Quoted:
While trying to diagnose some ejection problems, I disassembled by A2 buttstock to check the spring and buffer, something I never did before.  I noticed buffer tip, where it meets the metal casing, had a flange of thin plastic sticking out around it in diameter of 1/16 to 1/8 inch long all the way around.  It looked like it was never cut properly during the manufacture.  I shaved it off, and I noticed a difference.  When pushing the buffer/spring into the tube, it would move freely, sort of hit some resistance and move again every so often.  I thought this was normal and was the long spring twisting around in the tube.  After the circumcision, it runs smoother when pushing in the spring.  I already installed a new extractor and spring.  My extraction problems seems to have gone away.  

Could this flange of plastic been binding the spring while the spring compresses over the flange (if that is possible), causing enough static friction to contribute to a short stroke?