I didn't want to interrupt another thread but was curious about the following comment posted.
"The best thing I have done to mine is to polish the everliving crap out of the bolt and carrier. That dramatically improved reliability for me and got rid of the "crunchy" feeling mine had when cycling the action."
I've not done this to my pre-XN gun and don't remember this mentioned before on any forum, but wondered if others have polished their bolt and carrier.