Re. hinge pins made from high carbon steel.
One gunmaker from Ferlach shared his experince for replacing hinge pins. He pushes out old hinge pin, then presses barrels to receiver and reams new hole with tool is a bit larger diameter, than old hinge pin. Then he cut the reamer tail and use this piece as new hinge pin.
As you know reamers made from HSS steel and this sreel is high carbon one.
I used this method several times and found it very easy and effective.

Geno.