Are you getting primer punctures? A couple of factory loads tend to give occasional punctures and gas could erode the firing pin face.
I replace the firing pins in my 625JM and 625PC with longer pins. I get mine from Brownell’s, but there is at least one other. The longer pin lets me shoot .45 ACP without clips for range use. The chambers seem to have been lengthened just slightly so the cartridges could run too far into the chamber to fire reliably without the longer pin.