Italian wildcat?

I was at the local shop, and the gunsmith was talking about a tour he took of one of the Beretta factories in Italy. They had a little range session as well, and he got to shoot all kinds of fun stuff. He said that in the range next to him, a guy was shooting something they were coming up with for military applications. It was a 20mm necked down to .50cal. He said you could almost SEE the shock wave every time the guy squeezed the trigger. Anybody else heard about this? That would definately be interesting for prairie-dogging :shock: !