Peter Makes A Good Point
Has anybody, including Mr Ackley of past, ever performed a chemical analysis of the actual steel that Germany used in the manufacture of Mauser Actions.
You can case harden, or carburize, any steel, including 1018, but it lacks the alloy content to respond to a true "heat treat", as in increasing, (improving), the physical properties.
Performing a "heat treat" on any steel without knowing the true chemical content is simply guess work, and borderline iresponsible. Sure, it might show a harder Rockwell C number, but that doesn't mean you made it stronger........jackie