WST for light 357 loads?

[Waffen]

I recently purchased a 77/357 and had it threaded for a suppressor. I've been feeding it full power loads since I got it, but I'd also like to shoot some subsonics through it. That said, I don't have any powders that are ideal for 38 special loads, but I do have ~7lbs of WST that I keep on hand for 45 ACP. I've looked, and Hodgdon has data for the 38 special and WST, but the velocities they're posting are extremely low (i.e. ~700 fps out of a 7.7" barrel). I wouldn't normally be leery of that, except I intend to use 357 brass and, I'm shooting this out of a 16.5" barrel; admittedly have concerns I'll stick a bullet if I used the published 38 special load, and with a suppressor I may not know know it until it's too late.

Hodgdon lists their max 38 special charge as 3.7gr @ 770FPS. I know WST is a fast powder, so I know to be careful when upping the charge weight, but I was thinking of starting around 4.2 with a 158 cast bullet, and seeing what happens. I'm not looking for major accuracy here, just something to make it whisper quiet plinking.

Anyone see any issues with that, or messed with WST in a 357 before?

 

[Walkalong]

3.8 Grs of WST under an X-Treme 158 gr SWC @ 1.560 OAL gives me about 700 to 725 FPS from a 6" revolver powder back. Powder forward drops that to about 575 to 600 FPS, which is as low as you want to go.

It is light, fun, accurate, and very clean.

Try 4.0 Grs. That and being a lead bullet vs plated should make sure the bullet leaves the barrel every time regardless of powder position. Do check when testing though. Be dang sure all bullets exit the barrel when testing.

 

[stubbicatt]

Waffen, if you wish to experiment with WST in the 357 case, if it were me doing this, I would start with the max 38 load, and run a few with .01 incremental increases until I saw signs of good sealing with the cases, and verify a hole in the target before chambering another round.

If it helps at all, using 5 grains of 231, a 160 grain RNFP Lyman bullet, and I'm getting just over 1100 fps. from 20" barrel. That might be a starting place? Or perhaps run some 180's or 200's, that way you can dip into known published powder charges and still obtain the velocity window you seek? I have found that with "velocity challenged" cartridges, often heavier slugs will perform really well.

Another thought, which I don't like to do, but if you are using only a few of these subsonic rounds, maybe load 38 specials? I don't like to do that because I don't like that ring of fouling that builds up in the chambers, which I find hard to remove.