Just found a 1975 vintage reference to the 7.62mm XM256E1

The May-June 1975 issue of “Infantry” magazine notes a recent demonstration of the 7.62mm XM256E1 Ball load at Fort Benning. Frankford Arsenal’s Andrew Grandy and Walter Squire are promoting it as a companion to the M14 rifle modified with a wacky top-folding stock. (As many of you may remember, Grandy was the same fellow behind the “folded ammunition” concept.) It seems rather odd that Frankford would be promoting the load so many years after it was originally developed.