Hmmm. Are you worried about recoil??
I can understand range rules limiting velocities so I understand what you're trying to do.
The reason I'm asking about recoil, is that you may want to try heavier bullets.
I used to load 135 grain cast bullets out of Ruger Blackhawk to keep the velocities down and still have some punch at distances up to 30 yards.
The Blackhawk is very strong, so I wasn't worried about pressures. The mold I used was made up by shortening a Lyman Aluminum set of blocks to get the weight I wanted.
I loaded that bullet up to appx 900 fps. I also tried slower velocities but accuracy wasn't good. I used 2400 powder if memory serves.
That was close to thirty five years ago. I sold that pistol to a farmer from Alberta. Don't have any idea wher it is now.