I might add specifically that Winchester's current production "LE-only" Ranger 147gr round is pretty subsonic, and is considered one of the best hollowpoint defense rounds by just about everyone to boot. The model number is "RA9T" - there are many other variations from Winchester with "Ranger" and/or "SXT" and/or a "T" (for Talon) in the name / model, but I'm referring in this post specifically to model RA9T. Winchester only sells it to LE, but it's perfectly legal to own by federal law (check state laws). It can be hard to find a source, although it does pop up at gun shows and auction sites sometimes.
(Edited to add the specs from mfg):
RA9T 9mm Luger 147 grain T Series
Velocity at Muzzle, 5yards, 25yards - 990 985 967 feet/sec
Energy at Muzzle, 25yards - 320, 305 ft/lb