unbreeched 20ga. shotgun barrels

[mlbrant]

does anyone know where i can purchase an unbreeched 20 ga. shotgun barrel? numrich arms used to sale them but these barrels are no longer sold by them.
i need it for making a flintlock smoothbore.
thank you :hmm: :hmm:

 

[Keb]

What dimensions? I have a few 20 ga. bbls. 2 @ 34 3/4" & 1 @ 36" made from DOM CRS. They have breech plugs installed but could easily be backed out.

 

[rabjr]

Track of the Wolf sells them. I believe they are 36" or 42" and they will cut and crown in between if you want.

 

[Zonie]

Folks should know that DOM stands for "Drawn Over Mandrel".
Tubing with this designation is NOT SEAMLESS TUBING.

It is rolled steel, welded with an electric arc welder and it does not have the strength of true seamless tubing.

The drawing process smooths out the weld joint and sizes the tubing so that it will work with the standard tube fittings commonly used.

DOM tubing is useful for low and medium pressure applications that do not have pressure spikes where the pressure goes from zero to 3,000+ psi in milliseconds.
A gun barrel may go from zero to 15,000 psi almost instantaneously.

I do not recommend using any DOM tubing for any kind of a gun barrel under any condition.

 

[mlbrant]

thanks everyone for the help! :v however, i am talking about one of the inexpensive belgium barrels that numrich arms used to carry or one like it -not a modern muzzleloading smoothbore barrel.

 

[Bubba45]

They are still on there but it will take some searching as they reconstructed the site ! :cursing:

 

[Keb]

Uh... Can you tell me how old barrels were made? Were they not made from flat stock heated & formed over a mandrel then hammer welded?

How did any of our ancestors survive?

 

[Zonie]

They were made from iron, not steel and when done by someone thoroughly knowledgeable of hammer welding iron can produce a good weld that doesn't have the "heat affected zone" associated with arc welding steel.

I might add that during the times that hammer welded wrought iron barrels were made they were known to fail.
More than one book documents people who were missing parts of their hands, etc because their barrel burst and these bursts happened on barrels that were very likely "proofed".
Proofing of these hammer welded wrought iron barrels was considered to be a necessary part of building a barrel at the time.

 

[Keb]

well, I dont know where you got your information but 3000psi is slightly different than what I have read on DOM.
"Mild steel ( 1020 ), welded seam ( ERS) mechanical tubing would have a yield strength of around 40,000psi
DOM tubing ( which is usually made from 1020 and has a welded seam ) , due to the additional cold working could have a yield strength around 70,000psi."
Using these figures & a burst formula, DOM will rupture @ 33,800psi.

 

[paulvallandigham]

Apples and Oranges, KEB. Jim will answer in better terms than I can, but you are overlooking the reference in his post to INSTANT pressure over 3,000 psi. The figures you are reading are for maximum pressure created over time by raising the pressure slowly in the pipe.

The Arc welding actually weakens the steel, by burning out some of the carbon that gives the steel its strength, right at the seams. :nono: :shocked2:

Tube steel can be made by pushing a Broach through a block of steel, to form the inner bore diameter. It has not been necessary to use flat stock, formed over a mandrill and butt welded to make barrels, in almost 100 years. The method persists for pipe used for water, and gas lines.

Barrels made the modern way are more expensive, but that is because they are designed to handle the Instant High pressure applied to them when gunpowder- Black, or smokeless- is burned in them. There are different barrel steels used for the higher pressured Smokeless pistol and rifle barrels, than we use for Black Powder barrels. It has to do with the pressure curve difference between the two kinds of powder.

 

[Keb]

OK but I've seen no documentation yet. Anyone can say what ever they want to say. I'm proof of that. But without any documentation it is all meaningless unless someone has other motives or just wants to look like they know what they are talking about or passing off information 2nd or 3rd hand. Can you prove your statements? Have you ran any tests on DOM? If so, please pass this information along. Real life barrel proofing (double loads) without failure is a good layman test. I can vouch for that. But, you don't have to take my word for it. Just get some DOM, breech it and blast away.

Now, pressure "spike" or breech pressure at time of ignition has many variables like bore size, powder amount, powder grain size, rifling & rate of twist or smooth bore, length of barrel, etc. Failure has to do with tensile strength, OD, wall thickness, material, etc. There are a lot of variables and to just make an undocumented statement that DOM is not safe is misleading. Run some tests on DOM/ CRS then get back to me with your results. In the mean time, you can send flowers to the local funeral home in the town I live in if you like.

 

[Zonie]

Keb:
If you don't wish to believe me, that's fine.
This is not the place to present my credentials or industrial background.

I would suggest that rather than asking me for information that documents my comments about the use of DOM tubing you should do your own investigation. That way you will be more apt to believe the data.

Better yet, you should consult with a good mechanical or materials engineer familiar with the properties and proper application of steel.

As for your calculation above for a DOM rupture strength, without knowing the wall thickness I cannot verify it but I will say that when dealing with gun barrels Yield and Tensile strengths are not all that matters.

As you mentioned Cold working (like drawing steel thru dies and over mandrels) does increase the tensile strength and yield strength but just as importantly it will decrease the steels ductility and make the material more brittle.

This loss of ductility which is reflected in the materials Elongation properties can range as much as a 12 percent loss in a low carbon steel by cold working it.

A loss of ductility can lead to unpredictable failures especially when used in a gun barrel.

As a side note, during the Civil War the Army did a study to determine the minimum wall thickness needed for a rifled musket.
After much testing they decided that the minimum wall needed was .200 at the breech.
No, I'm not going to dig out the source of this information. You'll just have to trust me.

 

[Keb]

Zonie said:
If you don't wish to believe me, that's fine.
This is not the place to present my credentials or industrial background.

I would think it is the perfect place to present your credentials & background. How do you expect to convince me you know what you're talking about without that?

Zonie said:

I do not recommend using any DOM tubing for any kind of a gun barrel under any condition.

Again, upon what facts do you base this statement on?

OK. As you know, it's hard to change someone's mind if they already have their mind made up. Stating opinions one way or the other is just an open invitation to an argument. I have read both pros & cons when it comes to using DOM. Some of it may have been true and some of it manure. I have successfully used DOM as smooth bored BP barrels without incident. Of course, there is an element of risk in confining any explosive material in any type of container. It, IMHO, boils down to the person using a muzzle loader. Would you agree that any barrel will or could rupture if used improperly?
This is like the bevel up/ bevel down controversy.
Some will disagree.
Some will repeat what someone else told them on the subject without any past experience.
Some will quote a long time "expert" just because they believe whatever comes out of their mouth is gospel.
I will continue to use DOM as smoothbore barrels. I will not try to convince anyone else they are safe or unsafe for a profit. I will sell a gun with a DOM barrel and will be up front about it.

 

[Zonie]

Zonie said:
If you don't wish to believe me, that's fine.
This is not the place to present my credentials or industrial background.

I would think it is the perfect place to present your credentials & background. How do you expect to convince me you know what you're talking about without that?

OK. Those not interested may not want to read thru all of this and I can't say I would blame you. :grin:

My College education was in Mechanical Design and Secondary Education, Industrial Arts.
I only officially used my Education degree to teach some College level classes on Geometric Tolerancing and Design.

While I was still in College I hired into a company that produces jet engines, Auxiliary Power Units which are gas turbine engines that supply starting, ground power and emergency in flight power on commercial and military aircraft and ground applications, and control systems.

I started my 40 year career in Tool Design designing special cutting tools, jigs, holding fixtures, weld fixtures, form/piercing dies and special gages, Electrochemical (ECM) and Electrical Discharge (EDM) tooling.
I also designed special machines required to produce hardware for which commonly available machines were not made.
I also designed many special gaging machines which measure multiple features for turbine and compressor blades (bow, twist, lean, displacement and other critical dimensions).

I then worked as a Quality Assurance (Quality Control) Engineer for several years specializing in Engineering Design review for specifications, inspect-ability and Geometric Tolerancing.

I moved into Engineering Design in the APU branch of the company designing hardware and systems for Military applications, both ground and airborne.
I've worked on the APU designs for the B1, F15, F18 and F22 and others.

I was promoted to Lead Designer for the (then new) Airbus A330 and 340 Auxiliary Power Unit.
Following this I was the Lead Designer for the Boeing 777 APU.

With these programs I was responsible for system compatibility and interfaces as well as for the design of all things which goes into or onto the Auxiliary Power Units.

Following this I became the Principal Designer for all of the Large Commercial APU's made by our company. These are used on the Boeing 720, 757, 767, 777 and the Airbus A320, A330 and A340.

In this position no part of any of the APU's I was responsible for could be changed without my approval. All proposed designs required my approval before they could be finalized.

All problems with these engines, whether it was a functionality or repair-ability issue was directed to me for resolution.
I also served as a consultant on all new and proposed APUs (both large and small) for applications coming down the pike.

While in Engineering Design I was expected to have a through knowledge of manufacturing, inspection, stress analysis, material properties, rotor dynamics and basic thermodynamics.

We had many Engineers who were specialists at all of these for running complex stress analysis, materials analysis, bearing analysis, controls analysis, dynamic analysis etc, and these people would analyze my proposed designs.

I often did the simpler calculations required for these designs so that they would not require major revisions following these more complex and detailed studies by the experts.
(May I say I have worked with some of the best of these people in the world.)

Although I have extensively used Computer-Vision and Catia computer design in 2D and 3D and although these systems both are useful for doing stress and vibration analysis, the simpler stress and thermodynamic calculations were often easier to do by hand hence, my knowledge of these areas is not limited.

I hope I didn't come off sounding like the Great Someone here but you asked for my background.

As for DOM tubing, I am not totally against using it for a gun barrel.
There are some alloys available which have material properties high enough that they can overcome the manufacturing weaknesses of the process. These alloys are not low carbon steel (1018, 1020 etc.).
I must point out that even these high strength alloys in their annealed condition are no better than 1018 unless they are properly heat treated to bring out their inherent strengths.

Have a good one!

 

[tg]

All I have gathered from this is that someone here is qualified to start a gun building shop in India.

 

[peter hawbaker]

Got a good chuckle out of that one, Thanks TG !!

 

[Keb]

Thank you. I know that was a lot of typing and maybe why you didn't want to go into it.
I am still a little foggy on why you posted not to use DOM though.

an aside to tg.
Do you really think Zonie will be moving to India soon? :/

 

[Zonie]

No, I'm not moving to India.

When you say, "I am still a little foggy on why you posted not to use DOM though." and, "I will sell a gun with a DOM barrel and will be up front about it." it is somewhat worrisome.

The average buyer doesn't understand the potential hazard of using low carbon steel DOM tubing for a gun barrel any better than the seller does. Perhaps they know even less.

 

[tg]

"Perhaps they know even less."

Been lots of that around here lately :idunno:

No, Calcutta Keb, I think Zonie will stay local we would miss him to much if he left us. :grin:

 

[ohio ramrod]

I worked for a company (paramount machine ) that made aircraft hydraulics. And also for North American Rockwell. And we NEVER used DOM tubing for aircraft hydraulics, only seamless!. Why ? Because even if a sample lot of DOM passed all tests. The next piece might have a "weak spot". All welds are not created equal! :hmm: Would I hold a piece of DOM in my hand with a charge of powder in it? NEVER! :surrender: But then my opinion is free and you get what you pay for! :hmm: