http://www.hodgdon.com/data/pistol/index.htm
Hodgdon lists this load:
10", XTP, 1.580" 18 gr, 25.8k cup, 1577 fps
The "Midway Loadmap" says 10" is:
17.3 gr, 30.4 kpsi, 1579 fps, 1.580" XTP FP
13.0 gr, 26.5 kpsi, 1378 fps, 1.580" XTP FP
17.2 gr, 35 kpsi, 1610 fps, 1.570" XTP HP
13.0 gr, 27.8 kpsi, 1390 fps, 1.570" XTP HP
If one belives Hodgdon's pressure and Midway's reduced loads, then a person could make 357 mag velocities at 38 special pressures.
Believe what you will, I have been shooting the 18 gr with various 158 and 160 gr bullets, and that load is a handful.
LIL'GUN is stange stuff. The gun kick something awful, and the brass and primer look like this is just another load.