Very Interesting Damascus Topic Thread.

[Austin W Hogan]

When someone prepares an article on Parker barrel testing, Parker Pages will certainly carry it. There is an informal report on metallurgical analysis of some barrals but it hasn't really been submitted for publication.
Two accomplished tool designers, Larry Frey and Dave Suponski are currently working with some twist and damascus barrel segments, trying to learn the cutting methods used to shape these barrels. This is an important first step in designing a non destructive test method as well as learning how early Parker barrels were made and finished.
Would you send a set of Dam 6 barrels for proof? Probabably not. There are two non destructive tests that need to be established; first a test that will determine if thin spots or seams less than 1/8 inch in diameter or width are present; second a test for ductility that will determine if the barrel metal has been embrittled by age, corrosion or heat cycling.
The first could probably be achieved by an industrial X ray, using similar techniques to testing steam pipe welds. The second might be done by measuring stretching and return to original dimensions as is done on gas cylinders. The question here is one of sufficient tests purchased to off set the original development costs.
Assuming these tests were designed; would you send a collector gun for analysis if you knew that some apparently high condition guns were found to be thin or brittle?

Best, Austin

[Dean Romig]

Originally Posted by Austin W Hogan

Assuming these tests were designed; would you send a collector gun for analysis if you knew that some apparently high condition guns were found to be thin or brittle? Best, Austin

Ans: No I wouldn't.

Austin, do we know of any barrels, Damascus or otherwise, that have been proven to have failed due to the metal having become "brittle"?

Do we know that this becoming "brittle" is a normal condition of aged gunbarrel metal?

[Austin W Hogan]

Dean; I think it is pretty apparent; when ductile barrels let go, due to overloads or obstructions, the barrel bulges and /or splits. When non ductile barrels let go they shatter and pieces become detached. These pieces are the things that generally cause injury.
There are a couple of stores near me that have blown composite barrel guns hanging over the register or rack. I had access to many club's blown gun exhibits during the 15 years I was a hunter training instructor; as I remember, all had metal missing.
One of our members has a lifter that let go at a thin spot; it was repaired and still is a beautiful gun, although it probably will never be shot again. Barrels that fail due to embrittlement cannot be restored.
And so we arrive at a quandary; a positive thickness and ductility test is certainly a positive factor in assessing a gun; does a negative test produce a beautiful wall hanger?

Best, Austin

In code welding, hydrogen embrittlement in the HAZ of the weldment can cause failure- in fabrication and structual grade steel- so preheat, post heat and use of low-hydrogen filler rods (AWS code 7018 for example) can prevent this form of weld failure-

As Damascus and twist barrels were "welded" so to speak- ie: heat and hammer blows of the twists of iron and steel over a mandrel, would trace hydrogen also play a part in latent embrittlement in these barrels?

Ductility would usually result from Mn and Si added to the steel during the BOF (or later, electric melt) furnace- but the iron strips, a different story perhaps-

I was just out shooting barn pigeons today with two of the 12 gauge Parkers- the GHE with Vulcan Steel barrels, and the PH with parker twist barrels- shot RST 2 & 3/4 dram 1 & 1/8th oz. No. 8 and Win 2 &3/4 dram lite 1 oz no. 9 shells- never have had one problem with that PH made in 1902 using those lower pressure loads, and the birds seem to crumple up in the air at my comfortable pass shooting range- no need for the more expensive HV loads at all- no recoil, easier on the wallet too-