Like the other folks said, it's an FN P-90. Yep, they make a civilian/semi rifle, not likely to be available in a pistol version because of the pretty-much integral buttstock. However, you could legally cut one of the rifles down to a P-90 length short-barreled rifle after doing the fed paperwork and paying the $200 tax.
You'd still be stuck with the kind of puny 5,7 FN cartridge, which I played with for a couple of years in a modifier AR-15 conversion version. Or, you can *dress* a Ruger 10-22 rifle using airsoft P-90 parts or one of the MUCH more expensive Red Jacket P90/10-22 conversion kits, or one of the circa $300 Aklys Defense ZK22 10-22/P90 kits [which is how I'd go.]
