Regarding DOM/Seamless Barrels...

[ahil925]

Hello all,
Hate to make my second post here a fight starter, but I have questions regarding DOM tubing for smoothbore barrels. I understand that there are many here that feel that its unsafe to use and that there are probably as many here that feel just fine using it and have for a long while.

My question is, to those of you who have barrels made of the stuff, what grade of steel is it? Also, if you made the barrel yourself, where did you purchase it?

Currently I have a Green Mountain 0.45 cal "Special projects" (read: recycled Knight Disc) barrel that I'm planning to build on, but I'm also considering making a ~0.45 - 0.50 cal smoothbore aimed more towards small game and fowl.

 

[BillinOregon]

Ahil: Good luck on this one. You'll hear diametrically opposed opinions from very knowledgeable folks, and at the end of the day will have to make your own call. That said, high quality American made tubing of known specs is a different breed of horse than God-knows-what tubing from India.
Like you avatar!

 

[ApprenticeBuilder]

diametrically opposed

Nice !!!

Not many would recognize that term, much less be able to use it verbaly or professionaly

:hatsoff:

 

[Old40Rod]

I've never done it myself and I don't have an opinion one way or another on the subject.

But I would point out that it is important to understand the difference between the following questions -- "is it safe to do?" and "has anyone done it without getting hurt?" I don't know, but your inquiry seems more like the latter than the former. There may be many reasons why people may have been able to pull off doing something without injury that is otherwise generally hazardous to do. Mebbe they are just lucky :wink:

 

[iammarkjones]

I cannot answer if it is safe or not but I have a piece of 1" OD / .625 ID chucked in the lathe right now. I plan to install a breech plug and do a bit of documented proof testing. Keep in mind that this is certified USA 4140 seamless DOM tube from a respectable ISO 9002:2008 manufacturer. I plan to post my results on this forum. I have developed a remote ignition system to prevent those nasty shrapnel injuries.

 

[Erzulis boat]

This current "smoothbore" craze.........

This is the year 2011, you can get a real, honest to God barrel at the drop of a hat, either by purchasing, or making your own if you have the tools.

Barrels with correct historical profiles, made by folks that do it every day are shockingly inexpensive.

If DOM "works"...........then who cares? It's like the guys that are proud as can be that they weld with a coathanger.....real welding rod is pennies a pound and makes 100% better welds. This is just an example.

This is just my opinion of course :grin:

 

[gmarc]

A safety lanyard might be a good idea. 4140 DOM may or may not be heat treated as real gun barrel might. DOM 4140 is most often used in automotive roll-cages and is very tough, but I don't know if it has the type of toughness needed for a pressure-vessel. You might not want to go thinner than 12 ga. wall.

Usually, this tubing is annealed in anticipation of welding and is not hardened.

Bear in mind that real barrels are not expensive.

 

[jerrywh]

I made about three or four barrels from so called shelby seamless steel tubing. Never had a problem with any of them but proofed them with good stiff proof tests more than once. I quit using the stuff when a good friend of mine blew up a heavy blunderbuss barrel made of the same stuff with a standard load for no apparent reason. The guy was a excellent machinist an a real good gun builder with 20 or more years of experience. He has since died from Cancer. He made three other identical blunderbusses that are still in circulation out of the same piece of tubing. Go figure. Spooked me. I made one 11ga. fowler and two or three pistol barrels out of it. I still have one of the pistols

 

[iammarkjones]

This is a test strictly for my own edification. I really don't intend to build a full weapon from it. In my web browsing I have heard NO NO DOM tubing, and the other side saying no problem. I plan to use model a rocket ignition system from a fair distance and see what it takes to cause a truly catastrophic failure... and yeah I got a video camera. BTW I will be on the safe side of a 3/8" thick astraloy shield plate.

 

[Zonie]

IMO, the results of your test will just say what 4140 DOM tubing will do so if it is successful and you publish the results be sure to make sure the reader knows that you are using 4140 steel, not 1018.

Yes, it normally comes in the annealed condition which is considerably weaker than the heat treated condition.

In the annealed condition 4140 is still MUCH stronger than 1018.
My reference says annealed 4140 steel has a tensile strength of around 117,000 psi with a yield strength of 100,000 psi.
Fully heat treated 4140 steel is capable of reaching 290,000 psi tensile with a 251,000 psi yield strength.

Compare this with 1018's tensile strength of 58,000 psi tensile and 32,000 psi yield. (hot rolled)

In other words, comparing your results with something that could be expected from a piece of 1018 steel DOM is like comparing apples with oranges.

Be sure the readers know this.

 

[MRW]

I have a 15 ga. folwer made with 4130 seamless aircraft tube before we used it for a barrel we made a test piece up about 12" long with a breech plug. We miked the tube on 3 diam in 3 places and then proceeded to fire it in a "test" machine with a nipple and cap. we used 250 gr of RS pyrodex with a cast lead slug of bore diam about 1" long tapped down the barrel. We fired this 3 times and could find no evidence of swelling of the barrel with the mikes nor any visible damage, after that we figured a 80 gr load with 1 1/4 ounce of shot would be safe certainly as safe as a original barrel that was probably made from nails and wagon rims that was forge welded. So far the fowler has shot three turkeys and they can't seem to tell the difference between a seamless tube barrel and a Green Mountain barrel

 

[ahil925]

Thanks all for the replies. Those of you testing the DOM and those of you who have built with it, Where did you all get it? Local dealer, recycled construction material, etc?

This current "smoothbore" craze.........

This is the year 2011, you can get a real, honest to God barrel at the drop of a hat, either by purchasing, or making your own if you have the tools.

Barrels with correct historical profiles, made by folks that do it every day are shockingly inexpensive.

If DOM "works"...........then who cares? It's like the guys that are proud as can be that they weld with a coathanger.....real welding rod is pennies a pound and makes 100% better welds. This is just an example.

This is just my opinion of course :grin:

I'm a relatively broke college student. $150+ for the most basic barrels with correct historical profiles is certainly alot more then a drop of a hat to ME. As is the cost of manufacturing equipment to make them myself. Considering that right now I care less about historically authenticity then about learning the how-to's of more basic construction, the price of most company made barrels just doesn't look worth it.

I think my issue right now is that I'm not really after historically accurate work of art. I'm after a muzzle-loader that's not an in-line/synthetic-furniture/stainless-steel/etc. I suppose I could just go but a kit-gun, but the ones I've seen so far just don't do anything for me. Making my own oddball designs seems the most sensible to me.

Just my opinion of course :grin:

 

[necchi]

I'm a relatively broke college student. $150+ for the most basic barrels with correct historical profiles is certainly alot more then a drop of a hat to ME.

Been There, Done That.

Best advice I could offer ya at this point is just wait. Or git the kit as a starter, care for it well and it will retain "resale" value so you can make the step towards what you want later.
You'll still have too throw money at DOM and items to fab it into a rifle/shotgun,, trying to sell that later down the road might be tuff,,

I'm on the side that DOM tubing isn't a real good bet, if it was then all of us would safley be doing it already and DOM guns would be all over the market.

 

[Paul R]

I hear your frustration. A couple possible suggestions come to mind.
1. If you can pick up a used TC Hawken (or one of the other factory guns), you will have a complete set of parts to do a new build. Just need a hunk of wood for a stock.
2. Haunt the want-ads section of this forum for reasonably priced parts. Even place your own 'wanted' ads once you have a start.
3. If there is a ML club,or even just a few shooters in your area, hang out with them. Be friendly and interested. If you use the appropriate amount of humility, somebody might even take you under their wing.
4. Keep lurking around here. There is a wealth of good information available &, as you already know, keep asking questions.

It'll come. Paul

 

[Erzulis boat]

I'm a relatively broke college student. $150+ for the most basic barrels with correct historical profiles is certainly alot more then a drop of a hat to ME. As is the cost of manufacturing equipment to make them myself.

Then you cannot afford it. Building guns isn't for everyone.

 

[ahil925]

Then you cannot afford it. Building guns isn't for everyone.

Once again, your opinion. :grin:

 

[Zonie]

Thanks all for the replies. Those of you testing the DOM and those of you who have built with it, Where did you all get it? Local dealer, recycled construction material, etc?

I suppose you don't want to hear from me because I have not used DOM tubing to make a barrel, but I will mention a few things that one should know before they go out and buy some of it.

Before I start I think it fair to mention that I have many years of experience in engineering design of jet and gas turbine engines plus over 15 years of building muzzleloading firearms.

DOM tubing is not seamless. It has a weld seam running the length of it that is covered by the drawing process.
The weld joint is made by automated equipment and no inspection other than visual is made to assure the quality of the weld joint before the tubing is run thru the dies and over the mandrel.
As it is all automated, visual inspections are rarely done.

DOM tubing can take fairly high pressures but it is not designed to take "explosive" pressures which impart much higher stresses in the tube.
When calculating pressure container stresses, explosive pressure rises should have a safety factor of 4 figured into the wall thickness value.

DOM tubing is made from many different kinds of steel but the most common material is SAE 1018 or 1020, a low carbon, fairly weak material.
I do not recommend using DOM tubing made from 1018 or 1020 material.

If DOM tubing is purchased from a scrap yard or recycled construction dealers there is no way of knowing what the tubing material is.
The only way to know what you have is to buy the tubing directly from a professional tubing dealer and get a written statement of the material properties.

Although I don't know for certain I hope the few muzzleloading gunmakers who use DOM tubing do not use SAE 1018 or 1020 and they get a written statement of exactly what the tubing material is.

The fact that some people have successfully used DOM tubing for muzzleloading gun barrels does not mean that there is no risk. It only means that their barrel has not burst yet.

If we were discussing making a chair or even a cart frame where failure would not be a life threatening possibility I would not be concerned about someone using DOM tubing.
Because death or permanent catastrophic injury is a very real possibility I suggest that anyone considering using DOM tubing for a gun barrel, give it some serious thought.

If the decision to use it is made be sure to know exactly what you have bought.

 

[bioprof]

What is your opinion of the DOM octagon-to-round barrels that used to be sold by Tennessee Valley Manufacturing and those that Jackie Brown used to use on the muzzleloaders that he built? Have you heard of any of those bursting?

 

[Zonie]

I have no desires to own a gun with a barrel made from DOM tubing. There are many other barrels available made from wrought steel which I would choose.

As I recall, Tennessee Valley Manufacturing recently said they don't use barrels made from DOM tubing. I may be wrong in saying that but that's what I recall.

As for Jackie Brown, he claims to know how to use the stuff and I hope part of that knowledge is to know what high strength materials to buy.
I'm pretty sure that he varifies that he got what he ordered.
Here again, I don't know.

No, I can't say I've heard of one of these guns made by either of these companies bursting when they are used and loaded as intended.

I also have not heard of very many guns made in India blowing up but I have no desire to own one of them either.

 

[bioprof]

I think you are correct in that TVM no longer sells them. The last time I looked on their web site, they no longer had them listed.