I'm inclined to think the "Wonder" barrel dates to 1950's. If it were between 1897 and 1923 and proofed in Saint-Etienne, the chamber would be "6.5" not "65."
FAB500 further identifies the trademark "Wonder" as being from Paris - "Wonder" marque déposée par René Cosson. In this context there are René Cosson hunting catalogs posted from the 1950's-70's. Nevertheless, "Wonder" is not mentioned in the catalogs so I'm also not sure He ever actually marketed a "Wonder" gun let alone a "Wonder" barrel. So it's possible the mark was indeed used pre-war.
Re the "métal St. Chamond spécial" stamp: In the line referenced above on my "Wonder" shotgun, another shotgun is posted with the "métal St. Chamond spécial" stamp (not pictured in the ad). Google AI notes: "métal St. Chamond spécial" refers to a proprietary high-strength barrel steel used in French double-barreled shotguns (fusils de chasse) manufactured in the arms-producing hub of Saint-Étienne during the early-to-mid 20th century." It further notes ""Metal St. Chamond" references steel output associated with the heavy industrial and steelworks company Compagnie des forges et aciéries de la marine et d'Homécourt, located in nearby Saint-Chamond."
My wife's father hails from Saint-Chamond where his family ran an aircraft parts business for 50 years.
By the way per above I'm still not convinced that Wonder shotguns were the product of René Cosson. Ravat made a trademarked best selling bicycle for years during the 1920-30's trademarked "Wonder." However, the "W" on the above Wonder barrels is different from the "W" on the key of my Wonder. Wondering why.
![[Linked Image from jpgbox.com]](https://www.jpgbox.com/jpg/51945_600x400.jpg)