New to 10mm.

What's a good medium game load?  I'd prefer expanding bullets an the 170–200 grain range.

Does Winchester no longer make ST bullets for reloading?

Muchas gracias!

Having a 4" barrel you might want to use some of the medium burn rate pistol powders.  It would be hard to beat a 800X loading.  Powders like BE-86, Power Pistol, AA#7 would be good choices as well.  Blue Dot and Longshot would yield some good results as well.
We have a good collection of data here:
http://10mm-firearms.com/reloading-10mm-ammo/10mm-load-data-collection/

I have always have had good results with Hornady  XTP 180gr and 200gr and IMR 800X.  The best remedy for TX hogs is 200gr WFN hard cast and 800X.