I have been shooting 38 Spec. in NRA Action Pistol for years and right now, I think I am one of the few still shooting a revolver in Action Pistol. I am waiting to see if the auto loader thing is just a passing fad.
Granted, the Action Pistol Power Factor is only 120, but a very accurate load out of my 686 Open gun is a 148BBWC over 3.7 grains of WST. This chronos out to 870 fps out of my gun.
Using 125 JHP's, I load 6.0 grains of WST for an average on 1061 FPS. Both of these loads are capable of sub 2" groups at 50 yards. Unfortunatley, it usually depends on the nut behind the trigger.
As with any loading data, please reduce the loads and work up slowly.