Barrel wall thickness

[AmarilloMike]

I copied this from a post I made over on the Doublegun BBS:

I sure have a lot of doubles with original chambers and forcing cones with wall thicknesses way below .100" at the end of the chamber.

Fox A grade 16ga, 26" barrels, 2-7/16" chamber, 0.085" and 0.086" minimum wall thickness at the end of the chambers, .734" and .734" diameter at the end of the chambers, 5/8" long forcing cones, #4 barrels, gun weighs 5lbs 9oz, serial 302XXX.

Parker VH O Frame 16ga, 28" steel barrels, serial 134XXX, 2-9/16" chamber, .082" and 0.085" minimum wall thickness at the end of the chambers, 0.730" and 0.732" end chamber diameters, 3lbs 2oz unstruck barrel weight, gun weighs 5lbs 14oz.

AYA #1 20 bore sidelock, factory 2-3/4" (70mm) chambers, 30" barrels, built and proofed in 2006, .092" and .091" minimum wall thickness at the end of the chambers. Skeets gauges unable to measure chamber diameter. Gun weighs 5lbs 13oz.


Fox XE 16ga, 30" barrels, serial 301xxx, .072" and .080" minimum wall at chamber ends, 2-7/16" chambers, .733" and .733" end chamber diameters, gun weighs 6lbs 3oz

Parker DHE 16ga, 32" steel barrels, serial 212XXX, 0.090" and 0.092" minimum wall thickness at chamber ends, 2-9/16" chambers, .735" and .736" diameter at chamber ends, barrel unstruck barrel weight 3lbs 11oz, gun weighs 7lbs 4oz.

Lefever H grade 16 gauge, 28" twist barrels, .090" and .092" minimum wall thickness at chamber ends, 2-5/8" chambers, .729" and .728" diameter at chamber ends. Gun weighs 6lbs 4oz

Ithaca Flues Grade 4E 16 gauge, 28" Krupp fluid steel barrels, 0.091" and 0.092" minimum wall thickness at the end of 2-5/8" chambers, daimeters of .728" and .730" at the end of the chambers, gun weighs 6lbs 6ounces.

Parker DH 12 bore, 28" Damascus barrels, 1 frame, .086" and .090" minimum wall thickness at end of the 2-5/8" chambers, gun weighs 6lbs 14oz. Serial #84XXX, My Skeets gauges are incapable of measuring the diameters at the end of the chamber.

Bissel Birmingham boxlock, 20 gauge, 25" steel barrels, made in the 1920s, .084" and .092" minimum wall thickness at the chamber ends, 2-1/2" chambers. My Skeets gauges are incapable of measuring the diameters at the end of the chamber. Weighs 5lbs 7oz.

[Holeshot]

Mike, looks like you have an interesting collection of 16's. Which is your favorite? Dave

[Ruff Hunter]

This has been a great and informative thread. In that regard, what's the consensus on the safety shooting factor of this DH? I do note that the chamber/forcing cone minimum barrel wall thickness measurements are needed.

http://www.gunbroker.com/Auction/Vie...Item=304446791

[Steve McCarty]

Originally Posted by Justin Julian

This has been a great and informative thread. In that regard, what's the consensus on the safety shooting factor of this DH? I do note that the chamber/forcing cone minimum barrel wall thickness measurements are needed.

http://www.gunbroker.com/Auction/Vie...Item=304446791

To my eye those barrels look plenty thick. The safety of shooting those fine damascus barrels has been much discussed here. I suggest you find Sherman Bell's articles in Double Gun magazine. He has done extensive research and many tests shooting those damascus/twist tubes. He had a difficult time getting them to let go, even when shooting modern proof loads.

You can also buy lighter loads made specially for the older guns. Look up RST and Polywad shot shells.

Summery, you can find very safe ways to shoot and enjoy guns like these and if in good condition, they are safe when shot with proper loads.

[AmarilloMike]

Originally Posted by David Holes

Mike, looks like you have an interesting collection of 16's. Which is your favorite? Dave

David I couldn't choose one. The Parker VH 16 and the Fox A grade 16 are neck and neck for my favored Bob White gun. The stock is lower on the Parker and I shoot it a little better.

The Fox XE is a fine gun and maybe the prettiest gun I own. 30" barrels make it nice for dove.

The DHE 16 with the 32" barrels is a great dove gun. A few years ago I took it to Argentina.

I shoot the Flues very well, perhaps better than any other gun I own.

Besides the list above I also have a Parker VHE 16 O frame that weighs 5-3/4 pounds with 26" barrels that I really like. And a Birmy boxlock 16 (Gallyon) the weighs in at 5-9 with 28" barrels that was my first love in double guns.

So I guess the answer is that I don't know.


And thanks!

Mike

[Richard Flanders]

Jay's long response to this question is first class. Factual, logical and to the point. I for one copied it into Word so I can refer to it without having to search for it and show it to friends who might ask the question. Thanks Jay. Very well done.

[Bruce Day]

Back to top. Persons interested might read Jay Shachter's post.

[Drew Hause]

This information was part of a separate thread, but will add it here
http://parkerguns.org/forums/showthread.php?t=10889

Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives (C.I.P) http://www.cip-bobp.org/

Shotgun recommended minimum wall thickness p.4

http://www.cip-bobp.org/sites/defaul...e/A-4-1_EN.pdf

For 10 & 12g Standard Steel................................20g Standard Steel

End of chamber - .079”............................................. ....... .075”

Just past the forcing cone/ 4” from breech - .075”................. .071”

8” - .043”............................................. ........................... .041”

12” - .030”............................................. ......................... .028”

16” - .024”............................................. ......................... .022”

20” - .022”............................................. ......................... .020”

FAQ http://parkerguns.org/pages/faq/BarrelThickness.htm

[Bruce Day]

And that correlates to what service and proof loads?

[Drew Hause]

There are three pressure measurement systems (lead crushers/LUP, copper crushers, and piezo), and two standard systems of measure units (USA/SAAMI and CIP/British/European) and two differing units (psi and tons and BAR in kg/cm sq) within each system, different proof laws by country, and differing proof laws by age.
Unfortunately, there is essential NO formula to convert BAR expressed as LUP (CIP) to PSI (SAAMI). LUP + 1000 does not reliably predict the actual piezoelectric transducer measured pressure.

That said, European (CIP) "standard" proof pressure of 850 kg per sq. cm. (BAR) = about 13,920 psi proof pressure = 10,730 psi service pressure (SAAMI)