From the information available, the Soviet design PSM was introduced around the
early 1970's to provide high ranking officials and military a small pistol for protection.

The 5,45x18mm cartridge is claimed to penetrate soft body armor, the pistol is
blow-back and very thin. These cartridges are very difficult to locate now in their
original military loading. Some reloaders are able to make the 5,45 cartridge out
of the 22 Hornet case. The Hornet case has the rim turned-off and a extractor groove
cut on a lathe. Reloading dies are available.

My photo shows some 5,45x18mm cartridges (original military load) with a 38 Special
cartridge for comparisonP1010043.jpg