doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Blow Up EUREKA

Drew, thanks for the update. Great work.

I don't understand a lot of what's going on here, but this is fascinating stuff. Would you consider doing an article for a publication like Double Gun Journal when the testing is finished? This seems like something worthy of permanent preservation.

This is the part of the blow-out piece that was bent almost 90 degrees. Unfortunately, I didn't take a good pic of the crack; on the right at the apex of the bend



This is a 20X photomicrograph after etching with 3% nitric acid/alcohol of the crack area



As part of the failure analysis, Adam is going to label the best images. You can clearly see the crolle pattern; iron is silver-white, steel grey-black. The black dots are graphite (carbon) that are from the cast iron. This crack does appear to be between the iron and steel thin strips that define the 'leaves' within the scroll (the twisted rod). Adam explained the lines at the lower right, but I forgot

This is the first published photomicrograph of a pattern welded barrel!!

And yes, there better be some articles from all this to off-set the almost $1300 for the failure analysis, $125 for MPI, $125 per radiography, and $50-$70 per tensile strength test. AND more photomicrographs if, as I suspect, radiography of a Syracuse Arms barrel at TEAM right now shows a crack.

It would take a significantly larger sample size to convince the gun industry as a whole, but for me this is truly groundbreaking stuff. Wonderful work, Drew. I feel lucky to be able to follow this as it unfolds.
-Will

Drew, I seriously doubt that you will find any of that mythologic interlaminar rust or orange lace in any of your samples. There would have been no red iron oxide on the surface of the iron and steel after they were heated in the forge to welding temperatures, and there would be no surface for exposure to oxidation once the layers were welded. Any thin scale formation that was not scraped, fluxed, or knocked off by hammering would actually be more resistant to oxidation than bare metal. I have seen flakes of mill scale up to 1/8" thick exposed to water for weeks before it gets even a tinge of orange color.

Fantastic stuff here! Thanks again for sharing it with us.

Indeed Keith. Unfortunately, once myth begins, it is repeated by the 'experts' over and over

Gerald Hunter �Don�t Blow Your Head Off!� Gun Digest 1962
Composite barrel metals are brittle, to begin with. The laminations were put together without accurate control, so the walls are not uniformly strong. Each joint of forge-welded metals is a potential pocket of rust or corrosion which holds together today but which by tomorrow may be ready to bust wide open.
Damascus barrels, once thought safe with black powder, are no longer safe! They�re getting older every hour and those hidden rusty � and rusting � areas are growing larger, the barrel walls thinner, and that hundred-and-first shot may blow �em up.

Another gun shop 'expert'. Found this on the internet, but the original source was not sited, nor the date. Anybody know this confused fella?

http://www.freerepublic.com/focus/bloggers/3018315/replies?c=18
Damascus barrels were actually superior barrels when new than many cold rolled welded barrels and hammered steel barrels. BUT, and it is a big but, over time the discontinuities in the Damascus barrel forging technique allows for internal corrosion to form in the hammered wire forging that that forms the Damascus barrels. This corrosion between the mechanical/welded/pressure joining of the metals that are at the core of all damascene metals is unavoidable, weakening the mechanical welded heat bonding because oxygen is incorporated in the joint by its very nature. . . starting the formation of rust at the creation of the barrel. With age, all damascene barrels LOSE considerable strength.
Barrels in that period were ALL proof tested with black powders that were far less pressure producing and slower burning than modern faster burning, higher pressure producing smokeless shotgun powders. Now add the corrosive nature of black powder and the even greater corrosiveness of the fulminate of mercury primers used during the useful life of most of these damascene barrels and its effects on accelerating the corrosion between the domains of the metal in those much more porous barrels. Shooting shotguns with Damascus barrels with modern loads is NEVER advised.
I am past manager of the Olde Sacramento Armoury and I was the appraiser and buyer of used and antique firearms for Simms Hardware (Sacramento) Gun Department � which was named #1 Gun Dealer in the United States in 1971. . . and was a qualified expert in the California Courts on the identification and values of Antique firearms back in the 70s. We labeled every damascene barreled shotgun a wall hanger, a non-shooting relic and instructed all sales people to instruct buyers that they were never to try shooting them as they were considered unsafe. We had several "educational pieces" on hand with blown chambers to show them what would happen if they tried. A couple of those looked brand new. . . and were made by some of those "top names" in gun making from London and New York. They still blew.

Boy the guys in the proof houses were not careful with their proof stamps. According to this expert they must have grabbed the nitro proof stamps by accident a lot of the time.

I couldn't resist...carry on.

No, don't laugh at him, not fair. He was world famous in Sacramento.

BTW, AFAIK Nitro Proof charges in UK were loaded with black powder for many years, and might still be so. Anyone know for certain?

Eug

Drew: Several times you have mentioned "cast iron". I don't believe cast iron was ever used in Damascus barrels. I think that you mean wrought iron, which is very low in carbon content and very ductile versus cast iron which is very high in carbon content and very brittle.