Pressure loads

[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

[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.

[Michael rivers]

Thanks that’s great info

[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!

[Dean Romig]

Originally Posted by Michael rivers

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.

[Michael rivers]

Ok great thanks I just need numbers to refer to.