HP-38 For .357's

[Ky Larry]

I'd like to work up a load for .357 Mags using HP-38 powder and 125 LRN bullets. I'll be using once fired Remington plated brass. Can someone suggest starting and max powder charges. Also,which CCI primer should I use?
Thanks.

 

[helpwanted]

Lee manual lists a 357 mag load with hp38 and 125 grain lead bullet:
start: 4.6 grains/1052 fps
never exceed: 5.5 grains/1185 fps/18800 CUP/1.580 min OAL.

 

[Ky Larry]

helpwanted, did the Lee manual list a primer?. Specifically, did it list a small pistol primer or a magnum primer with this load? Thank you for your help.

 

[helpwanted]

Doesn't specify a magnum primer, so standard will work.

 

[Ky Larry]

helpwanted, thank you.

 

[Mark whiz]

you can use either standard or magnum primers in that load. I've chronyed both and there is VERY little difference - not enough to even worry about.
PERSONALLY I would use the magnums since HP-38 (pretty much the same powder as Win 231) is a ball powder and magnums usually ARE recommended for ball powders.

 

[helpwanted]

ball powder aka spherical?

 

[Mark whiz]

ball powder aka spherical?

that is it exactly. Spherical or even flattened spheres. This is opposed to flaked powder or extruded (rod-shaped) powders.

 

[anonanon]

I've found HP38 a great powder for low velocity wadcutter loads, but it burns too fast for magnum loads. I have to take the manual writers' words for pressure, and the hottest I've seen from Hodgdon with a max of 8.5 gr at 42,700 CUP and 1514 f/s in 10" bbl. But I gave up on HP38 at anything over 5 gr; groups scatter like buckshot compared to the magnum powders.