It sounds as though the ejector spring may be the culprit. Check to insure that the ejector plunger has good tension on it ans moves freely.
Check the Bolt to insure that the key is tight and mates correctly with the gas tube.
You should also check to insure that the gas port is present and free on obstruction.
(Don't laugh, a National Match M1A was shipped by one of the top guns to a fellow who brought it to Bruce Woodford. Complaint: wont't function. Diagnosis, no gas port drilled in barrel!)
Finally, I am not familiar with the CAR version, is it possible that an incorrect spring or buffer is being used in the CAR?
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Ni ellegimit carborundum esse!
Yours In Marksmanship
http://www.1bigred.com/distinguished
michael