/vr/ - Retro Games

>>3380074
Out of a rifle or carbine barrel? Not too poorly, if using original spec ammo like was intended for the FN P90 (it's a late Cold War weapon, the original idea was to easily defeat Soviet body armor). The most commonly available ammo in the US today is cheap commercial target loads which aren't too impressive compared to original spec loads (though better defensive ammo is available)

From a pistol, I'd say it's questionable. I mean, it'll probably work, but the entire point of the 5.7x28mm is speed, speed defeats armor, and that's the initial idea with the cartridge, and speed based cartridges from short barrels has never been amazing, looking at the AKs-74u or the the Mk.18 upper for the M4A1 Carbine, (5.56x45mm and 5.45x39mm are both reliant on speed, and consequently they perform kind of poorly out of a short barrel, as there isn't enough room to accelerate the bullet).

Like, it's still a gun, and it'll hurt, but you could do better in a similarly sized weapon, I'd sooner have a Beretta 92A1 with an 18rd magazine than an FN Five Seven with a 20rd magazine.
For a subgun, I might pick a select-fire FN P90 over some other weapons depending on the ammunition in question, and depending on the task.