My understanding is that it picks up speed and gets close to a 357 mag dep on gun and round , might not hit it like but speed is there so . That may not be true , but 9mm will pick up a bit of zip unlike 45. I am no master of bullets. But I know that 9 mm is one handfuls of pistol stuff that does not suck in a nfa legal barrel .
BBTI - Ballistics by the Inch :: 9mm Luger Results Compared bottom to top