Truth about DOM tubing barrels

[BillinOregon]

I think it is quite one thing to stress test a barrel beyond proof levels, and quite another to proof one. I would not particularly want to shoot a barrel that someone had failed to blow up with a ridiculous load.
But a properly proofed barrel? If proofing has stressed such a barrel to the point that it has become untrustworthy, then no firearm that has been subjected to proofing (as in Britain and Italy) can be trusted. That doesn't make any sense at all.

 

[Va.Manuf.06]

I think it is quite one thing to stress test a barrel beyond proof levels, and quite another to proof one. I would not particularly want to shoot a barrel that someone had failed to blow up with a ridiculous load.
But a properly proofed barrel? If proofing has stressed such a barrel to the point that it has become untrustworthy, then no firearm that has been subjected to proofing (as in Britain and Italy) can be trusted. That doesn't make any sense at all.

As I mentioned above, the government proof load only uses a 30% - 50% overload, not a 100% or greater load that has been mentioned.

 

[Va.Manuf.06]

I think it is quite one thing to stress test a barrel beyond proof levels, and quite another to proof one. I would not particularly want to shoot a barrel that someone had failed to blow up with a ridiculous load.
But a properly proofed barrel? If proofing has stressed such a barrel to the point that it has become untrustworthy, then no firearm that has been subjected to proofing (as in Britain and Italy) can be trusted. That doesn't make any sense at all.

Getz currently uses 12L14 steel. Are you sure Don said that he successfully attempted this test? I know that Dixie Gun Works did it about 50 years ago with some of their barrels and Turner Kirkland clearly stated that the tests showed all of the pressure escaped through the touch hole and none of the short barrel pieces that he used blew up. I always thought it was questionable but he put it in print and no one that I know of proved him wrong.

 

[BillinOregon]

Virginia: I was referring to the 320 grains and two balls load Laffindog menioned. I know the Italian proof house tests at 130 percent of the "service load" and Middlesex VTC will test at 200 percent of service load if you ask them to. I don't know off hand what the Birmingham Proof House tests these guns at, but a UK shooter on another Web site said his Indian-made guns have been proofed by the government. I will try to find out what load they used.

 

[jerrywh]

The thing about modern muzzle loading barrel makers is , they know what kind of steel they are using and they know the physical properties of it. All the ones I know of bore them from a solid bar. All the ones I have made except one were made from a solid bar. That tells me something. As far as I know none of them proof their barrels because they know what the yare made of and how they are made. Personally I don't trust anything with my life and my freinds lives. I proof every gun I build. I use standard proof loads from the old proof charts. Dixie catalog has some good proof information. I have tested barrel for at least 50 years and never had one blow up but I had one that would have if I had not spotted the defect under a microscope before it was proofed. A good friend of mine had one blow up with a standard load that was made from Shelby seamless steel tubbing. That convinced me not to use tubbing. I once did the same test that John Getz did on a piece of barrel back about 1954 or 55. The same thing happened. All the pressure went out the vent hole and it never blew up. What rally bothers me about the indian barrels is I don't know what they are made of or if they are tested. I just don't like tubbing. I don't know any professional barrel maker who trusts it. I would never buy a gun that had a barrel made from it.
This is one of those debates that will never be settled. A person can only determine what he or she will do. But they are not for me.
PS. Pedersoli told me the Italian proof house tests back powder arms for 41000 psi. The maximum service charge is 29000 psi.

 

[Va.Manuf.06]

IIRC, Birmingham uses no more than a 150% load for proof, at any rate it is similar in power to that used by the Italians or any other proof house in Europe.

I don't have time to look right now but you may find out some information here:
http://www.gunproof.com/index.html

 

[Va.Manuf.06]

Jerry, wise words. However I don't think Don Getz did any proofing in 1954, Getz started business after he bought out Paris in the late 1970s IIRC. You may be thinking about Turner Kirkland?

 

[matt denison]

Don Getz did blow a barrel, in fact two of them. His objective wasn't to show how tough they are but the characteristics between soft steel (12L14) and high speed (1137?). The 12L barrel ruptured, the high speed barrel shattered. That is why he said he would use 12L. Even if it lets go it is safer than shrapnell from the modern alloyed stuff. I hope this helps clear up the "who did what when" confusion.

Also you will have to do an awful lot of talking to convince me that plugging a barrel at both ends and touching off a healthy charge of gun powder will not result in catastrofic failure. Ever hear of a pipe bomb?

One more thing: Barrels aren't necessarily subject to failure under normal use. It's when something or a combination of things come together such as shooter error, short starting with large amts. of powder or double charging or introducing a barrel obstruction that causes barrels to fail and guys like me to loose sleep at night. That is why when asked what the max. load is for one of my guns I answer "whatever you feel comfortable with if you accidentally double your charge, go with half of that." Not kidding.

 

[Va.Manuf.06]

Don Getz did blow a barrel, in fact two of them. His objective wasn't to show how tough they are but the characteristics between soft steel (12L14) and high speed (1137?). The 12L barrel ruptured, the high speed barrel shattered. That is why he said he would use 12L. Even if it lets go it is safer than shrapnell from the modern alloyed stuff. I hope this helps clear up the "who did what when" confusion.


:thumbsup: It does.

Also you will have to do an awful lot of talking to convince me that plugging a barrel at both ends and touching off a healthy charge of gun powder will not result in catastrofic failure. Ever hear of a pipe bomb?

I agree completely, I can't see how it wouldn't blow up.

One more thing: Barrels aren't necessarily subject to failure under normal use. It's when something or a combination of things come together such as shooter error, short starting with large amts. of powder or double charging or introducing a barrel obstruction that causes barrels to fail and guys like me to loose sleep at night. That is why when asked what the max. load is for one of my guns I answer "whatever you feel comfortable with if you accidentally double your charge, go with half of that." Not kidding.

You are correct.

 

[jerrywh]

Yep I know all about pipe bombs, but his one never blew up.
I did that test way before I ever heard of John Getz. John told me about his about 15 years ago It seems.
"One more thing: Barrels aren't necessarily subject to failure under normal use. It's when something or a combination of things come together such as shooter error, short starting with large amts. of powder or double charging or introducing a barrel obstruction that causes barrels to fail and guys like me to loose sleep at night. That is why when asked what the max. load is for one of my guns I answer "whatever you feel comfortable with if you accidentally double your charge, go with half of that." Not kidding."
I agree, not normally but once in a while.

John or Don never told me about blowing up any barrel but I don't doubt that. Long Hammock uses 1137. 1137 and 12L14 are both manganese steels I believe.

 

[matt denison]

Long Hammock does use 1137 and 12L14. I get my smoothbore barrels drilled and reamed by Riley @ L.H. out of "12L" not because of the strength but because of the shooting characteristics of it. I do believe 12L to be very forgiving on what you can load and shoot accurately in it. Stiffer barrels (1137) are much more finnicky what load they want where 12L will shoot with a wider range of powder/ball/patch combo's. This is my opinion backed up by... uh, oh, better save it for another thread. :shake: :surrender: :grin:

 

[LRB]

Other than assisting in heat treat, I don't recall manganese offering any extra strength. 12L14 is leaded for easier machining. 1137 is not. Just my thoughts, but the tubing doesn't worry me that much, when used with reasonable loads. And I have read that the India government is stricter than most when it comes to proof testing. The catch is, if the barrel has no vent, then proofing is not required, but if it is produced in India, with a vent, it has to be proofed, and it is well proofed.

 

[Rolfkt]

I have no intention to make a barrel out of DOM tubing, but I'm curious to why such a barrel should be more dangerous than a traditonal forged barrel?

Best regards
Rolf

 

[schloss]

Has anyone taken the time to xray some DOM tubing, or run a magnetic particle inspection on them? Just curious. I was thinking about trying it sometime in the next few months if I can get the chance, but I may not be allowed to.

If done properly, the xray will show any voids, cold shuts, lack of fusion, etc., as well as inconsistencies in the material. Obviously won't give us the stress limits of the material, but would show the quality of the critical weld area. Obviously, the xray inspection would need to be performed properly and multiple shots will be required for each section of tubing inspected, just thought it would be worth checking into if anyone else has access and time.

 

[rich pierce]

I have no intention to make a barrel out of DOM tubing, but I'm curious to why such a barrel should be more dangerous than a traditonal forged barrel?

Best regards
Rolf

I think that was covered above in discussions about the type of weld. A scarfed weld has a much greater surface area. Also wrought iron MAY be more prone to bend or elongate than shatter in bad circumstances, like a plugged muzzle or a ball not seated all the way. I think the real fear is that they may not hold up as well as some bored barrels or forge welded barrels when serious mistakes are made. I know 2 highly experienced shooters who ruined high quality barrels by short starting the ball, getting distracted talking to someone or offering advice to a newbie, failing to ram the ball home, then firing the gun. In one case a famous maker barrel split right at the front sight dovetail and the sight embedded in a rafter overhead. The failure did not elongate or shatter or throw shrapnel. Perfect outcome. The other failure was similar, caused by operator error, similar outcome, nobody hurt.

 

[Rolfkt]

Rich said:
I think that was covered above in discussions about the type of weld. A scarfed weld has a much greater surface area.

This is what I find confusing. The DOM tube is scarfed welded. Because of the greater suface area,I would have thought it was stronger than a traditional butt welded rifle tube.

Best regards
Rolf

 

[rich pierce]

No kidding? I thought I read it was butt welded

 

[George]

No kidding? I thought I read it was butt welded

It can apparently be done either way. I said earlier that it was a butt joint, but further reading makes it clear that's not necessarily the case. I think something is being missed in this discussion. The welding process used to make the tubing isn't like conventional welding. It's a manufacturing process using induced current to bring the metal edges to a plastic state and then forcing them together under tremendous pressure to fuse them into one piece. It is frequently referred to as a forged joint and said to be stronger than the original material because of that.

All of this is way above my pay grade, but a lot of information is available about ERW welding and DOM tubing, and it seems very different from what most in this thread seem to assume. It is well established and proven technology.

When I learn that the metallurgical report on the steel the tubing my gun is made from shows "ultimate strength-104.800 psi, yield strength-94,100 psi, elongation in 2 inches-17.0%, hardness (RB)-96", it is greek to me. I have no idea how that compares to the steel in a drilled barrel, and I doubt I could ever find out.

As is usual in these discussions there is a wealth of opinion and a dearth of evidence, so nothing can really be learned.

Spence

 

[Zonie]

When I think of ERW (Electrical Resistance Welding) my first thought is about what is called a "spot weld". Yes, the process for a continuous ERW weld on tubing is slightly different but not much. For what it's worth, a TIG or MIG weld is usually a better, more complete weld but it costs more than the ERW process does.

I guess my background doesn't carry much weight anymore but after 39 years of mechanical and Engineering Design where I had to know about the many processes and material properties I would hope it counts for something.
Had this time been spent designing door locks or wheel barrows perhaps my knowledge would be rather limited but the gas turbine engines and jet engines I was a part of designing are considerably more complex and require a much higher degree of knowledge about materials, processes and inspection requirements.

When I give my opinions about such matters and folks casually disregard the information after reading about matters that they admit they don't fully understand all I can do is shrug my shoulders.

The bottom line is I do not recommend using DOM tubing for a barrel. There are many good options for barrels available from reputable barrel makers who do know what they are doing and it makes no sense to use materials that are potentially of a lower quality.

 

[Dave K]

Just what is wrong with a barrel that is designed and made to be a gun barrel?