I use the PPU bullets fron Krank's. Either the 170 0r 174 weights. N140 works fine.

I shoot cast in my Mosins all the time. I use the Lee .312-185, my mould casts out at .316" and I size to .315. Best loads with N140 pushes these out at just under 2200 fps. Slug your barrel before using cast, I have examined two unfired Polish M44s when they were first imported in the 1980's, I actually opened the crate, and both were over .318", so no good for cast unless I had a custom mould.