I had a problem with my .308 FCP-K that I fixed by readjusting the pin protrusion to 0.055", I think. Mine came from the factory set a little shallow, I believe it was 0.039", which resulted in a misfire maybe 1 round out of 20 of box ammo. From what I remember, that was only 1 or 2 flats on the lock washer. No problems since.

Joe