A load I've used for years in both my Colt Single Action .45 and my Ruger Blackhawk .45, is 8.5 grains Unique, a 255 grains hard cast Keith style bullet, and Standard Large Pistol Primers.

Gives plenty of power if needed, yet is easy on the revolvers.

My business load for the Blackhawk is 18.5 grains 2400, and 255 grains bullet. NOT for use in my Colt.

L.W.

Your new stampede should only be shot in the lowest pressure level. If I was to load for it I would not shoot a 255gr faster than 950 fps with appropriate powders. These are not strong guns like the Rugers.