Because of the Labor Day weekend, I didn't get around to picking up my 646 until today. Oh Happy Day!
Soon as I got home I pulled the grips and noticed how the strain screw had backed out and may have cause some of the light primer strikes the previous owner eluded to, with the thicker Rinz type moonclips he gave me.
I will hold off installing the Cylinder & Slide extended firing pin, until tomorrow, when I will put 100-200 rounds through, using primarily Ranch & the Rinz moon clips.