Barrel Analysis

[Drew Hause]

This might help Richard

Greener on Stub Twist in The Gun, or a Treatise on the Various Descriptions of Small Fire-Arms , 1835
http://books.google.com/books?id=oIEY4qL6_z0C
Stub-Twist Iron - Made from a 1:1 ratio of horse-nail stubs (iron) mixed with chopped coach spring steel, fused ("puddled") into a "bloom of iron", then hammer forged or rolled into a rod NOT twisted, which was then wrapped around a mandrel and hammer welded.

Appleton's Dictionary of Machines, Mechanics, Engine-work, and Engineering
D. Appleton and Company 1873
http://books.google.com/books?id=zi5VAAAAMAAJ
Gun Barrels
http://books.google.com/books?id=zi5...AJ&pg=PA936&dq

It need hardly be remarked, that the advantage to be derived from the use of horse-shoe nails does not arise from any virtue in the horse's hoof, as some have imagined, but simply because good iron is, or ought to be, originally employed for the purpose, otherwise the nails will not drive into the hoof; and the iron, being worked much more, is freed from its impurities, which can only be effected by repeated workings.
For the finest description of barrels, a certain proportion of scrap steel, such as broken coach-springs, is cut into pieces and mixed with the iron by the operation called puddling, by which the steel loses a considerable portion of its carbon, and is converted into mild steel, uniting readily with the iron, and greatly increasing the variegation and beauty of the twist.

Several authors commented that horse-shoe stubs became increasingly difficult to obtain by the mid-1800s leading to more Plain Twist/Wire Twist/ Skelp (all the same stuff) and Laminated Steel barrels

More information here
http://docs.google.com/a/damascuskno...LxMESM3W0/edit

[Drew Hause]

The Modern Sportsman's Gun and Rifle: Including Game and Wildfowl Guns, Sporting and Match Rifles, and Revolvers
John Henry Walsh (Editor of The Field) 1882
http://books.google.com/books?id=OLwUAAAAYAAJ
“CONSTRUCTION OF THE GUN”
http://books.google.com/books?id=OLw...cad=0#PPA83,M1
THE BARRELS
Whatever may be the kind of gun about to be made, the first thing done is to forge the tube or tubes containing the charge. Formerly they were all made of plain iron, but for the last hundred years the barrels of all best guns have been constructed either of strips or twisted iron coiled spirally round a mandril, and welded together by heat, or of steel. At present the selection is from three kinds, viz., first, Damascus; second, laminated steel; and third, plain steel.
The chief difficulty in the present day is to obtain iron of sufficiently good quality to mix with the steel, whether for Damascus or laminated barrels. Formerly horseshoe stub nails were alone thought good enough; but of late years these have fallen off in quality, and are also insufficient for the supply of the increased demand for shot guns since the passing of the present game law. These stubs, generally mixed together with other "scraps," were welded together and forged into bars; but in the present day new iron is alone used, selecting the best quality in the market, and refining it by melting and puddling, after which it is submitted to the tilt hammer, by which its fibres are condensed and drawn out.

[Gunner]

Richard, I have questions regarding "Aston Twist Parker barrels." I am not familiar "Aston Twist" How are such Parker barrels marked on the top rib and on the barrel flats if they are marked? Is this twist distinctive in appearance from other twist barrels? Do the surviving Parker records distinctly reference "Aston Twist" and have any letters documented same?
Thank-you for any information you can provide.
Erick

[Drew Hause]

An update
http://www.doublegunshop.com/forums/...=357105&page=8

[Eldon Goddard]

The results seem to me to be the same that Zircon posted and I discussed with him. Drew glad to see some one putting in the hard work.

[Drew Hause]

Eldon: One important difference is that Bell's blown up barrels were subjected to sequentially greater pressures until failure, and DID show low cycle fatigue. The blow out being investigated now was a single over-pressure event, and low cycle fatigue was NOT seen. This is important in that it has been claimed that all Damascus eventually fails from internal rusting and weld failure (NOT seen) and low cycle fatigue.

[Eldon Goddard]

Yes that is true. I was thinking about the failure at weld lines. But I should have read more closely before saying that.