Only 22 is ever really quiet (handgun rounds only considered since that is what was used)

You can use even cci mini mags out of a silenced handgun and still be subsonic and cycle most semi auto handguns in 22lr. The fps ratings are rifle based.

9mm are supersonic unless you deload or use 147gr bullets. Deloading will cause cycling issues. I have yet to try 147s in mine to say.