Lee #2, pg 670
Unique under a 230gr Jacketed bullet (no info for JHP, BTW):
Starting grains 6.0, never exceed 6.0, 16,000 PSI OAL 1.190
Lyman #48, pg 356
Unique under a 230gr TMJ
Starting grains 5.9 @ 12,500 PSI, never exceed 6.6gr at 15,800 PSI OAL 1.275
As I already demonstrated, Alliant's own website shows a load of 6.4gr Unique for a JHP at 230gr.
Also, look at .357 data. Page 556 in Lee #2 shows minimum charge of 7.2gr (max 7.8gr) Unique under a 158gr Jacketed bullet. Lyman #48 page 337 shows minimum charge of 6.4gr (max 8.3gr) in a JHP. Bullet construction is slightly different, but weights are the same.
What gets me is that Lee is not as accurate as others regarding minimum or maximum charges. In the case of the .357, Lyman exceeds Alliant's recommended charge for a 158gr bullet, but report the pressure at 38,000 as opposed to Alliant's rating of 33,000. That then becomes your decision to breach that pressure plane. Are you shooting a 30 year old Uberti cowboy clone that has been beat to hell? Better stick around 6.4gr @ 19,000 pressure. Or are you shooting one of the rare and cherished Redhawk .357's out there? Push it to 40,000 pressure, if it's in a condition to handle it.
According to Lee #2, though, you are wrong to drop below 7.2gr. But several sources discredit the Lee manual and demonstrate that the Lee minimum is not in fact the true minimum load available for the cartridge.