Took my RPD out today for the first time since last summer. Fired about 40 rounds out of 100 and then "click" followed by manually chambering several more rounds, only to hear more clicks. Then I looked at the ejected live rounds. They all had either a very light strike or no indentation at all. I checked the screw in the back of the stock that's accessible by the cleaning kit trap door but it was tight. What could be causing this? Ammunition was Red Army Standard made in Ukraine.

I think you're on to something. Upon disassembley, this is what I found. The pin securing the firing pin extension fell right out and is obviously deformed. Where do I go with it from here? Is there a commonly accepted effective remedy? RPD gunsmithing is very uncharted territory for me. Despite the pin clearly being separated from the bolt carrier, the firing pin extension is remaining in place. It moves forward and backward enough that it can be flush on either end, but does not come out. Is this normal, or is it mushroomed in the channel enough that it's no longer removable?

I'm looking at it like an AR15 firing pin, which comes out after the pin is removed. In this RPD case, the pin has been removed, but the firing pin extension remains in the bolt carrier. Shouldn't it have fallen with the cross pin removed?

You're probably right. But just for something to do, I went and bought the closest thing to a replacement to the retaining pin I could find at the hardware store. I also picked up some sandpaper. Managed to use a punch to remove the firing pin extension and smoothed it out a lot with the sandpaper. Now with the new retaining pin and smoothed out firing pin extension, there's no grittiness or hang up whatsoever. I'll probably try to make time tomorrow to take the RPD out and see if this fixed it. Appreciate your help. Mentioning the firing pin extension got me on the right track.