Igm270,
A friend locked into the .358 Win gets ammo, not brass, from Cabela's and WalMart sales, uses the rounds and reloads the cases. I know that on occasion there are cases available from MidSouth, Midway or Graf&Sons, as he has purchased them from these folks when I have purchased some other components. He has told me that it is almost as inexpensive to get the loaded rounds during the Fall Hunting sales and then use them for practice. I also believe that he has told me there is no factory 250 grain loads available, the weight he reloads. He inherited his Win Model 88 in .358 and would not buy one in today's market, as if you want ammo for it on a trip, you may be SOL.