Need input on 5.56 unknowns

I am looking for help or input on these two F C 6 4 dummies. Bill Woodin has them also, but has no information with them or any idea what they were for.
I have had some input from various collectors who have called them: function testing dummies, range dummies, or possible short range load test loads.
No one at Federal Cartridge remembers anything about them. So guys, any thoughts would be appreciated.

Try Ron Fuchs’ excellant reference book. If he doesn’t know, nobody does.


Are these unfinished cases with projectile jackets stuffed in the wrong way?

Ron, only notes that these two items are “Dummy-Short Range” and that they are in Bill Woodin’s collection.

I examined the projectile jackets with a small light and when one looks into the openings there is no base to either jacket. One can see through into the entire
case of each round. The jackets appear to be seated about three quarters of the way down the neck of the case. I wonder if
These could be a couple of pieces from the draw of a copper jacket bullet that some one just put into two FC 64 cases and
now we wonder what the heck it is 50 years later.