I don't remember them using a .357 magnum in Olympic competition. I don't think the .357 was developed until the 1930s. (?) You might want to keep an eye on the online auctions, and the uncle might want to keep an eye on the local gun shows in his area. Have him report it to the police. When they stole it, did they take anything else? If not, it was probably someone who knew him. But you can pretty much figure that baby's gone.