And steel is entirely unsuitable for gun barrels!
The Amateur Sportsman, Gun Barrels Past and Present, April, 1911
https://books.google.com/books?id=m5kXAAAAYAAJ&pg=RA5-PA12&lpgJames D. Dongall, 59 St. James St., London, wrote the following:
Shooting: Its Appliances; Practice; and Purpose, 1875
https://books.google.com/books?id=-ToCAAAAQAAJ&pg=PA15&lpg No barrel of steel, pure and simple, thin enough for a fowling piece could be made unless at such an expense as would be absurd, and then would be unsafe. Pure steel barrels, being chrystalline, once strained, lose all of their safety at that part. Their molecular structure has become quite changed and been irreparably injured, so that final bursting is only a question of time.
Metal for Gun Barrels, D. Kirkwood, Boston
(In 1874 Henry & David Kirkwood started the Mortimer & Kirkwood shop in Boston, Massachusetts. In 1881 the partnership was dissolved, and the name of the business was changed to David Kirkwood, Gun and Rifle Maker.)
Forest & Stream, January 14, 1875
https://books.google.com/books?id=EjUaF7Y1k90C&pg=RA2-PA362&lpg In the question of steel vs. iron in gun barrels, I would contend thatsteel is unsuitable, from its greater liability to friction, its inability to stand severe or sudden strain during a low temperature, and it would be nearly impossible to expect steel to be worked up into the highly figured barrel now used, as is the case with iron, without disintegrating or disturbing the molecular aggregation of its particles. The numerous operations which it has to undergo, and at a high heat rob it of the very carbonization which constitutes its main feature
Replies, February 4, 1875
https://books.google.com/books?id=EjUaF7Y1k90C&pg=RA2-PA411&lpg 
