I've seen that prototype round. The case is 10" in diameter (at the base) x 2.25" long....firing a 7 grain, 1.2 mm bullet (0.050", to be exact). It's called the .05 WSSSSSSSSSSM. Quite a scorching round. Requires 16,100 grains of powder, for a normal load. Alas, however, they are having problems with it. First, as roy said, the scope rings have to be rather high. Next, the receiver is a bit bulky...at least in width. Resizing the case is a bit tough with a hand press. Extraction and ejection is a bit of a problem. Finally, the recoil is just a bit on the stout side.
Oh well, they'll sort it out. Can't wait to get one.