Disclaimer: I am not an engineer, nor do I play one on tv.

Instead of all the work which goes into producing a steel barrel, why not produce a bored tube which will accept a ceramic liner?
A liner could be molded with the rifling cast in, eliminating the boring procedure and reducing costs. Ths article (link removed by Cliff Pennock per request of website linked to) suggests to me that the pressure and heat requirements can be easily met with ceramics. From the article:

quote In particular, TaC is thought to have the highest melting temperature of any material at 3997°C.

That material more than meets the temperature requirements.

quote When second phases such as SiC or MoSi2 are present in volume fractions of 10% or higher, room strengths in the range of 800 MPa to 1000 MPa or higher have been reported.

Comments I have read on several websites indicate maximum pressures for 7.62 at 360 Mpa, so 800 should be a good safety margin.

quote Traditionally, borides and boride-based particulate composites have been densified by hot pressing at temperatures of 2000°C or higher.

Cost of producing a material like this would certainly be much higher than steel ( 2000C=3632F That hot? No, just don't take me long to look at a horseshoe.). I imagine that somewhere in all the choices the right material strength / cost balance could be found. As for production temperature, don't try this at home. The wife's oven won't make it.

The barrel blank still has to have a straight bore, of course. That requirement alone may make the exercise pointless.

Having absolutely no knowledge on this subject, I'll just bump it along and hope someone else has a qualified opinion.

Bump.

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Ron
"The budget should be balanced, the Treasury should be refilled, public debt should be reduced, the arrogance of officialdom should be tempered and controlled, and the assistance to foreign lands should be curtailed, lest Rome become bankrupt. People must again learn to work instead of living on public assistance." - Cicero , 55 BC. So, evidently we've learned nothing in the past 2,000+ years.

Melanie’s dad had a shotgun with a fiberglass barrel, that’s right a fiberglass barrel. I think it had a very thin steel liner in it but it was so much lighter than even my old Mossberg riot gun. So it is possible to lighten up the weight by using different materials, it has already been done with other materials.

I would have to look at it for the make but I know it is a fiberglass barrel.

Steve

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Technology is great when it works,
and one big pain in the ass when it doesn't



Detroit iron rules all the rest are just toys.

For every action there is an opposite and equal reaction. Plain ole physics.
While the bullet is traveling down the barrel it imparts a twisting motion to the barrel. That is because the barrel is causing a twisting motion to the bullet. The bullet also causes the barrel to bulge microscopically since you are passing a slightly larger object into the barrel to shape the rifling on the bullet. There is also a whipping motion imparted.
In my opinion, and I'm not an engineer, all those would cause the ceramic to break down.
About rifling in the ceramic: ceramic is essentially a mud that needs to be heated to make it solid. So casting in the rifling would be very easy.

[This message has been edited by n7vrz (edited 03-05-2013).]

quote Originally posted by heybjorn: ... why not produce a bored tube which will accept a ceramic liner?

Ceramics are materials that are less well understood than metals and plastics, and I am not a ceramics engineer. In general, however, ceramics 1) have high strength in compression but relatively low strength in tension, 2) are very hard and abrasion resistant, 3) are very brittle, and as a result 4) are susceptible to cracking under mechanical or thermal stress.

A better strategy might be to "plate" the inside of a steel barrel (to provide tensile support) with a layer of ceramic a few atoms thick. How to achieve tight bonding between steel and ceramic would be challenging. Even then, corrosion over the long term between the steel bore and a ceramic layer might be a problem. I'm sure the experts have thought about this already, and have probably even tested the idea. Of course, new materials and new manufacturing techniques always bring new possibilities.

[This message has been edited by Marvin McInnis (edited 03-05-2013).]

wouldnt it wear much quicker?

I would guess with faster wear, this would also make forensic ballistics much more difficult, if the wear patterns changed within 5-10 shots.
and, any chance of chunks breaking loose & jamming the bore - YIKES

[This message has been edited by Pyrthian (edited 03-05-2013).]

Ceramics tend to be more brittle than metals. I would think that would be the weakness.
Heat and pressure loads aren't the whole picture - there's impulse (shock) loads as well as the previously mentioned torque on the barrel from the rifling, etc.

I'm not saying it can't work, but I think the problem is much more complicated than it may seem on the surface. Sounds like an interesting idea, though.

Marvin, give me your thoughts, please. At the instant of the explosion, would the force on the barrel be compression, radiating more or less equally, or shearing, with the gas pressure decreasing
at every measurable segment of an inch, until it drops off to a level which makes no difference?

I hadn't considered corrosion.

quote Originally posted by Pyrthian: wouldnt it wear much quicker?

As Marvin said, ceramics are hard and abrasion resistant, which makes me think wear wouldn't be a problem. Pieces breaking off, maybe.

[This message has been edited by heybjorn (edited 03-05-2013).]

Do a search for nano teck ceramic coating.

[This message has been edited by maryjane (edited 03-05-2013).]

Thanks, Don. I should have searched for ceramic rifle barrel before asking the question.

It has been done.

There was some talk years ago of an attempt to produce a very long range artillery barrel from ceramics. I don't remember how it worked out.

quote Originally posted by Formula88: Heat and pressure loads aren't the whole picture - there's impulse (shock) loads as well as the previously mentioned torque on the barrel from the rifling, etc.

I have an engineer friend who does design analysis on such things, and I remember him saying that he had recently looked into it and the angular acceleration of a ballistic projectile in a rifled barrel is equivalent to more than 6,000 G.

[This message has been edited by Marvin McInnis (edited 03-06-2013).]

http://www.thefirearmblog.c...ectable-plastic-gun/

This actually brings up an interesting possibility- powdered metal barrels. The benefit of that is they can (and do) blend metals in combinations. They could mix metals that would provide strength and inherent lubrication.

If you aren't familiar with powdered metals, it's very cool.

What's wrong with steel? It wears well and has the needed mass (weight). You need some weight to balance the recoil and you can change the weight easier by changing the composition of the frame (i.e. Glock). Why reinvent the wheel?

quote Originally posted by Monkeyman: Why reinvent the wheel?

Ideas like that certainly come from television, and will be the end of society. Why, that kind thinking may end the horse and buggy days!

Nobody has mentioned toxicity.

We use ceramic materials (specifically, beryllium oxide) for the construction of vacuum tubes (still in use in high power radio equipment), heat sinks, and various other electronic devices. It has no conductivity of electric current, high conductivity of heat, and is, apparently, transparent to radio waves.
It also pretty nasty if it gets chipped. The particles/dust created are carcinogenic, and can produce inflamation of the lungs or other organs.

Not saying that all ceramics are toxic, and obviously BeO would not be used for rifle barrels.
But toxicity is another consideration.

Ceramic Toxicity sure sounds like a great name for a band. So does Nasty If Chipped.

quote Originally posted by heybjorn: At the instant of the explosion, would the force on the barrel be compression ...

The forces in the pressurized segment of the barrel would be almost entirely tension. Think of pressurizing an old-fashioned wooden barrel full of water (or your favorite beverage) ... it's the job of the steel bands (loaded in pure tension) to resist the pressure loading and keep the barrel together.

[This message has been edited by Marvin McInnis (edited 03-07-2013).]

I see what you mean. Thanks.

a rabbit trail if you're looking for one...
Do bullets make a small sonic boom?
I mean the ones that break 762 mph or so...

[This message has been edited by 2.5 (edited 03-07-2013).]

quote Originally posted by Raydar: Nobody has mentioned toxicity. We use ceramic materials (specifically, beryllium oxide) for the construction of vacuum tubes (still in use in high power radio equipment), heat sinks, and various other electronic devices. It has no conductivity of electric current, high conductivity of heat, and is, apparently, transparent to radio waves. It also pretty nasty if it gets chipped. The particles/dust created are carcinogenic, and can produce inflamation of the lungs or other organs. Not saying that all ceramics are toxic, and obviously BeO would not be used for rifle barrels. But toxicity is another consideration.

Yes, beryllium is extremely toxic. But every other ceramic I've come across is non-toxic, and extremely inert.

quote Originally posted by 2.5: Do bullets make a small sonic boom?

Yes. Subsonic bullets are much quieter.

FWIW, the crack of a whip is the sound of the shock wave produced when its tip exceeds Mach 1.

[This message has been edited by Marvin McInnis (edited 03-07-2013).]