loplop:
If you scan back through this thread, you can see where I've reported some GDSB 38+P Replica Reloads--e.g., using a 140-gr. LTC bullet in either a 38 Special or a 357 Magnum case to obtain 860-900 fps. And, there has been good discussion of this general recipe in the reloading forum.
Here is a link to one of those threads.
There are widely-accepted parameters for the 38 Special "FBI load"--e.g., a 158-grLSWC-HP running, in its more-or-less last specification, at about 820-870 fps from a 2.5" or 3" barrel.
A 158-gr. LSWC-HP 38 Special reload at todays 38+P spec (18,500 PSI) runs almost exactly 800 fps from a 2" barrel. Obviously, you can build that up nicely in a 357 Magnum case.
FWIW, I think AA#5 is the the generally-preferred powder to do this with--it works great to build the 140LTC GDSB38+P (or 357 Mag) loads, and likewise with the "FBI-spec" loads. However, if you wander around some reloading forums, you will undoubtedly start hearing about "the Speer #8 loads" that use SR-4756 as the ultimate wonder powder for the FBI spec. It works--I've now shot a fair range of them--but IMO the real wonder powder for these two cartridges may well be Ramshot's True Blue.
Depending on your reloading skills, either practice ammo type (the GDSB 38+P / 140 LTC, or the FB1-spec 158LSWC can be readily built. At a cost of about 12 cents a round (amortized case usage, 10 rounds), it allows one to practice a lot.
I've done a lot of chrono work on the FBI-type load in the last couple of months, with several different powders--and the above general spec. is a good place to start.
As I mentioned above, the 900 fps / 158-gr. recoil is about the max I like to shoot to be able to do "quad fives" back-to-back.
Jim H.