I am using a B&T suppressor on a factory MP5. I have tried Hush 165gr rounds by Freedom Munitions, GTG 147gr rounds, Fenix 147gr rounds, IMI 158gr rounds, and American Eagle Subsonic rounds. I thought initially that the Hush 165gr rounds were the quietest, but with further comparison, it seems that the Hush 165gr rounds and GTG 147gr rounds are about the same, and the Fenix 147gr rounds seem to be a little quieter. What ammo have the rest of you tried with a suppressed MP5? Is anyone finding subsonic 9mm ammo available anyplace?