Ruger Hawkeye

The Ruger Hawkeye was a single-shot pistol chambered for the .256 Winchester Magnum cartridge, produced by Sturm, Ruger in the 1960s. It was built on the same frame as the Ruger Blackhawk, but rather than having a rotating cylinder like a standard revolver, it featured a swiveling breechblock which allowed an individual round to be loaded and sealed into the frame.

The pistol was not a commercial success, and was discontinued after a short run.