Hey guys, I'm back. Once again, my computer was being used as a "Host" and finally locked me out. My computer guy from IBM made it whole once again!
So, anyway, playing catchup here now.
This condition is caused by extensive shooting of the R9. That "rib" is caused by the slide going backward after you fire a round and it pushes the hammer back at that time, which is what helps with the timing and recoil absorption of the R9, along with the other two springs in the recoil assembly, making a total of three springs to handle that job function. That is wear on the slide firing pin retainer area from shooting. Now there was an issue for a short time of the firing pin retainers being too thin, but in spec, and the area of the slide where they went, also in spec, but at opposite ends of each other, hence the term "Stacking of Tolerances". The fix for that was done by Karl or I at the factory by using a punch to peen over the area to hold the firing pin retainer in place. To remove the retainer, all that is required is a flat punch to fit inside of the firing pin hole area of the retainer and hit it downward while the slide is sitting firmly on a work bench. It will come out that way, that's how I got them out for servicing.
Hopefully you all understand the process now.
Nice to be back again!
Regards,
Eric R.