The RSh-12 (Russian: РШ-12; Револьвер Штурмовой калибра 12,7 Revol'ver Shturmovoy kalibra 12,7; meaning "12.7mm Assault Revolver") is a Russian large-caliber revolver, first showcased in 2014.
Only one known photograph exists for the weapon, showing a seemingly stress-tested prototype marked with serial number 100001.
The revolver fires from the bottom cylinder instead of the much more common top cylinder, which is similar to the Mateba autorevolver and the Chiappa Rhino. This reduces the recoil due to being closer to the axis of the shooter's hand.
The barrel is reinforced with a casing with ventilation holes, making it visually somewhat similar to the aformentioned revolvers. Picatinny rails are present both above and underneath the barrel.
The cylinder is pentagonal, and is apparently both a top-break cylinder and a swing-out cylinder.
Attachments the revolver is known to be able to use include a removable collapsible butt stock, an underbarrel foregrip, and a silencer. The use of a silencer may suggest that the revolver incorporates a gas-seal design seen in older Russian suppressed revolver designs, such as the OTs-38 Stechkin or the Nagant M1895.
A very similar large-caliber Russian revolver is seen in a photograph of a Russian arms show, but is not confirmed to be related to the RSh-12.
This revolver features a traditional cylindrical cylinder and larger ventilation holes. It still has some of the RSh-12's distinctive features, such as firing from the bottom cylinder.