This thread reminded me of a round that was given to me back in the 80's.
It appears to be a standard 5.56 brass, topped off by what I was told is a ceramic bullet
The bullet is a flat nose, (like ball, with the point clipped off) and appears to have been manufactured that way, as it seems to have mold marks on the exposed end.
I was told at the time that it was part of a government program to field a new round for Spec Opps, but I have no idea of the veracity of that, and really don't know what it is made of, other than it obviously isn't lead.
If anyone has any information on this round, it would be interesting to me to find out it's intended purpose.