Possibly contributors could step up and suggest what the steel WAS rather than what it was NOT? What other options were there in 1926 when Winchester Stainless Steel was introduced?
I'm actually more interested in which Winchester DOUBLE BARREL shotguns ever had stainless steel barrels? I have never seen a Model 21 or Model 24 with stainless steel barrels. Were any ever made?
I can't understand why Miller's comment pertaining to the near certainty that 304 stainless was not used presents a problem. There has been a lot of sheer conjecture and guessing about barrel composition in this thread, and the other threads about Marlin or Remington barrel steels.
For example, the frequent reference to Bessemer steels covers a vast amount of ground. First off, it is pretty unlikely that any of our American gunmakers utilized barrel steel from actual steel mills in England that were operated by Henry Bessemer. The majority would most likely have been used in England.
Most of what is referred to as "Bessemer Steel" is steel that was produced under license by dozens of mills that paid for the rights to use the Bessemer Converter Process to make steel. Early Bessemer process steel was often junk, and Henry Bessemer was forced to pay back a lot of money to mills that weren't able to produce a quality product using his patented methods. Bessemer himself tried thousands of different recipes and methods to try to perfect his steel, without much success. And it was Robert Forester Mushet who also tried thousands of different experiments who finally perfected the Bessemer process, but ended up relatively poor after losing the patent rights.
And there have been literally hundreds of thousands of heats produced over the years that would have a wide range of metallurgical compositions. Bessemer Converters were fast, but did not permit nearly as much time for testing as later processes such as the Open Hearth. Metallurgical testing also was not nearly as precise, cheap, and easy as it is today either. Nowadays, the composition of a heat from an electric arc furnace is even modified or adjusted after it is removed from the furnace, by LMF refining. Even the equipment used to CNC mill test samples for exact precise cross sectional area for tensile strength testing was not available 100 years ago. There has been much discussion about the steel that was used in the hull of the Titanic that caused the iceberg to break it instead of merely bending and deflecting. When you, or a ship-maker, or a gun manufacturer buys steel from a supplier, you don't necessarily get exactly what you order. This is one reason that European gun makers are required under law to do Proof Testing of finished and semi-finished barrels. This was even tougher back when hundreds of mills were competing using slightly different processes, equipment, and alloy mixtures. Minor differences such as a different type of coal used to make coke could change the impurities content and analysis of the steel. And this is why Whitworth steel barrels got such a good reputation... because they exclusively used their own product made by their own people.
I'm sure Miller could attest to the fact that two or more samples of the supposedly same steel could have a range of percentages of ingredients, and a range of properties. I'm certain he could verify that different batches of steel, say 4140 for example, can and do have slightly different hardness and machining qualities when it comes to cutting, milling, drilling, and threading. Variations can occur later during rolling, annealing, etc. Because of this, a single sample of steel taken from a barrel of a 1930's Model 12 may not tell us much at all about the steel used in millions of other Winchesters made over decades of production.
It's a fascinating subject going back to a time when steel was more valuable than gold, but I'm afraid that generalizations based upon analysis of a few samples of barrel steel are never going to be definitive.
