Lyman 49th lists,
Unique 38 spl
Starting load of 4.7 = 645fps
Max load of 5.0= 710fps.
Max +P load of 5.2= 761fps.
OAL 1.480 for Hornady JHP #35750 158gr bullet
FWIW, my Speer manual shows this;
158 Grn Speer JHP:
Starting load of Unique: 5.0 Grns. (837 FPS)
Maximum load of Unique: 5.3 Grns.(918 FPS)
I find it interesting that the max load shown for a heavier bullet (160 JSP), using the same powder, primer, and fired from the same gun (a Ruger 6" Security Six) is listed as being .2 more, at 5.5 Grns.(928 FPS).
Also rather interesting is that it only took 4.7 Grns of Unique to push a 158 (swaged)LSWC to within 21FPS of the hottest-recomended JHP load.
No pressure figures are given for any of the above loads, but mention was made that the "starting loads" should be considered as max for small and alloy revolvers, and the "max loads" are for medium and large frame revolvers.
That said though, There weren't no SP101-type, heavy-duty, hide-out revolvers being made back then.
All used Federal standard primers.
All testing was done with a Ruger Security-Six.
Also....everyone concerned should remember that all 158 bullets aint the same. Some have a different crimp-groove placement than others, which in turn places one bullet deeper into the case than a where a different bullet might sit, which in turn reduces case capacity, which in turn causes otherwise identical loads to operate at significantantly different pressures.
I myself seemwed to have forgotten that. Had I been thinking more clearly, I would not have recomended any sort of a load to the OP without first asking some rather-revelent questions.
My apologies to him and the group.