They are by no means the most effective suppressor setup, but they do reduce the signature just enough to make the signature harder to pinpoint. I think the idea was to run a .38 subsonic of some sort as the ammo, which would have cut the signature down a little more.Some experimental Dan Wesson Suppressors were in fact made in an attempt to see IF by reducing cylinder-forcing cone gap, the noise signature could be reduced. It didn't work out. They were never a team issue item.
Main problem was 357 Mag is supersonic....reducing velocity to sub sonic means 38 Special.
Many prototypes are made for LE and Spec ops...you may have fired one.
They were never purchased or assigned a national stock number (NSN) as they were just another technology experiment that verified why revolvers are not supressed.
The original question was regarding silencers for revolvers.
In practical terms, it doesnt work. If legal in your state, buy one in .22lr and you will have more fun than you can imagine !
I have mentioned on another thread before, Joe Peters (of Peters Stahl GmbH) built silenced revolvers which where tested by the German GSG9, I remember being at one of the last Bisley shoots and shot it myself. Whether or not GSG9ever ordered it I don't know, but I assure you it was built.http://en.wikipedia.org/wiki/Revolver#Use_with_suppressors
I have been in the LE/Spec Ops community for 40+ years and licensed to manufacture supressors...I have built and tested many designs. I know of what I speak.