Hello Chuck,
I have a Marlin 357 also and have had it since Marlin first came out with it.
I use 180 grain cast bullets in my gun. I have a Saeco mold and I also buy some from Oregon Trails.
I use 13 grains of IMR 4227 behind the 180 grain plain base bullet. It will come out at 1320 feet per second. The pressure will run about 19,057 psi. Max pressure is 35,000 PSI.
My Saeco 180 home cast will print 20 shot group at 100 yards in 1.5" all day long. I have fired two 20 shot groups just to see if it would open up at all. I also, have fire many 5 shot groups with it at 1.5".
The recoil is very modest. With IMR 4227, you could run the velocity up to about 1440 fps with a maximum load. The case will only hold 13.9 grains of the powder.
I have tried numerous loads and the 4227 produces the best accuracy in my 357s. I have several handguns and actually, 2 1894s. One rifle shoots better than the other. I've used this load in the 6" revolver at the 200 meter Silhouette Range and it takes Rams at 200 meters (220 Yards).
The pressure numbers and velocity came from Neco Quickload Software that I have found to be very close to real life.
Harold Clark