Scott: sorry for the qualifier, but no one can tell you if
your gun is safe, and certainly not without knowing the wall thickness at the end of the chamber, the forcing cones, and every inch of the first 12" of barrel.
Quite a bit of information about 1/3 down here regarding Decarbonized/Bessemer Steel
https://docs.google.com/document/d/1...EK8OtPYVA/edit
Short version is that the tensile strength was greater than pattern welded tubes, and the "Parker Steel" used on Grade 1 PH & NH after 1917 was Decarbonized Steel.