I finally got my new Yugo refurb K98k to the range today (and actually shot it!). It shot great, but wouldn't extract the fired cases. Out of 20 rounds, I think it only extracted 3. I could see that the extractor was going around the case rim as it fed, but when I pulled the bolt back after firing, the case was still in the chamber...I had to take a cleaning rod and poke them out. They didn't seem to be sticking, and everything else worked fine. Any ideas?