I wanted to share some data that I worked up for my 9.3x57. I know load info is sparse for this cartridge, so hope this helps.

First, the disclaimer. Start below the loads below and work-up. Check speeds and cases.

My rifle is a 1930's German guild rifle built on a M98 action, not a M96. It has a light profile 24" barrel. And it's 6.5" pounds and iron sights. It kicks a bit!

My base comparison is Norma factory ammo loaded with 286 gr Alaska bullets. Published factory fps is 2,067 (I never checked). The Norma factory load showed a slight bulge at the base of the case. My goal was to match factory published specs and not exceed the case bulging of the factory ammo.

Load Info:
Brass: Norma
Bullets: Woodleigh 286 gr RNSN (use the Woodleigh PPSN for 9.3x62 and above)
Powder: IMR-4064
Primer: CCI-200 LR
COL: 3.035" w/crimp
FPS: Measured at chronograph at 10 ft from barrel

48 gr - 2,133 fps to 2,168 fps spread on 4 rounds, case bulge more than factory Norma
**** 47 gr - 2,085 fps - on 4 rounds (exact same fps on each), case bulge equal to or less than factory Norma
46 gr - 2,003 fps to 2,019 fps on 3 rounds
45 gr - 1,974 fps - 1 round

I settled on the 47 gr load. Obivously, check loads with different lots of the same powder.

I saved the remaining 46 and 45 gr rounds to shoot at some hogs that weekend.

I have used 41.0 grains of AA2460 behind a Prvi 285 for years. I use this in my Husqvarna M46's. Easily capable of 1" groups with the iron sights.

For my 146's I will use a stiffer load of RL15.