Why, at the 800 round mark does my always trusty and extremely accurate 9UC Pro give me a failure-to-extract about 2 times per mag? Sometimes the case is left in the chamber and sometimes it is partially pulled out. It just started the last time I was at the range and I assumed that I had let it get too dirty. So I brought it home and gave it a thorough cleaning. I had it back at the range today and it still happened. I let a buddy shoot it to remove the "me factor" and it happened to him, as well. Then I remembered that I had bought a spare slide some time back (had a nickel one and also wanted a black one) and I had it in my range bag. This slide has barely 50 rounds through it so I know the extractor must be like new. Put the new slide on and still had basically the same FTEj's. Seems to me that the common denominator now is the barrel and the mags but, I don't find anything obviously wrong with any of them. Any ideas? Thanks!!