A few years ago I read about someone playing with small cased wildcats. As an example 9mm para case necked to take a 22 or 6mm bullet has anyone heard of such an animal. I am interested in something along the lines of a 256 win mag with velocities around 1000 fps. A 300 whisper is too large of a bullet. This is a project for small (squirrel) critters. I would be using this with the explosive bullets such as the "Varmin-A-Tor " by Barnes or Sierra Varminter.