I believe that I remember you from years ago and we have some mutual friends. Do you still have your M14 website up? You had a picture of my X006 rifle on there for years. I still have my copy of The History and Development of the M14 Rifle. The last time we spoke several years ago, you mentioned that while visiting Springfield Armory, you had been told that all the X00? rifles were made for one particular person and eluded that they were politically recognizable and wanted to remain anonymous? You would remember me as "Seacowboys".There were some M1 Garand receivers modified to accept M14 magazines and given a bolt stop by Elmer Ballance dba L H Gun Company before M1A receiver production started in the fall of 1971.
I believe I know what serial numbers X001 through X006 are (the purpose of the X prefix serial number) but I would like to get better photographs of the underside of at least one of them to confirm my suscipion.