This 5 shot 7.62 caliber double action revolver is actually suppressed by its unique cartridge design.

When fired expanding gases from the gunpowder pushed a plug forward which inturn pushed the liquid solution (60% alcohol 40% glycerol). This incompressible solution pushed on the bullet to launch it out of the revolver’s barrel. The gases were contained in the cartridge preventing the typical sound report of a gunshot. And the liquid would follow the subsonic bullet out of the barrel as well.

https://guns.fandom.com/wiki/Gurevich_silent_revolver