This was a Winchester design dating from the late 1970’s to try and duplicate 357 Magnum ballistics in a semi-auto handgun. It was originally made for the Wildeypistol and later the AMT (Arcadia Machine and Tool) Automag 3. The guns were much too bulky for self defense carry and were more pitched toward hunting/target shooting. Ultimately it was not a success and faded into obscurity. (Erlmeier, Brandt Ref. 140A).