How many different barrels are there?

[Mills]

Hopefully Drew Hause will chime in here. He knows more about old barrels than anyone. I will say Dean's list looks pretty complete.

[Drew Hause]

Probably more here about them new-fangled fluid steel barrels than you want to know, including tensile testing and composition analysis (the Parker barrels courtesy of Dave Suponski). Scroll down to the bottom for a summary
https://docs.google.com/document/d/1...EK8OtPYVA/edit
and
https://docs.google.com/document/pub...eFell8GsAWd-KI

Maker's could call barrels whatever they wanted, with creative assistance from the Marketing Dept. and it is very likely that the same Belgian sourced tubes were used by most of the U.S. gunmakers.
The ‘LLH’ of Laurent Lochet-Habran has been found on 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, L.C. 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”.

The "Creative Naming of the Same Stuff" prize probably goes to the Hunter Arms Fulton Tradename guns: “Royal Steel”, “Special Smokeless Steel”, “London Fluid Steel”, “Peerless Steel”, “Fluid Blued Steel”, “Projectile Steel”, “Silver Steel”, “Blue Diamond Steel”, and “Missabe Fluid Steel” on “Comstock Arms Co. Duluth” guns.

Modern Chrome Moly 4140 was developed in the 20s for automobile axles and eventually became the standard shotgun barrel steel.

Pattern Welded barrel nomenclature is even more confusing
https://docs.google.com/document/d/1...TWH8vv0fE/edit

[6pt-Sika]

Fluid steel damascus steel or steel twist "I" classify them in in two groups . SAFE and UNSAFE .