From The Gun and Its Development WW Greener 1907

Quote:
Of the steels used for shot-gun barrels, the best known is Whitworth's fluid compressed steel. This is a cast steel; the ingot whilst in a liquid or a semi-liquid state is submitted to pressure, with a view to eliminating blow-holes. The top and bottom of the ingot is cut oft" and thrown aside as usual. Eminent metallurgists contend that in the process of cooling the contraction of the ingot is so great that o pressure which can be brought to act upon it by mechanical means can affect the metal—at any rate, beyond a few inches from the surface. The process is therefore by some regarded as quite superfluous. On the other hand, it is generally allowed that the Whitworth steel is of excellent quality, and it has been used for barrels for so many years that its suitability for that purpose may be taken as fully proven.

The Whitworth steel is to be ordinarily distinguished from other steels by its brand, and by that alone. This mark is a " wheatsheaf," and London gun-makers who have sold guns with these barrels for many years now have their barrels with this registered trade mark stamped on the under side and the ordinary lettering " Whitworth's steel," etc., on the top of the barrel or the top rib. Whitworth steel is higher in carbon than many steels used for gun barrels, but it is sufficiently ductile to allow of drilling.

Steel made by the Siemens-Martin process has been used successfully for shotgun barrels as well as rifles. So, too, tubes of basic open hearth steel, made from hematite pig and scrap, and carburized by Darby's filtration process, were tested at the Birmingham Proof House in the trials already referred to and obtained a high figure of merit

Steel barrels may be made by drilling them from the ordinary rolled bar; they may be drawn by rolling out pierced blanks; they may even be rolled hollow by the Mannesmann process, or they may be forged, then drilled.


Pete