Tried to post earlier but the site went down - oh well.

Nice ctg. and good technique.

I used 8x57 RP brass for my 9.3x57 and got excellent results as there is no 'dreaded donut' left by the neck/shoudler junction when using the 8mm brass.

I necked up the brass to .42 cal, then down to hold the 9.3" bullet only until closing the bolt was stiff. This ensures 0 headspace, as you've done. My rifle had .019" headspace and should never have left the factory, but did. It shoots sub MOA with all bullet weights from 225 to 300. I use H4895 or BLC2 for all loads now.
If you want to PM me, I'll give you a run-down of the loads as H4895 has a direct relative in an ADI powder. They would work for medium pressure loads with identical bullet weigths in your 9.5 due to your larger bore. I was barely getting any case web expansion (.0005) and barely any case mouth expansion(same 1/2 thou.) with most of my loads and managed 2,200fps with 286gr. bullets, & 2,300fps with 270's from a M46 Husky with a M94 Mauser action.