The MP412 REX is a Russian double-action .357 magnum revolver with a break-open frame and an automatic ejector. It was designed for export (REX, Revolver for EXport), but never put into full production due to lack of a market. The weapon was designed by IZHMECH, the state-owned Russian Izhevsk Mechanical Plant, which also designed and produced the Makarov PM semi-automatic pistol.
The MP412 appears in several video-games:
The gun was also featured in the video-game Red Steel, fulfilling the role of the magnum handgun found in many games of that type.