On the Hodgdon Powder Company's website they list Load Data for their products. A powder I've heard good things about is Lil'Gun. The data shows it producing impressive velocities and relatively lower pressures.
For the 100 grain SPR JHP bullet the MAX load comes in at 19,900 CUP and produces 1208 fps in a 5" Barrel.
I used the excellent RCBS 32-98 SWC with this powder and worked up to this load. At the MAX charge my 5.5" Ruger Single Six chronographed
The accuracy was impressive. It was pleasant to shoot though there was a noticeable fireball and the recoil felt similar to a 38 special in a small revolver.
The 1894 Marlin Cowboy this same load produces 1750 fps. The bore shows no signs of leading despite being a plain based bullet though the bore is left speckled with powder zombies. The accuracy was also promising though the range was too short to be conclusive.
More testing is required.