I have a CZ 52 pistol in 7.62X25. Bought it about 12 years ago because it was so cheap. I also bought 3 thousand rounds of mil-surp ammo with it. This pistol will lock up at times. It looks like the slide is all the way forward, but it's not quite there. You can't pull the slide back when this happens. It takes a few hard raps with a plastic hammer to get it to release and eject the shell. I'm not keen on doing that with a loaded round in the chamber. I thought it might be the ammo I bought, but you can take the same bullet you've ejected, put it in the chamber, drop the slide, and you can jack that round out with out any problems. Over and over. I'm not sure where the problem is. I may take it out and it doesn't miss a beat. That's what happens most of the time. Then it might do it once or twice when I have it out. Any ideas of whats going on?