Firing Pins

A couple of questions:

The RGG drawings show a firing pin protrusion from the bolt face of .020.
Is this adequate from other\'s experience.

Also, do the pin tips and heads need to be hardened?

I usually grind them to .025-.028, .020 will fire most brands of .22 ammo but .028 will fire them all.  .030 plus may cause piercing and a hissing of gas will soon gum up your firing pin and extractor.  
Dick C. (gatguy)