Pressure loads

[Michael rivers]

Hi guys I want to know if there is any evidence on breaking loads on barrels instead of just saying you can’t use modern loads or you will lose your face.
Is there actual evidence of pressure testing on a Parker barrels when they were made stating that there needs to be let’s say a 5 to 1 working pressure ratio?
As with Remington it is 55000 psi breaking load

[Dean Romig]

Yes there certainly is evidence. You don’t get to be one of the most highly respected gunmakers in the the country, or even the world, if you didn’t have standards.
Every Parker made came with patterning tags with powder and shot load data including specific measurements. Anyone who chose to use greater loads than those specified on the tags did so at their own peril... to life and limb... or digits.






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[Michael rivers]

Ok great! Do you know where I can get the breaking loads ?
Thanks mike

[Michael rivers]

Need the breaking loads for a titanic barrel?

[Dean Romig]

There is no “one size fits all” formula. Each bore size and frame size had its own recommended load. In fact you could almost say that each gun was different, even though they weren’t, but “The Parker Story” certainly explains it a lot better than I can.






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[Michael rivers]

Ok so there isn’t a breaking load chart for a 12g.
I thought this information would be easily accessible due to safety

[Daniel Carter]

Please explain what you mean by breaking load. Do you mean proof load, or one that will definitely blow the gun up. I am confused in that i have never heard the term.

[Michael rivers]

Sorry I mean what pressure rating did the Parker barrels fail? Then you can determine what low pressure is.

[Cameron Thraen]

Read 'Finding out for myself' series of articles by Sherman Bell published in The Double Gun Journal. Excellent work reported on proof loads and gun failure. You will be surprised at the pressure required to cause failure.

[Michael rivers]

Great thanks ile take a read ����
The reason I ask is because for there to be low pressure ammo there has to be a failing number to state that.

[Michael rivers]

I read an article that states they tested a Remington 870 and it failed at 65000 psi

[Bruce Day]

This has been covered many times here . Parker recommended service load pressures, proof load pressures and recommended charges are published in The Parker Story .

Pressures for test to destruction were published by Sherman Bell in the Double Gun Journal .

Modern loads is meaningless. Many commercially available cartridges today are suitable . Some such as Prairie Storm exceed recommended pressures.

Here are Parker recommended loads expressed in drams of powder and ounces of shot. Powder loads can be converted to drams equivalent.

[Dean Romig]

Just because a good gun can easily withstand a proof load withous suffering any visible or even measurable effect does not mean the gun should be subjected to such stout loads except during a proof test. A particular proof load is about twice, or greater, the recommended max for a gun. I like to stay well below 7,000 psi in any of my guns, even fluid steel barrels. Keeping in mind that the barrels are not the only parts of a gun that undergoes stress every time the gun is fired.





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[Michael rivers]

Think I just found the info and the titanic steel barrels are rated to 75000psi when new!

[Michael rivers]

I get your point the reason I wanted to know because the way people talk about old guns it is very unnerving and almost put me off buying a good old piece of history.

[Michael rivers]

Thanks that’s great info

[todd allen]

Parker's are not just any "old guns". If you want to see something amazing, see if you can track down the Double Gun Journal article by Sherman Bell called "Finding Out For Myself".
Mr. Bell does pressure tests on old Parker Damascus barreled guns. He uses old rattlely worn out guns, just to make it interesting. Runs blue pill proof loads through them, gradually increasing the pressures of the loads, to see how far they would go before they burst.
They went out to 30,000 lbs plus, before showing any signs of stress.
For the record, none burst.

[Dean Romig]

Think I just found the info and the titanic steel barrels are rated to 75000psi when new!

This has absolutely nothing to do with pressures Titanic Steel, or any other barrel steel, should be subjected to. Sherman Bell destroyed a set of Parker barrels at something like 31,000 psi.
I’m sure you will find that the 75,000 lbs you refer to is “shear strength” and not distortion or burst pressure.

A proof load for Parker fluid steel barels is well under 20,000 psi and should never be subjected to loads of even half of that.

Again, I keep all of my loads, even for my Titanic barrels, at less than 7,000 psi and they do everything I ask them to do.






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[edgarspencer]

Perhaps shot-shell manufacturers should refer to their 'low' pressure ammo as ' lower' pressure, but they (and I) probably don't need to know what pressure is necessary to blow up a barrel. It's easy enough to know the range of pressures being offed, and if their's falls on the lower end of the scale, that's all that necessary to legitimately call them low pressure.
Lots of tests have been run on various steels used to make barrels by Parker Brothers. These tests, undertaken by members, and using labs and procedures considered meeting standards such as ANSI, ASTM, ASME, and NAVSEA, were published both here, and in Parker Pages articles.
Alloy steels, typically CrMo, and CrNiMo, have UTS (Ultimate Tensile Strength) above 80,000 psi, and most are in the 90-60 range (90,000 UTS, and 60,000 Yield strength) not,"Shear Strength" as stated above.

I don't think anyone has ever done extensive testing on composite barrels like that done on steel barrels. In order to do a proper test, samples would be examined both non destructively and destructively. It's pretty hard to say what is "specification" as you're dealing with at least two distinct materials, and in a form which would be difficult to segregate. These materials aren't homogeneous but from a practical standpoint, have to be treated like they are, knowing any test results are pretty random.

[Stan Hillis]

Michael, the best information, IMO, to figure out what I think you are trying to determine, is the pressure data for commonly sold shells that were in service during the time the guns were made and used. Much data exists on what those pressures were. Many readily available loadings of the day were in the same range as our modern shells (up in the 10,000 psi range).

A comparison using pressures necessary to cause a gun to fail when new would be useless unless you knew what it would take to cause that same gun, after 100 years of use, to fail. Bell comes the closest, in modern times, to doing that of anybody we know of. But, it's only 100% valid for that particular gun, because of the way condition varies so much with vintage guns. It may, however, be somewhat meaningful for us.

Some have graciously posted charts and figures that show the pressures of vintage loadings, and you could probably find them with some searching, or they may read this and repost them.

When we call a loading a "lower pressure" load it is usually the result of a personal comparison of the pressure of the load(s) in question with the pressures of the loads of the day. I base that call on the individual gun in question ....... it's condition, and what it was designed to shoot originally. I've loaded and used shells that range anywhere from 5500 - 10,500 psi in my vintage guns, though not all of them were "lower pressure" loads. Remember, higher pressure does not hurt wood on a gun. It only places increased stresses on the action, the lockup and the the barrels. Recoil resulting from a heavy payload, and higher velocities, is what is a detriment to old wood in poor condition.

So, what it comes down to is whatever an individual considers "low pressure". If the gun was designed to shoot 10,000 psi commercially loaded shells I personally consider anything from 8500 psi down as being "low pressure". Others would not consider 8500 psi "low", but it certainly is lower.

[Dean Romig]

I stand corrected - thank you Edgar. I had a gut feeling you would come on and do that. So thank you for ‘simplifying’ it all for us.
Your background in metals production, forging, etc. and your training and experience in metalurgy qualifies you to do so... so again Thank You. I used the wrong term. You used the right term and backed it up with data.

I guess my response to Mr. Rivers was meant to direct him away from any assumptions he may have been making about 75,000 lbs having anything to do with reasonable (sane) loads we should be using in these old guns.





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[Drew Hause]

Here you go
Barrel Steel Strength & Composition
https://docs.google.com/document/d/1dnRLZgcuHfx7uFOHvHCUGnGFiLiset-DTTEK8OtPYVA/edit
A pre-WWI Titanic steel barrel was AISI 1030 with an industrial standard tensile strength (which is NOT bursting pressure) of about 75,000; which was similar to most pre-WWI Belgian sources fluid steel tubes used by U.S. makers

Turn-of-the-Century Shotshells, Powder, Proof & Ballistics
https://docs.google.com/document/d/1F2sQuPm05IE4VWYYnCkvuXmYEzQoWd_SQgaAfUOZEFU/preview

Scroll down about 1/4 for an explanation of Parker Bros. proof testing

The 1893 Parker Bros Catalogue documented proof testing with Smokeless Powder in house
"Our guns are bored on the latest improved system for shooting Nitros, or Smokeless Powder, and all our guns are tested with some one of the most approved makes, and a tag accompanies each gun, giving the results of such a (pattern) test."

A Parker Service and Proof Load table was published in the 1930s and reproduced in the The Parker Story p. 515.
12g 2 3/4” shell Service Pressure is 10,500 psi. Definitive proof used 7.53 Drams Black Powder and 2 oz. shot with a pressure of 15,900 psi. The pressure was no doubt measured using LUP and modern transducer values would be 10-14% higher, or more than 17,500 psi.

LTC Calvin Goddard reported the same numbers in “Army Ordnance”, 1934. He wrote that Parker followed the SAAMI standards of that period: 13,700 psi proof, 9500 psi service for 2 5/8” chamber; 15,900 psi proof, 10,500 psi service for 2 3/4” chamber (by LUP) + 10-14% for modern transducer measurement.

[Michael rivers]

Ok great thanks I just need numbers to refer to.

[Michael rivers]

Here you go
Barrel Steel Strength & Composition
https://docs.google.com/document/d/1dnRLZgcuHfx7uFOHvHCUGnGFiLiset-DTTEK8OtPYVA/edit
A pre-WWI Titanic steel barrel was AISI 1030 with an industrial standard tensile strength (which is NOT bursting pressure) of about 75,000; which was similar to most pre-WWI Belgian sources fluid steel tubes used by U.S. makers

Turn-of-the-Century Shotshells, Powder, Proof & Ballistics
https://docs.google.com/document/d/1F2sQuPm05IE4VWYYnCkvuXmYEzQoWd_SQgaAfUOZEFU/preview

Scroll down about 1/4 for an explanation of Parker Bros. proof testing



The 1893 Parker Bros Catalogue documented proof testing with Smokeless Powder in house
"Our guns are bored on the latest improved system for shooting Nitros, or Smokeless Powder, and all our guns are tested with some one of the most approved makes, and a tag accompanies each gun, giving the results of such a (pattern) test."

A Parker Service and Proof Load table was published in the 1930s and reproduced in the The Parker Story p. 515.
12g 2 3/4” shell Service Pressure is 10,500 psi. Definitive proof used 7.53 Drams Black Powder and 2 oz. shot with a pressure of 15,900 psi. The pressure was no doubt measured using LUP and modern transducer values would be 10-14% higher, or more than 17,500 psi.

LTC Calvin Goddard reported the same numbers in “Army Ordnance”, 1934. He wrote that Parker followed the SAAMI standards of that period: 13,700 psi proof, 9500 psi service for 2 5/8” chamber; 15,900 psi proof, 10,500 psi service for 2 3/4” chamber (by LUP) + 10-14% for modern transducer measurement.

Great! Thanks so much for that info. I just need to know facts instead of assumptions.

[Drew Hause]

Michael: this is important
Tensile strength is only a part of the equation for estimating bursting pressure. If the barrel is made of Twist with a 50,000 psi tensile strength, that does NOT mean that it will withstand a 10,000 psi load by a factor of 5.

Barlow's formula P=2 S t / D
P=Bursting pressure in psi.
S=Tensile strength of material in tube wall.
t=Wall thickness in inches.
D=Outside diameter in inches.

Barlow’s refers to a pipe capped at both ends with a static pressure (a pressure cylinder) so does not work well for unobstructed shotgun barrels; which are not designed to be pressure vessels as one end is open and the pressure rises and falls quickly.

The Hoop Stress Formula doesn't reliably predict shotgun barrel failure either
Shotgun barrels are "thin wall cylinders"
σ = pr/t
p= pressure; r is the inside radius; t is the wall thickness

BTW: Wallace H. Coxe, in "Smokeless Shotgun Powders: Their Development, Composition and Ballistic Characteristics" published by E.I. du Pont de Nemours & Co. in 1931 cites a study in which a fluid steel barrel was cut to 9” and capped, then a series of progressively increasing pressure loads fired. The barrel cap was blown off and barrel burst at only 5,600 psi.

[Michael rivers]

There’s no argument here all I need to know is what test did Parker’s bro’s do on there barrels
So no ones right or wrong I’m asking for data that Parker bro’s held.

[Mike Koneski]

Read 'Finding out for myself' series of articles by Sherman Bell published in The Double Gun Journal. Excellent work reported on proof loads and gun failure. You will be surprised at the pressure required to cause failure.

Cameron, if I remember correctly, Sherman Bell used modern proof loads to test those guns, and there were a lot of guns. I remember he had some movement between the hook and hinge pins but no barrels let go. Some of those guns surprised him that they held up as well as they did. Great series of articles.

[Drew Hause]

The Double Gun & Single Shot Journal "Finding Out For Myself" series by Sherman Bell with technical assistance from Tom Armbrust
Vol 10, Issue 2, Summer 1999, Part 1, p. 9
Vol 10, Issue 4, Winter 1999, p. 21 - Destructive testing of Parker GH Damascus
Vol 16, Issue 2, Summer 2005 - Destructive testing of Parker VH Vulcan Steel
Vol 17, Issue 3, Autumn 2006, p. 12 - Destructive testing 8 Damascus doubles
Vol 17, Issue 4, Winter 2006, p. 28 - Destructive testing 7 Damascus
Vol 18, Issue 1, Spring 2007 -
Destructive testing on a Damascus barrel with thinned walls; calculated by O.D. - I.D. and not measured.
Destructive testing using various obstructions, including a 20g shell.
Destructive testing using a shell loaded with 3 1/4 Drams by volume or 56 grains of Unique (similar to “Infallible”) with 1 1/4 oz. shot. The chamber burst with the first shot.
The 3 1/4 Dram Equivalent load is 24 grains of “Infallible”.
Vol 19, Issue 2, Summer 2008, p. 18 - Destructive testing 1 Damascus, 6 Twist
Vol 20, Issue 3, Autumn 2009, p. 108 - Destructive testing 1 Damascus, 5 Twist “Bottom-Of-The-Barrel Wall-Hangers”

The Remington Proof Loads used by Sherman Bell and Tom Armbrust were measured to be 18,560 psi.
Total 28 vintage doubles/54 Twist and Damascus barrels + 2 Vulcan (Fluid) Steel

[Jay Oliver]

That is a great resource right there...Thanks for posting that Drew! What a valuable list.

I have been wanting to get some of those articles and back issues and didn't quite know where to start.

Thanks again!

[Cameron Thraen]

I have read each article. The work they completed, with precision and attention to detail, was excellent. If only I had this information in my early days when I either passed on or sold a few really nice Parkers and other Damascus barreled guns on the old gunsmiths advice "wall hanger, shoot it and you'll lose your fingers". I remember, long ago, a particularly stunning Parker D that I could have purchased except for a gunsmith's opinion that he could detect a 'stretching' in the Damascus at the breech end so I passed. Sigh.