The FN P90, the fully auto version of the civilian PS90 which I bought today, is the exact gun the Secret Service uses to protect the President of the United States. And the round used in that gun, the 5.7 x 28, well the pistol which uses this caliber (the FN FiveseveN) is what British protective services use to protect the Queen of England. Those two point speak volumes as to the effectiveness of this round.
It is basically a rifle round adapted to a pistol. IMO, the next generation of ballistics as evidenced by the people who use it.
What approximate caliber is the 5.7 x 28?