Favorite .357 Mag loads w/HP-38

[ryan3465]

Hello All,

I am looking to cook up some midrange loads in .357 Magnum using HP-38. I have been shooting some loads i made up with 13.5 grn of 2400 with a 158grn LSWC but I don't want to rattle my K-frame Smith apart and I want a mid-power load to shoot. I tried 3.7grn of HP-38 under a 158grn LSWC and it shot pretty accurately, but was definitely a lower end load. Does anyone have any experience with this combination, and have any favorite loads? The components I will be using are Starline .357 Magnum brass, Winchester Small Pistol Primers, and 158 grain Hornady Lead SWC bullets. Thanks for any info you guys can give me!

 

[Curt Blunt]

You might try 4.5 to 5.5 grains. I assume you are using magnum cases?

 

[ryan3465]

Yeah, I'm using once-fired Starline 357 magnum cases. Ill try the 4.5 but I'm a little hesitant to go much higher, as the data on Hogdon's website says the maximum load is 4.7grn of HP38. I plan on working up from 4.0 grn but I was curious If anyone had any experiences with this combo

 

[Curt Blunt]

The web site shows 5.0 with a cast and 6.9 with a Hornady Jacketed 158.
The swaged Hornady is pretty soft so 4.5 might be a good max. I've used 4.0-4.5 Winchester 231 (which is supposed to be the same powder as HP-38) in the Special which was within Winchester specs prior to Hodgdon becoming the distributor. Has the powder changed or have the testing methods changed? I'm now using Red Dot in my light magnum loads so the question is kind of academic for me at this point but I think you are on the right track; you're gun will tell you what it likes and doesn't.

 

[joneb]

I like Curt's suggestions, a start load of 4.5gr W-231/HP-38 with WSP and 158 LSWC for 357 mag sounds good to me work up or down for the sweet spot. I would work up.

 

[ArchAngelCD]

Yeah, I'm using once-fired Starline 357 magnum cases. Ill try the 4.5 but I'm a little hesitant to go much higher, as the data on Hogdon's website says the maximum load is 4.7grn of HP38. I plan on working up from 4.0 grn but I was curious If anyone had any experiences with this combo

Like already said, Hodgdon lists a Max charge of 5.0gr HP-38 under a 158gr LSWC bullet and that's a light load. The pressures reported are only 23,900 CUP, hardly a Magnum load at all. Some Magnum loads on the same page are listed at over 43,000 CUP.

I have shot a lot of 5.0gr loads and they are fun to shoot from a 4" revolver...

 

[ryan3465]

Thanks everyone for the responses, I was mistaken on the max of 4.7grn (should know better than to try to recall from memory without the paper in front of me :banghead I'll be trying that 4.5grn HP-38 and working my way up if needed. Thanks again!

 

[joneb]

I was mistaken on the max of 4.7grn

Glad it didn't go the other way.
Check, double check and recheck.

 

[Hammerdown77]

4 to 4.5 grains is a 38 Special load. I found 6.5 grains of HP38 under a 158 gr. LSWC had the best accuracy out of my 686 4" gun and Ruger Blackhawk, while feeling more like a 357. It's nowhere near the recoil and blast of a standard 357 factory load, though.

 

[mbopp]

5.0gr of W231 in a 357 case pushing a Missouri hard cast bullet works in my K-frame. Probably too hot for a swaged bullet though.

 

[ryan3465]

Glad it didn't go the other way.
Check, double check and recheck.

That's right, sound advice jibjab. I guess that's one of the hazards of thinking about what might be a good load while I'm at work and don't have the manual in front of me! Glad the boss can't see inside my head! Thanks everyone!