Trail Boss leaves a lot of residue, a bunch of little unburned donuts. I don't like it.

I think you could safely shoot .45 Colt cowboy action loads in that gun without a problem. There isn't that much more space in the .454 case than in the .45 Colt. Another thought is using long nose lead bullets in .45 Colt cases. You just need the right COAL, the Rossi will never know, or care how you got there.

You can get a bunch of CAS data on line. I like Clays, but many good, clean powders are available for that application.

Clean is key, IMHO.

DF