Today, we have a chance to take a look at a suppressed M3 “Grease Gun”, as purchased and issued by the Office of Strategic Services (the OSS; predecessor to the CIA). Thanks to its readily removable barrel, the M3 (and M3A1) submachine gun was an easy gun to adapt to use with a suppressor (or as it was called at the time, a silencer). During World War 2, such a unit was developed for clandestine use by OSS and British SOE agents in occupied Europe, and they would see use for many decades in all manner of conflicts.
The suppressor itself is quite different than modern designs, being a two-part device using tight wire mesh instead of baffles. The barrel itself is heavily perforated, and extends only through the large diameter section of the suppressor. Around it is wrapped a large roll of wire mesh, which acts as an expansion chamber to slow down the exit of gas from the muzzle. The smaller front section of the unit is filled with small discs of the same wire mesh, similar to wipes but made of mesh.
Allegedly, the suppressor was effective enough to reduce the noise of the gunshots below the level of the action cycling, which is all that one can reasonable want from a suppressor. This particular example has an excellent provenance, having been provided by OSS to a European resistance fighter for a specific mission right at the end of WW2.
In addition, we also have a piece of the OSS sneaky tricks catalog to see. Specifically, a “Bushmaster” remote trigger mechanism to allow the M3 (silenced or otherwise) to be made into an autonomous booby trap in conjunction with a time delay, tripwire, or other triggering device.
Many thanks to the anonymous collector who let me take a look at this piece and bring you a video on it!