I have a newer model Model 39a that would fail to extract fairly often. After reading tons of material pointing toward the extractor, I found it had absolutely nothing to do with the extractor after all. I examined the situation with a magnifying glass.
I found the problem to be with the cartridge guide spring. Sometimes the smashed edge of the case rim would find its way into the small gap between the chamber and guide spring. You'll know this is happening when you can tap it with a cleaning rod or pry the edge and the case won't move. I would have to push up on the spring toward the receiver roof to let the case free.
The fix: I removed my scope and mount rail so I could get at the guide spring screw in the top of the receiver. I tightened the screw a bit and it solved my problem.
I don't know if the previous owner loosened the screw thinking it was a filler screw for the scope mount, whether it was set wrong from the factory, or if it came loose after two years of light use.
Basically, a hair adjustment can make all the difference in the world with this problem. I don't know how many are out there like this but its not always the extractor.