Here's a 'factory' .358STA:
Brass can be obtained with the proper headstamp from Quality Cartrdge. Ever since I first read about this round in circa '96 I had to get one.. The one pictured above has never been fired - it's NIB.
But I built one for myself out of a Rem 700 that was previously a 7mm RM... There's nothing in NA that it can't take with aplomb.. .338s and .375s are all over the place - but if you desire something very few others have - then this is the round..