Tom and John,
Some 60 years ago, I too was very supprised when I had the opportunity to participate in the firing of a silenced Rifle firing 22 long rifle High Velocity (Supersonic velocity) cartridges and 22 shorts (Subsonic velocity).
Holding the rifle vertically and firing 22 long rifle High Velocity (Supersonic velocity) cartridges, was shocking, the only sound was the sharp snap of the firing pin.
It sounded exactly the same as dry firing, just a click. <img border="0" title="" alt="[Eek!]" src="eek.gif" />
(We were so shocked that we pulled the bolt from the rifle and looked through the barrel to determine whether the projectile was not lodged in the barrel)
When fires horizontally there was the same silenced click of the firing pin followed by the echo of the projectile traveling supersonically and creating a shock wave cone that reverberated off of any object as it traveled away.
It appears that there is no sound within a cone of silence that travels forward away from the muzzle.
As one moves from behind the rifleman out to the side and forward the sound starts to appear at approximatly 45 degrees and increases until at 90 degrees the sound is no different than a rifle fired with no silencer.
The noise at the range was probably the Echo from the sound buffer that hangs just forward of the firing line.
Firing 22 shorts which traveled at subsonic velocity resulted in total silencing of the muzzle blast and there was no shock front developed by the projectile and the result was as silent as dry firing from any location.
I stood around a corner out of sight of the rifle but within 3 feet of the projectiles path and heard only a sound similar to that sound made by a fast thrown baseball passing close to the head.
Just a soft whoosh.
I'm still trying to settle my mind on the formation of the cone of silence where the rifleman and all behind him heard nothing and every one ahead of the muzzle could not tell that the rifle had a silencer. <img border="0" alt="[cherrsagai]" title="" src="graemlins/drink.gif" />
ViggoG