Winchester 748 propelent?

Win 748 is a rifle cartridge propellant and is not suitable at all for the .357 magnum cartridge - It's burn rate is far too slow. The .357 is still a pistol cartridge and needs a pistol powder, even you plan to fire it in a rifle.

Try Hodgdon 110 powder for the .357 magnum - it's about the most perfect powder I've run into for that cartridge. Other good magnum pistol powders are Alliant 2400 and Winchester 296. Get a load book or check the powder manufacturer's web site for the recommended charge weights.

I'd feel a lot more comfortable getting my reloading data from a familiar source, such as a reloading manual, rather then use something posted on here. It's too easy for people to make a typo, or just be dangerously WRONG. I wouldn't want to find out the hard way.

NO!

Consult a loading manual, PLEASE! Don't rely on data someone posts...Win 748 is a medium speed spherical rifle propellant.

If you want to load .357 look up H110, or HS7, or even Win 296...but stick to published loads!

check out midwayusa.com they have reloading data. you can google and find a PET load for that powder.