This my current test. 115 gr SWC on a 95g CamPro. Total 205 gr.
357 case with 2400. Cases were already primed with a S&B standard primer. 2400 really needs the magnum primer, otherwise ignition is poor and the ES is high.
I loaded 5 rounds with 9.5, so I could shoot 3 at a paper target (5, 10 and 15 yards) and then 2 at the chrony.
On paper, at 5 yards the two bullets were 1/4" apart.
at 10 yards they were 1/2" apart.
At 15 yards, 1 inch apart. (You can't see the bullet kissing the edge of the paper in the picture.)
I also loaded 2 each of 10.0, 10.5 and 11.0 for the chrony. I was looking for 1200 fps. Did not quite get there. 11.2 would be about right.
For a 38SPl, 7.0 gr of 2400 is about max at 850 fps.