In my friend's .325 WSM, I max it out at 71.5 grains with 150 gr Speers. I'd bet you'd be safe starting around 65 grains. Similar sectional density on 150 8mm and 130 .30 cals, just a bit of a change in bore to capacity ratio.

"For some unfortunates, poisoned by city sidewalks ... the horn of the hunter never winds at all" Robert Ruark, The Horn of the Hunter