Does anybody know for sure exactly WHAT SURFACES are "surface hardened?."
I've got a feeling that the ONLY surface that may be surface hardened is the face edge of the trigger.
I've got a feeling that the hammer and disconnector are not surface hardened at all.
Everybody raves about Bill Springfield's work, and I have every reason to trust his reputation.
But, take a look at the edges he modified, and explain this in the context of "surface hardening."
Here's the link to a bunch of pics:
You will see the surface-color difference on only the trigger.
http://www.ar15.com/forums/topic.html?b=3&f=118&t=456282
I can't vouch for the origin of the parts. They are take-offs from a "parts-gun" I bought from a friend.
Here's a pic of the hammer.
(Since Bill worked on the set these parts have not been installed or tested in any of my equipment yet.)