A buddy wants me to help him with 9.3x62 loads...
Think I'll try the Rhino's.
It pays to measure what the max COAL is. Most 9.3x62 have a really long leade. In mine, practically every bullet I measured would seat as far as as a max COAL of about 3.38". SAAMI spec on COAL for 9.3x62 is 3.29"
I just did some load development for 286 gr A Frames, set them to 3.32". With 62.5 gr of 2000MR under them, I'm getting around 2475 fps (measured with a MagnetoSpeed), with zero signs of pressure.
I did a 10 shot ladder, starting at 58.0 gr, proceeding in 0.5 gr increments. I very consistently got right at 20 fps improvement in MV for each half grain step. No sticky extractions, no deformed primers, nothing, all the way up to 62.5
I did the same ladder for 258 gr Shock Hammers, but set the coal at 3.30", last shot was measured at 2503 fps. I'm pretty confident I could get to 2600 or a little over with these, but 2500 for a 258 gr bullet with a BC of .431 and the way Hammer bullets are reported to perform is quite good enough.
I used Gordon's Reloading Tool to develop the loads, and it was showing MV quite a bit higher (nearly 200 fps faster) than what I measured with my chrony, so I talked to Charlie on the GRT discord channel. He helped me with the calculation once he'd done some of his wizardry. The predicted data I got back from him almost perfectly aligned with what I had observed. The dude knows what he's doing.
I'd recommend using a ball powder over a stick powder. 2000MR and Ramshot Big Game seem to perform the best.
muledeer over at 24 hour campfire forum has the data for Big Game. He's a writer (or was, I imagine he's retired) for a gun rag or 3, a big proponent of 9.3x62 with tons of research on it. His take is set the COAL to the longest length that will still fit in the magazine and then fill the case with all the powder that'll fit. I believe his max load is somewhere around 64 or 64.5 gr of Big Game.
If you can't get Alliant or Ram Shot powders in RSA, I imagine N140 would perform about the same.