I recently picked up a large number of 357 brass casings and would like to reload them with 148 g. wadcutters, both HB and DE. I've researched this and found several recommendations, among them: load the same as for the .38, or up the powder load a tenth of a grain or 2 to make up for the expanded case size. I now load 2.7 grains BE or 3.1 W231.

Steve - I would not be surprised that you'd be able to bump these even one or two tenths above your new estimated levels.
A 38 Spl load for a model 52 I've seen that people even had to bump that up to 2.9g just for satisfactory functioning so IMO - 2.9 in a 357 case should be no big deal at all. I'd say the same for your WW231 loads.

I shoot 4.0 gr. of Red Dot with a 148 gr. DEWC in 357 cases. Made 760 fps from a 4 inch 586 and shoots pretty well. Dean

Hornady 148gn HBWC
3.4gn 231
357 Win brass
WSP
627 w/ Bushnell 2-6
50 yd.......

Same load as mentioned above
Two strings of six shots fired freestyle in 20 sec each at 50ft
686-6 6"

About 30 years ago I bought a M52. It just didn't want to function with 2.7 gr of Bullseye. So I bumped it up to 3.0 and the gun was a whole new animal. Never even a hint of a problem.

The loads we see in manuals is the lowest load they recommend. It certainly isn't a pressure limit. There are lots of reasons to push too much, with leading being one of the big ones. I'd guess you could boost the load another half grain or more and no pressure signs would be seen.

I'd guess the real problem with loading 357s with wadcutters is you can't use them in 38s. If you want to replicate a specific 38 load, get a Chronograph and load to the same basic average velocity. You may see a slightly higher variation with the bigger case, but probably not enough to be significant, or cause an accuracy difference.

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Dick Burg

I don't use Bullseye but I use a lot of W231.

With a 148gr DEWC I charge between 3.2gr and 3.4gr W231 in a .38 Special case. In a .357 Magnum case my charge weight is 3.5gr W231 under the same bullet. It's a soft shooting and accurate target load.

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Freedom is never free!!
SWCA #3437

Double Ended WC's can be loaded like any other solid bullet from light to heavy.

HB WC's need to be loaded to a relatively light pressure level so the hollow skirts do not expand so tightly they rip off in the barrel leaving a bore obstruction. Use data found in the manuals. If you use mag primers in your .357 mag loads the pressures will generally be higher, this is why the data for W231 from Hodgdon lists less powder in the .357 mag than in the .38 spl with standard primers.