Or a Czech Vz52. While resident in Memphis, my usual truck gun was a 7,62mm Mauser C96 *Broomhandle* pistol, since the carry of a loaded rifle or shotgun was a violation of TN state law, but even with stock attached the broomie was legally and technically a *pistol.* The addition of a 10-round magazine extension, which gave me 20 rounds without reloading [and better, allowed me to top things back up with a 10-round *stripper clip* charger once my ammo tank was half-empty] improved things even better still.
And, if penetration of ballistic vests is the name of the game, the purpose for which the FN 5,7 was reportedly designed, the 7,62x25 Tokarev cartridge has another possibility that might interest you:
Also, if you don’t mind cleaning up after firing corrosive ammo, 7.62X25 is one of the last milsurp “deals” out there in a viable combat round.
With 5.56 etc costing way north of 50 centavos a pop, ammo for your Tokarev or CZ52 at 11 cents a round looks better and better.
Get it while it lasts, folks. Those big Bulgarian ammo cans won’t be around forever, especially if a ‘rat wins in 08 and bans imports.