5.7x28 is the round that the FN P90 fires and also the "FiveSeven Pistol" both are made by FN. The loaded rounds are from about .50 to $1. It's a "LEO only" weapons system. No idea why, looks to me like its not all that much more than a regular SS109.
'Course ya can't get a semi auto pistol thats the same size as a normal 9mm in .223.......lol
More than one thug has told me that the only thing he really fears is an armed victim. Not police, not jail, not a jury. An everyday person with the means and ability to NOT be a victim.................