I had the same problem, no matter how I tried I couldn't get an unfired case out of the chamber with out a knife blade or a flat head screwdriver.
Then I started looking really closely with the bolt out of the rifle. I noticed that the extractor doesn't make contact with the rim of the case when the bolt is closed. I extrapolated that you have to fire a round, then the case pushes back on the bolt just enough that the extractor can engage the rim of the case as the blowback action pushes the bolt back which cycles the action.
I took my dremel to the cut in the side of the chamber where the extractor sits when the bolt is closed.
I removed just a hair of material, enough that when the bolt is closed the extractor can grab the rim of the case.
Problem solved.
Cheers!