Choate Winchester 70 Short Action Varmint. This high performance stock was designed by Major John Plaster (US Army, Retired). He is considered by many to be one of the world's top authorities on long range, highly accurate shooting.
Will not fit Super Short magnum .243
Here are some dimensions that might help you identify your receiver length. These are the distances between the two receiver screws: Winchester short action 7.031 / long action 7.570