Back in the day, when I was one of the moderators on this forum, some members were having a lot of problems with CZ extractions -- lots of stove pipes. Not everbody had the problem, but it was aggravating for those who did. This was mostly for the center-fire versions of the CZs, but it COULD happen with rimfire models, too.
If the extractor itself was not damaged, the problem seemed to be one of two things:
1) The extractor spring was not strong enough, or
2) gunk under the extractor, pretty common with cheap ammo. (Explained below.)
Wolff springs developed a stronger extractor spring, and CZ later upgraded that spring in newer models. (They sent out a number of Wolff extractor springs, too, until they had their own supply on hand.) The stronger spring seemed to solve 90% of the problems. I don't think I ever heard of a Kadet Kit extraction issue, back then.
When there was
still a problem, we found that cheap ammo is often dirty ammo, and some of the crud could work its way under the extractor, and that kept it from closing tightly on the rim of the cartridge. The junk would often work it's way out with the next round. (There's a lot of shaking and moving going on when that slide cycles!)
- Stove piping is frequently an extractor issue, because the extractor isn't gripping the rim as tightly as it should, and it loses its grip on the rim before the casing can be dragged back far enough to hit the ejector properly. That casing may slip up a bit, and be tilted into the "stove pipe" position by the ejector. Then the spent casing stays on the breech face and pushes the next round forward, or it will ride on top of the next round and be held there as the slide tries to close. Either way, there's almost always a strove pipe casing in the ejection port.
Before adjusting the ejector, try take the slide off and see if there's any junk under the extractor. That junk can keep the extractor from tightly gripping the case rim. (Just squirting some CLP or a similar cleaner or solvent or lube under the extractor -- pushing it open enough to do that -- may be enough to flush out any junk. That way you don't have to remove the extractor to check.)
I do have a Kadet Kit, which I typically run on my 85 Combat, but have never had an issue with it, after replacing the firing pin (about 22-23 years ago), which was upgraded by CZ soon after I got it. It's one of the most accurate and reliable .22s I've owned.
I suspect crappy ammo may play a bigger role in this problem than most shooters realize.
