It looks to me like it has been covered in the first couple posts of this thread.
As Stuart notes, the original spec was replaced with SAE-AMS-M-7866 and it is a molybdenum disulphide lubricant. A search for lubricants that meet that specification will get you several hits. One of the NSNs appears to be 6810-00-816-1025 and that as well could lead to several hits.
Here is a (expensive) example of one source:
http://www.skygeek.com/molykote-z-po...der-283gm.html
Below would be a good source at a reasonable price. Where else but ebay:
http://www.ebay.com/itm/1-LB-MIL-M-7...-/252042122222