[myfriendis410]

There are a number of powders that will get you where you want to go with careful load workup. In the 45/70 I regularly use IMR4198 and RL7 with low pressures and decent velocities. The cases fall out of the gun and the primers are rounded, but no blackening of the brass to indicate pressures so low the case fails to seal. Do a little research and you ought to get a good starting load to work with.