Thank you.
It would not be a surprise if the barrels carry the 'LLH' of Laurent Lochet-Habran. The mark has been found Fox, Baker, Lefever, Crescent, Ithaca (Lewis & Flues with Smokeless Powder Steel), NID, Lefever Nitro Special, Lefever M-2 single barrel, and Westernfield Deluxe/Western Arms Long Range, Smith Royal, Armor, London, Crown and Nitro barrels and Hunter Arms Fulton and Ranger for Sears. Baker guns may be marked Nitro Rolled Steel and Folsom Crescent guns Fluid Temper Steel.
Composition analysis by Optical Emission Spectroscopy (OES) of a 1908 Hunter Arms Armor Steel barrel showed the sample to be non-standard AISI 1018 Carbon Steel with slightly high phosphorus & sulphur, and a low concentration of nickel. AISI 1018 tensile strength is about 60,000 psi.
The 1918 Sears catalog states the Hunter Arms Fulton Gladiator (very likely by LLH) barrels are made of a high grade carbon steel, having a tensile strength of 85 to 95 thousand pounds to the square inch.
A 1919 Ithaca barrel sample (unfortunately without indication of the barrel type) was AISI 1030 with a reported tensile strength of "about 70,000 psi".
A c. 1925 Crescent Fire Arms Genuine Armory Steel barrel with the LLH mark showed it to be Rephosphorized AISI 1040 Carbon Steel with a Tensile Strength of 104,000 psi - very good stuff.
So bottom line again: the Imperial Steel barrel is likely of the same (good) quality as that used by the other U.S. makers.
And the steel used to fabricate barrels by Jean-Baptiste Delcour-Dupont/Canons Delcour S.A. & Laurent Lochet-Habran was likely sourced from Acier Cockerill Manufacture Liegoise. Manufacture dArmes Feu Ligeoise used Cockerill steel almost exclusively, and also labeled the steel Acier Special and Acier Excelsior.
It seems likely that Krupp licensed Cockerill Sambre, as Fluss Stahl Krupp Essen marked tubes stamped with Acier Cockerill or with LLH of Laurent Lochet-Habran are found on some U.S. maker's barrels. LLH was also licensed to manufacture barrels marked Siemens-Martin.
