5.7x28mm 

A premier calibur invented by FN (Fabrique Nationale) for two of their premier firearms : the Five-seveN and P90.
It is compact, yet powerful like a rifle round (able to pierce armor).

5.7x28mm is also illegal for citizens to possess because of its armor-piercing capabilities.

5.7x28mm by Dave February 1, 2004

5.7x28mm FN 

A small bottleneck cartridge developed for Personal Defence Weapons by Fabrique Nationale Herstal. Mainly used in the FN Five seveN and the FN P90 PDW's. Even though it has less recoil than a 9x19mm Parabellum round, it is capable of defeating medium ballistic body armour. Superior to the 4.6x30mm HK cartridge according to a NATO evaluation, but not standardized due to Germany and several other countries rejecting it.

They thought they were safe because of their ballistic vests, but our P90's firing 5.7x28mm FN rounds proved them otherwise.

5.7x28mm FN by Ashirg April 14, 2020