Whitworth steel barrels appeared in 1875:
Whitworth fluid compressed steel was invented by Mr. Joseph Whitworth, who we already talked about when discussing polygonal bore rifling and the Whitworth rifle. Mr. Whitworth was the eminent mechanical engineer of his day and came up with a way of producing a stronger cast steel. His process consists of melting a steel ingot into a mold and applying pressure of up to 6 tons/sq. inch to the mold while the steel is in a liquid state. The pressure drives out all the gases and eliminates blowholes in the cast steel. It also increases the density and strength of the steel. According to W.W. Greener's book, The Gun and its Development, with the introduction of choke boring in shotgun barrels, whitworth steel was found very suitable for this process and started replacing damascus barrels, and he mentions in 1875, "Whitworth steel was giving great satisfaction for rifle barrels, a leading London gun-maker adopted it for shotgun barrels." The leading London gun-maker was Purdey & Sons, who used Whitworth steel exclusively for years after that. Use of Whitworth steel for gun-making spread to America as well and well known makers such as Parker, L.C. Smith and Lefevre were making guns using this steel, way into the 1930s.This DGS line discussed it in 2007...Whitworth patented his compressed steel in 1874; 1st Purdey with Whitworth barrels delivered 1 Jan 1880, ordered 3 years previously.
https://www.doublegunshop.com/forums/ubb...&PHPSESSID=And by the way, the French symbol on Ronchard Cizeron's barrels in late 1890's "Acier Comprime" is directly translated from from the Whitworth patent:
This line:
https://www.doublegunshop.com/forums/ubbthreads.php?ubb=showflat&Number=486642&page=6
