Hornady manual

S & W Model 39
4", 1 in 10" Twist Hornady/Frontier Winchester WSP

Powders that worked exceptionally well in our test weapon were Accurate #7, and Alliant Power Pistol.
Velocity differences between 4" and 5" barrels were negligible.
What’s interesting is they show a larger max charge of 7.9 grains Accurate #7 only pushing to 1150 and from what I understand, their recommended max loads are usually on the conservative side.