I' ve watched and no one has replied and I think there' s very little loading data available.

You can buy loaded ammo here: www.owlnet.com/quality/358%20STA.htm

If I had one I' d start with loads for the .358 Norma Mag and work up from there watching for pressure signs if I couldn' t get loading data. I' d also fire the first shot with a string from around a corner.

I' ve rebarreled many a gun and always fire the first shot from a remote position.