It has been well established that the vast majority of fluid steel 'rough forged tubes' used by U.S. double gun makers were sourced in Belgium
Winchester contracted with domestic steel makers, including Bethlehem Steel Co., and Remington (and likely J. Stevens) did produce their own decarbonized and fluid steel barrels.
Testimony by M.C. Mason of Hopkins & Allen stating that J. Stevens Arms & Tool Co. manufactured barrels domesticallyhttps://books.google.com/books?id=seIRAAAAIAAJ&pg=PA629&lpg
In American Rifleman
Nov. 1937, A.P Curtis stated in “Making Double Shotgun Barrels” that the American Gun Barrel Company of New Haven, Conn. made barrels for the U.S. market 1914-1921, but it could not compete with the duty free importation of tubes after Belgium recovered from WWI.
The cut and paste research is all herehttps://docs.google.com/document/pub?id=17ixogftgITEblNUWtmFBv96ZvgjK6eFell8GsAWd-KI
And the composition analysis of fluid steel barrels, including Dave Suponski's and other's Parker studies is herehttps://docs.google.com/document/d/1dnRLZgcuHfx7uFOHvHCUGnGFiLiset-DTTEK8OtPYVA/edit
1. Unknown date of manufacture Pieper Eclipse, likely Cockerill fluid steel - Non-standard AISI 1030 carbon steel with high manganese & phosphorus.
2. 1898 Hunter Arms “Armor Steel” - Non-standard AISI 1045 carbon steel with high phosphorus and sulfur.
3. 1908 Hunter Arms “Armor Steel” - Non-standard AISI 1018 carbon steel with slightly high phosphorus & sulphur, and a low concentration of nickel.
4. c. 1900 Crescent “Wilson’s Welded Steel” - Non-standard Bessemer (high phosphorus) AISI 1017 low alloy low carbon steel.
5. c. 1910 Meriden Fire Arms “Armory Steel” - Non-standard Bessemer (high phosphorus) AISI 1211/1016 low alloy low carbon steel.
6. A pre - WWI Parker “Titanic” barrel (courtesy of Dave Suponski) - AISI 1030 with low concentrations of nickel and chromium.
7. A pre - WWI Parker “Trojan” barrel (courtesy of Dave Suponski) - AISI 1035.
8. A pre - WWI Parker “Vulcan” (courtesy of Ron Graham) - AISI 1015.
9. A c. 1912 Lefever Arms Co. DS “Dura Nitro Steel” - AISI 1035
10. A post-WWI Parker “Vulcan” barrel (courtesy of Dave Suponski) was AISI 1030.
11. Post-WWI “Parker Steel” was non-standard Acid Bessemer Resulphurized Rephosphorized AISI 1109 low carbon Steel.
12. A c. 1925 Crescent Fire Arms “Genuine Armory Steel” barrel with the ‘LLH’ mark of of Laurent Lochet-Habran
showed it to be non-standard (high phosphorus) AISI 1040 Steel.
13. A c. 1929 “Sterlingworth Fluid Compressed Steel” was AISI 1040. Sterlingworth barrels have been found with the three-lobed crown over ‘D’ mark of Jean-Baptiste Delcour-Dupont/Canons Delcour S.A.
of Nessonvaux.Plans & Specifications of the L.C. Smith Shotgun
by William S. Brophy contains an undated but likely post-1913 Materials Specification chart indicating “AISI 1020 Carbon Steel” for both the frame and barrel.
However, under the Featherweight drawings dated Feb. 19, 1929 the lug specifies a forging of 1020 steel, but the barrel is “Steel App. 40 Carbon”, likely AISI 1040.
I've got another Smith Armor barrel to test, and may have a blown Crown steel barrel coming also. Still looking for a Nitro steel specimen.