How far do you want to go back?
I'm looking at "The Complete Guide for Reloading" By Phil Sharpe. He shows two loadings for the 32-20, one for the Rifle and one for the Pistol. The round was originally produced for the rifle but Colt and S&W started offering chambering for it in their heavy revolvers.
According to Sharp, the rifle loading should not be used in the revolvers.
Rifle- The max Unique load shown for the 100 Grn Metal Cased is 6 grns giving the velocity of 1260 w/22,000 pressure reading.
Pistol-The max Unique load for the 100 grn MC bullet is 5.5 grns at 1065 FPS w/15500 pressure reading.
Thats quite a jump in pressure for only 1/2 gr. of powder.
This is just to give you an ideal, I haven't personally loaded for this cartridge.
CPT USAR Ret
USAMU Sniper School Oct '78
Distinguished Rifle Badge 1071