A Kimber M82 in 22 Hornet was recently brought in due to very poor extraction. The chamber is clean & nice & smooth. The extractors appear to function properly but lack any ability to extract a fired case--both Hornady factory & very mild HLs. It appears that this is a converted rimfire action and that the flimsy, clip type spring that holds the extractors in place is just not up to the task. Is this common with Kimber M82 Hornets or have I completely misdiagnosed the problem?

I had a Kimber 82 hornet that had that issue. It would extract about 50% of the fired cases. I was using Winchester cases.
Someone told me to try RWS cases and I found some at a gun show. That gun extracted 100% of those RWS cases. Not sure why but that made a difference.

I have a Kimber 82 in 22 k-hornet and 2 more in 17 K-Hornet. All of these are factory k hornet guns. I have never had any problems with extraction on any of them. They all hold the case firmly with the 2 extractors. You might try another extractor collar. Also do both of the extractors fit solidly over the rim of the cartridge?

We had that problem sometimes back when we did Kimber warranty. If I remember correctly. The extractors were cut to shallow and they wouldn't quite go over the rim when you closed the bolt. Felt pen the rim of a case and insert it into the chamber and then close the bolt slowly and then open it. Carefully knock the case out with a cleaning rod and observe if the extractor actually went over the rim. If not, pull the extractor out and put it into the mill and swipe off .005 inch from the back side with an end mill or woodruff. Then try it again and keep it up until it snaps over the rim.

Thanks for the comments and recommendations. I'll let you know how Rod's suggestion works out.