We use IR and silencers and they still run, the impact of the bullet hitting meat makes a loud pop and the bullet breaking the sound barrier cracks also.
Myself included, but people need to get educated on the fact that a silencer mutes (somewhat) the explosion in the chamber, but really has no impact on the missile/bullet breaking the sound barrier. I guess if you wanted to be (audio) effective, you would have a silencer and a sub-sonic velocity missile.
Then I guess using subsonic rounds is not the answer?