Whats the difference in cast and Jacket loads?

[pdog]

I've been reloading since 1975, mainly jacketed bullets for handguns and rifles. In the mid-80's, I did reload cast for a 38 and 9mm somewhat. Now I have a 357 magnum Ruger 6" GP100 and want to load hot rounds for it. I have 500 midstates cast bullets without gas checks and no idea how hard they are. Looking at Hodgdons website and comparing cast to lead, a 158 cast with HP38 max load is 5.0 grns equaling 1108 fps. Same powder with a jacketed bullet starts at 6.2 up to 6.9. I'm assuming using jacketed bullets requirres more powder? Is there a estimated velocity to use gas checks or not? Basically, anyone have a good load for a 357 mag using 158 gn cast SWC's?

[That'll Do]

Here are some loads that work well for me using a 158gr SWC. (Note: I use mag primers with all my loads, along with 357 mag brass)

13.5gr Alliant 2400

7.5gr Alliant Power Pistol

6.0gr Alliant Unique

5.5gr Hodgdon Universal

For OAL, I seat them to the crimp groove and apply a firm roll crimp.

The 2400 load is my "hi test" load, the Power Pistol load is "middle of the road", and the other two are my plinking loads.

[waco]

all things being equal .....weight, powder charge.....cast will shoot faster

[Bret4207]

Try 5.5 -6.0 Unique. Nice safe plinking and field load in 357 brass. 5.0-5.5 in 38 brass in a medium frame revolver is certainly safe too.

I'd suggest you get hold of the Lyman Cast Bullet Handbook. Most everything you need to know will be right there. But Waco is pretty much dead on- cast generally has less friction and moves easier. BUT- the pressure curve is also changed and certain variations can create a higher pressure than jacketed though that's more or less unusual.

I would suggest sticking to mid range loads till you get the hang of cast. Work up slowly and observe. It's not difficult, just a little different.

[pdog]

On one of my other posts above here, someone said 7.0 Unique was ok. I assume to start with 5.5, 6.0, 6.5 and 7.0 and watch for flat primers etc. I do have a chronograph to check velocities also. Thanks for the info, just don't want to lead it up as its very accurate.