Dr. Martin Fackler stated in article (Wound Ballistics Review, 3(1)) 1997 that the Rhino/Razor ammo was pulled from the market because it did not meet SAAMI pressure standards.
Anyhoo, if memory serves, Rhino shipped less than fifty rounds of 9mm ammo for evaluation.
The intial group fired was somewhere in the neighborhood of 8 inches in diameter. And the velocity of that first bunch varied by a couple of hundred feet-per-second.
Needless to say, the evaluators weren't very impressed.
I have six rounds of Rhino (not black rhino) in 9MM. They are constructed like a magsafe: hollow copper jacket with BB's and epoxy to fill the cavity. The cavity is really wide, and looks like they would cause feed problems in some guns. I never fired any of them, mainly because they are too hot, too much pressure.