did that check and can feel no grittiness at half-cock,
Well, if you can't feel it, it probably isn't hitting it.
But it's not "grittyness".
More like a little "tick" when the half-cock notch pushes the sear out of the way when you let it down by hand.
Is your bur running all the way across the sear?
Or just in the two ends where the full-cock notches engage?
If it's all the way across, it has to be the half-cock notch hitting the sear due to one or more of the following:
* Trigger stop adjusted too close.
* Hammer hooks cut down too far.
* Hammer half-cock hook not in spec. (Hook too thick)
If the burs are only on the outer ends where the full-cock notches engage the sear:
* Soft sear.
* Or,
the firing pin stop is an EGA over-sized
* Did you radius the bottom edge of the EGA stop?
(just went back and looked at your picture in post #32. Edge is still square!)
If it is still very square like they come, the hammer is being dropped suddenly with full force on the sear as the slide / FP stop clears it.
That might whack the sear edge hard enough to raise a bur on each side.
I don't know.
Tuner?
PS: Have you considered getting an Old Priest and a Young Priest to take a look at it?
rcmodel