I purchased 2 CZ 82s a few months ago, and love the guns. I've refinished one
http://www.czfirearms.us/index.php?topic=42128.0 and left the other one stock. I was firing the unrefinished pistol when the trigger guard broke, which appears to be a common problem.
The refinished CZ 82 developed the single action "decocker" problem, where pulling the trigger in single action causes the trigger to fall into a double action type movement, allowing the trigger to be dropped slowly if the trigger is released slowly. This was not present before I sent the gun in for refinishing, but the problem presented itself after I received it.
I swapped lockwork parts here and there between the two pistols, and I learned a few things:
1. The trigger sting mystery: It appears the trigger sting mystery is related to the hammer lever (parts diagram here
http://www.okiegunsmithshop.com/CZ_83.jpg). My unrefinished pistol was a "stinger", but my refinished pistol was not. When I placed the "stinger" hammer lever into the non-stinger pistol, it developed a nasty case of trigger sting. When I placed the non-stinger hammer lever back in the gun, the trigger sting was gone! A new hammer lever is only $18 from the CZ store, and it might be a worthwhile investment for those of you with the trigger sting problem!
2. The "decocker" mystery: I've seen multiple posts about this issue, and I experienced it after receiving my refinished gun as well. I noticed this happened more when I shot the gun left handed, and it turns out that if I applied pressure to shift the trigger to the left while I pulled it back in single action, I could reliably cause the "decocking" behavior. After looking at how the trigger bar, sear, hammer lever, and hammer interact, some things are clear. The sear has nothing to do with the double action pull of the trigger and hammer. Once you pull the trigger, the sear disengages (rises) and has nothing to do with the double action pull. In fact, I took out the sear and was still able to make the hammer fall with a double action pull. Therefore, the double action pull depends on the interaction of the trigger bar, hammer lever, and hammer. I tried swapping out the hammer lever (hence the solution to the trigger sting mystery above), but swapping out the trigger bar fixed the undesirable "decocker" action. This makes sense, as applying torque to the trigger caused the action. So the cause of the "decocking" problem appears to be a faulty trigger bar/hammer lever interaction. The sear releases the hammer, which caused the hammer lever to catch on the trigger bar and drop the gun into double action. I might think the disconnector is faulty here too, but I fixed the problem without doing any modification to the disconnector.
In any case, I think the safe play for either of these problems would be to replace both the trigger bar and the hammer lever. I wish I could tell you more about the wear and tear on these parts, or the engagement surfaces, but I'm definitely not a gunsmith.
Good luck!
