It is now obsolete and only offered as a chambering by custom manufacturers of single-shot firearm barrels such as Match Grade Machine and Bullberry.

From an 8.5 inch pistol barrel the 60 grain .256 Winchester factory load was advertised as having a MV of 2350 fps and ME of 735 ft. lbs.

This was 250 fps faster and nearly twice as powerful as the .22 Remington Jet, a varmint cartridge for revolvers that was also based on a necked-down .357 Magnum case.

Winchester .256 factory loads used a 60 grain Open Point Expanding bullet at a MV of 2760 fps and ME of 1015 ft. lbs.

The .256 Winchester Magnum was chambered in a very small selection of firearms, and never achieved great commercial success.