and just to emphasize earlthegoat2's directions,
the ejector rod is "reverse-threaded." Be sure to put at least two-three empty cases in the chambers to help relieve stress on the extractor. See the sticky in this forum for disassembly / assembly directions.
I'd use those directions to get the cylinder out and disassembled and then do a complete cleaning of all the cylinder parts. Make sure the extractor and shaft are clean, as well as the cylinder recessed machining for the extractor. On reassembly, reinsert the empty cases, and when you tighten the ejector rod, use a parallel-jaw pliers (if you have one). With any pliers, pad the jaws; I use a patch doubled-over.
If you still have binding problems, diagnosis and repair are probably beyond typical novice-home gunsmithing skills, so look to a good 'smith for further work.
Jim H.