That blast you hear is a LOT louder than supersonic 22lr's fired thru a good .22 silencer. So it's NOT "just sonic crack". Sonic crack with the .22lr is not very loud at all. I fired quite a few rds out of a silenced 10" barreled 1022 Ruger out of Panicki's south facing door in N. Spld Illinois, a neighbor's house being 40 ft in that direction and a neighbor to the north about 60 ft away. An truly effective can for the shorty 223 either has to be 1.5"x10", or 1.750 x 7.5". THEN the only noise is out of the ejection port and the sonic crack, IF you have the right guts in the silencer. I shot a steel disk with such a silenced AR in Pagosa Springs in the winter of 2005, neighbor's homes only 50m west of me. I parked the van in front of the overhead door of the storage unit and fired towards the south, 3x. No problems arose from it. THATS adequate suppression, folks. No, it was not subsonic ammo and no, I did not hold the bolt shut.