle failure but for an older gun, who really knows. If truly in doubt, that is why the Brits Re-Proof older firearms.-Dick

As has been posted by others above, the short answer is 'No'. Old barrels may become unsound because they have rusted, because the lumps come loose or the ribs come detached or because they have been lapped too many times and are consequently thin. Obstructions may cause the tubes to bulge. All these things can be checked for.

Otherwise, damascus barrels are sound regardless of age. I spent the weekend shooting clays with a Manton double flintlock with damascus barrels, loaded exactly as Manton would have recommended when it was new. Shot 50 clays no problem. Likewise the 1840 Lancaster percussion muzzle loader we used the same way for 100 clays and the 1868 Sylven breech loader I use all the time.

I re-proof damascus barrelled guns regularly at the London Proof House and the Birmingham proof house. I have yet to have one fail nitro proof.

Could not the wall of a barrel act as a spring? Yes they flex .
Springs fail,at some point,depends on the certified alloy/temper.
You wont know wher this point is,but...
This is where your minimum wall thickness comes in to play.
The stiffer the better in an old gun.

Quality maker,good wall thickness,plus low pressure cream puff loads,equals no problemo.

What about 7/8 oz cartridges at < 6500 psi in a 2 3/4" 12 bore gun with minimum walls of .018 that passed reproof sometime in the last, say, 20 years? No go? Thanks for any thoughts. EG

As noted by dick and my first post, the number of strain cycles to a fatigue failure (strain embrittlement) would be in the millions, most likely many millions, for a shotgun barrel during sevice use. If this were a real issue, we would have documented examples and guns would be equipped with firing cycle counters.

Imagine the number of strain cycles suspension bridge cables go through - yet, they don't fll down from cable embrittlement.

Thank you everyone for your replies. This is exactly the kind of information I was looking for.

With those old guns it's always the next shot that could get you.....bOOm....you never know.

The ductility of the steel was determined during the blending of the constituent metals (and other stuff) at the mill.
The ductility of the tube was changed and refined at the rolling mill by external pressure during rolling.
Boring the tube does not change the ductility of the steel.
The ductility of the tube was proved in testing, pre-sale by the manufacturer.
Unless you remove material from the as delivered barrels you have the same formula and ductility forever.
Firing millions of shells would slowly change the ductility, but, everything else would go into the trash before it happened.
It's a non issue for any shotgun tube close to original wall thickness, using the loads it was designed for.

Now, if a dent or bulge enters the picture, because the coefficient of elasticity was exceeded in that area, metallurgical changes have occurred there.

In all my reading, I have never heard of heat being applied to a dent repair, so, I don't believe the matrix of the steel is returned to original in a dent repair. But I also believe that the loss of ductility around the repaired dent is small enough that the lifespan of the tube while shortened, is still decades in excess of every other part of a shotgun.
Again, where the dent occurs being more important than the change in ductility due to the gigantic number of cycles required to fracture unmolested steel tubes.

The proof is in the the thousands, perhaps millions, of dents having been removed in the traditional fashion, not including heat.

I threw in the dent segue, because dents (and bulges) do change the lattice of the steel around them. And no one should forget that.

Boy! If I had a nickel for every time a woman asked me this question! Oh, I see what you mean..... Anyway, I have heard people say they don't want to cock old guns because the springs might be brittle and break. But I don't know if this is true or not. I have had a garage door spring snap from time to time after it gets old. But barrels? I don't know about that. I have seen a lot of old guns fire after they were several decades old. (She said that, too.)

Spring steel having been hardened and tempered is under perpetual stress. I cannot speak with any authority on the subject but having seen a lot of springs near 200 years old many have lost their strength. Do the molecules in the steel slowly revert to their relaxed state? Would it be the same principle as glass slowly reverting to its prior nature?

Picture this Joe,
I should point out it isn't a perfect illustration, but it is pretty current theory.
You have a round wire bird cage with a parakeet sitting in it on it's swing. You nail the floor of the cage to a plank, and affix a bar to the top hanger. Now you twist the bird cage (with the bird inside) clockwise or counter, it's your choice. You will see the cage get smaller in height. The wires will be getting closer together, and the flapping bird ever more cramped.
You would confirm via the birds failure to keep singing, and very likely to begin squawking, that the state of the birdcage is an undesireable condition. And, you would find out apon letting go of the top bar, that the cage (and bird) wish to return to their prior state.
This holiday analogue is approximately the way a steel matrix (the cage) and the carbon atoms within it's confines (the parakeet)wish life to be.
They can exist under perpetual stress, but they don't like it.

Firing millions of rounds are kinda like tapping, or beating on the top of the twisted cage. It might take a long time, but sooner or later, a wire is going to break. One wire probably makes no difference to the retension of the parakeet. Half the wires? and the twist of the cage either frees, or kills the parakeet.
But to steal a line from Tolkein, "it takes a loooong time".

This twisted cage idea comes from thin film chemistry and metallurgy. It's one explanation for how the structure of molecules can attain ( atomic level)stackings that cannot be explained via group theory models.

I have no doubt that my theoretical chemistry interests are umm, a little ways away from the mainstream of doublegun ownership.
But just to say I'm just like everyone else, I want my shotguns to go bang everytime I want them to, and I want it to occur safely. And of course for everyone else as well.
I think I'm gonna turn off the nerd switch now, and eat some poorly prepared northern barbecue, and drink a great deal of very cold cheap beer.
Happy Memorial Day everyone.

I've heard they once used parakeets in mines to warn of poison gases but I've never heard of using one to warn of possible barrel failure....might need to get me one.