For a first stop, try Cartridges of the World. I'm at the office right now, but I'll check this evening and see what my various issues say.
Generally, though, I think you're going to have this problem in finding data for rifle rounds for the .32-20. It's not really a popular cartridge anymore, and concerns about putting souped up .32-20s into an old Colt or S&W probably is the biggest reason for this, especially after the bad experiences with the Winchester High Velocity ammo,
"The gift which I am sending you is called a dog, and is in fact the most precious and valuable possession of mankind" -Theodorus Gaza
Baby Jesus cries when the fat redneck doesn't have military-grade firepower.