Throats on the cast bullet revolver run right at 0.357" Have tried sizing to both 0.358" and 0.357". No difference noted.
Thinking that a lighter charge of HS6 might be a big part of the answer. Just have to find some. A friend found some Titegroup, going to try that as well. But will have to shoot the match tomorrow with 11gr 2400/ 150gr bullet. Can't back of it much more, starting to get inconsistant burn. Zero leading, though. Not something that can be said for any useful 231 load tried.

BTW, the newer 686 has 0.356" throats and shoots jacketed bullets better than any other S&W tried! So good in fact I'm using "el cheapo" Magtech 158gr JSP factory ammo for match fodder. Was cheaper to buy than reload...

marshall623 wrote:Jmoore My GP100 shoots that Lyman 358477 9.5 gr blue dot or 9.0 gr. of the old win 540 which some of the books say HS 6 & 540 are the same powder but I wouldn't hesitate to try HS 6. Mine does very well with those loads. That bullet with my 10" contender groups more like 000 buck. LOL

Finally found a couple of pounds of HS-6. Looks promising from several angles. Thinking about 7.0 grains to start, maybe a bit less. Need accuracy much more than velocity.

Seem to recall that HS-6 does better with magnum primers, but haven't yet found the references. Probably from the internet, so that's a big question mark!

A shooting friend of mine uses HS-6 in his 38 Super and uses standard pistol primers if that helps.

260 Striker wrote:A shooting friend of mine uses HS-6 in his 38 Super and uses standard pistol primers if that helps.

Thanks for that bit of info. have several old .38 Supers but have never done much loading for 'em. Mostly used as brass generators for the .38 Autos, but if this .357 Mag experiment doesn't go well enough to pursue further, then there'll be a fair amount of powder for the Colts.

Don't know why I can't get to a happy spot with the .357s and CBs. Have been doing OK with the .44s and .45 Colt.

Can't remember is you had tried Unique but 6.0 grains behind a 158 bullet usually works well in revolvers and should be good in your TC. Usually 357s and CBs go well together. I haven't shot many 357s recently so need to get them out and start shooting some. One grandson wants to shoot my GP100 so maybe I will stumble onto a load that might work for you. Keep trying, if you can find a happy spot for the 44s and 45s the 357s should come around too.

6.0 Unique and 158gr works for me.

2whlgeezer wrote:6.0 Unique and 158gr works for me.

No joy with that combo (cast bullets) for me. Same story with 231, blue dot, and titegroup. Jacketed loads have been ever so much better to the point of being ridiculous. And it's not just the one revolver. At this point i prefer to go to a larger caliber than shoot jacketed bullets and have done so.

Haven't yet started loading .357s with the new powder. Have spent the last couple of weeks depriming and cleaning 30 years of accumulated .45 ACP brass! Sorting in progress, Hopefully no large hidden stashes of that cartridge case remain...

Promising results with 158gr HiTek coated LSWCBBs over 7gr HS-6 at 100 yards. Best test to date with a scoped 686 test mule. It also shot an outstanding 10 shot 100yd group with some 158 plated bullets from Berry's that a friend loaded over a somewhat lighter charge of HS-6. There may be hope yet! Have lots of store bought Valiant 158gr bullets, so that's next to test. Weighed and sorted about 750 this weekend.

3.2 grains of WW231 Winchester with a WW small pistol magnum primer in Starline cases and an Ideal 148 grain wadcutter.

35isit wrote:3.2 grains of WW231 Winchester with a WW small pistol magnum primer in Starline cases and an Ideal 148 grain wadcutter.

I tried that. (maybe a tenth or two less powder...) Would have worked well but ran out of sight travel at 100yards! Ludricrous amount of drop. Had to add a strip of kraft paper to observe impacts below the 24" tall timed and rapid fire bulleye target. Must be the thick air. ;)