How much sound will be cut down by a suppressor on a .223? isn't it the round breaking the sound barrier that makes the most noise?  I've never shot a suppressed weapon, just curious.

The sound comes from both the muzzle blast and the sonic boom. The sounds are different and the blast is the loudest. They will still hear some noise but the noise will not come from the same direction as the Muzzle blast would have. They will still hear the shot but have harder time determining where it came from. I am not an expert at this so I may be wrong, whops I am never wrong, so I should say I may not be 100% correct, now that’s better.  Have a nice day.