I'm looking for a source for .357 Magnum data using Winchester small pistol primers (I have a whole bunch of them) and 158 grain cast bullets. I'd like to find a load that gets about 1200 feet per second.

Can anyone point me to a source for the data I'm seeking?

Thanks.

Speer lists 5.5 to 6.0 gns of Unique at 900 to 1034 FPS. Most cast loads are kept under 1000 fps due to leading from soft bullets.

The Lyman 48th has some load data for the .357 and lead cast bullets, and if you go over a 1000 fps. you may need to gas check your bullets, Sam has given you a good load start. But if you do'nt have unique then try AA#9, 2400,H-110,IMR or H-4227 you should find something there.

7 grs of herco.
12 grs of 2400.
with 158 gr cast boolits.
in a short 4" gun you'll need aa-9 or h-110/296
to reach the 1200 fps.
the 2400 might do it though.
and lead will not cram your bbl full of lead.
copper will foul out your bbl and burn it to pieces. kidding... rant over, but copper will wear out a bbl 10x times faster than lead.

Pushing 158gr cast at 1200fps from a 357mag
In what firearm??
Revolver
Slide gun
Gas gun
Lever rifle


Pushing 158's thru my S&W 586 w/ 8-3/8" bbl and WW-296 is 16.5gr

In 357 mag. Alliant 2400 @ 13gr. with a 158gr cast Lswc.

I'm working off the top of my head, but at 1200 fps you'll need a BHN of 16 or so to avoid leading. Above 1500 fps, you need hard-cast, BHN 21 or 22. At around 1700 fps, a gas check is needed to prevent flame cutting of the bullet's base and edge.