July 11, 1903 Sporting Life stated barrels of Special Smokeless Steel were available on the Model of 1898 Repeating Shotgun, presumably the higher grades
https://digital.la84.org/digital/collection/p17103coll17/id/39596/rec/48

October 29, 1904 Sporting Life
https://digital.la84.org/digital/collection/p17103coll17/id/37487/rec/10
Marlin Special Smokeless Steel available on the Model 1898 Grade C Pump: tensile strength 100,000 psi with a very high elastic limit.

The Marlin Model 16 (16g) and Model 17 (12g) Repeating Shotguns were introduced in late 1904
12-1-1904 Shooting & Fishing
https://books.google.com/books?id=EZMwAQAAMAAJ&pg=PA150&source

Marlins Model 19 Take-down shotgun was introduced in 1905; A, B, C, D, Trap, Brush & 16 gauge
October 21, 1905 Sporting Life
https://digital.la84.org/digital/collection/p17103coll17/id/36469/rec/13


Still looking for a chunk of "Special Smokeless Steel" to test

https://sites.google.com/a/damascusknowledge.com/www/home