Using one of these pellets, a 9mm round from a 6 ft/lbs pistol would be travelling at roughly 187 feet per second - about the same as your average springer airsoft pistol, but with a much better ballistic co-efficient.

It would probably be a realstic possibility for close (below 20 feet) range ratting. Then again, using a 20 grain 0.25" pellet at about 365 feet per second sounds like a better compromise.