OP,
My reloads for x39:
Sierra 220gnRN .308, 6-11gn Unique. Subsonic 760fps to 1080fps in NS. (low end would not operate gas mechanism, high end would, but not every time).
Mexican match 125gn Hornady shot 3 deer.
Mexican match 150gn Hornady, removed 2gn original powder (worked in my rifle). Powerhouse round from the SKS.
Mexican match 174gn RN Hornady, removed 3.5gn powder. 1960 fps.
Currently, if using SKS for hunting, I will not use commercial brass unless I remove the operating rod. Don't like losing hard to get brass.
I only use PRVI (125gn @ 2435fps from my rifle) in my 799 since it is the best way i know to get good brass and I can shoot a fair bit at under $1 a round. They have accounted for their share of deer, but once I have a couple of hundred rounds, I will switch to 150gn to extend my range. Right now, range and shot placement are CRITICAL with it.