My offhand recalled reference to Santa Barbara category actions "soft", relates to the Golden State Arms branded "Centurion Mauser"; generically Santa Barbara action. The encyclopedic work "Bolt Action Rifles" by Frank de Haas, @ Page 305, references a Rockwell hardness test result reported to the author. YRead the comment at the bottom right of that page (also shown confusingly as Page 306). A generally comprehensive review of the Santa Barbara mauser occurson the following pages.

https://archive.org/details/Bolt_Action_Rifles_3rd_Edition/mode/2up

Reading hint: This reference is available free, but the navigation involved in reading & pagination, is sadly weird. Navigation clue: The cursor control for reading doesn't work as conventional "push & hold to navigate" Rather like an "on-off" switch. Push & release to engage and remaining in navigation mode until push & release to disengage!

Good Reading!
John