Originally Posted by dhgeyer
....... The rub marks on the EDP has been noticed and discussed in other threads. I don't know if there is a consensus on this (what causes it and what it does), but I have my opinion. It happened to mine also. I noticed it after JSB pointed it out in another thread. My gun had about 500 rounds on it at that point. I can't say when it would have become visible had I been watching for it. I attribute this wear to a sharp edge on the front of the extractor assembly channel in the slide and the hardness of the slide. In my gun the original EDP is a loose enough fit in the channel that I would rule out binding.
JSB said that he has seen guns in his shop that had wear in this location that would almost surely impede steady tension on the extractor. I think that might be one small piece of the puzzle of why extraction/ejection can go bad on these guns after X number of rounds.
Well, there IS an alternative explanation!
I am positive that the EDP rod is NOT striking (or, 'nesting') up against the exact same place on the back of the extractor every time. I think, but I cannot prove, that the extractor's, 'pivot pin' and the hole in the slide it rides in are also involved. Furthermore I believe the excessive vertical, 'slop' between the slide cutout, and the extractor's top and bottom, 'flats' has something to do with all of this.