The only silenceable revolver.
Source:Wikipedia.
As a general rule, revolvers cannot be equipped with a silencer, as there is usually a gap that exists between the revolving cylinder and the barrel over which a bullet must traverse or jump when fired. From this opening, a rather loud report is produced even when a silencer is installed on the end of the barrel of most revolvers.
Nonetheless, a silenceable revolver design does exist in the Nagant M1895, a Russian military revolver used from 1895 through World War Two. This revolver uses a unique cartridge that extends beyond the end of the bullet, and a cylinder that moves forward to place the end of the cartridge inside the barrel when ready to fire. This bridges the gap between the cylinder and the barrel, and expands to seal the gap when when fired. While the tiny gap between cylinder and barrel on most revolvers is insignificant to the internal ballistics, the seal is especially effective when used with a silencer, and a number of silenced Nagant revolvers have been used since its invention [1]
There also exists a modern revolver of Russian design, the OTs-38 [2], which uses ammunition that incorporates the silencing mechanism into the cartridge case, making the gap between cylinder and barrel irrelevant as far the suppression issue is concerned. Ironically the OTs-38 does need an unusually close and precise fit between the cylinder and barrel due to the shape of bullet in the special ammunition (Soviet SP-4), which was originally designed for use in a semi-automatic.