20x102 experimental projectile (proof round China Lake?)


Does anyone know anything about this projectile?

I searched the web, and found a picture of a similar projectile on the BOCN forum
( Posted by EODGUY, answer #2 in this thread http://www.bocn.co.uk/vbforum/threads/73326-20x102mm-Examples)
where it was mentioned as experimental proof round from China Lake.

Odd on this projectile, is that the lower tail-part is thicker than normal (see pictures), so it doesn’t fit a regular sized 20x102 casing…

Sorry for the somewhat ‘larger’ pictures (i took the links for the pictures at the BOCN forum where i posed the same question)