Ok, facts are facts: The 1916 Spanish Mauser is arguably at the bottom of the heap for use as in a custom Mauser sporter. I understand the emotional attachment to these actions of the OP's, and if they were mine I would polish them up, blue them, and mount them on walnut plaques with brass nameplates saying where they came from and who owned them. Then take the money saved and apply it toward more deserving projects or rifles and then use them at an annual "Remember XX Old Friend Memorial Shoot". I bet He would smile at that.
A 1916-based sporter in the end is just, well, a 1916 Spanish Mauser.
This
