doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Do barrels get brittle with age?

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.