The FN-P90

More info and a demo video by blackfox herself, in the members area!

Caliber: 5.7x28mm SS190 
Weight: 2.54 kg empty; 3 kg loaded with magazine with 50 rounds
Length: 500 mm
Barrel length: 263 mm
Rate of fire: 900 rounds per minute
Magazine capacity: 50 rounds
Effective range: 200 meters