Yes you can shoot 45 Colt and 454 Casull in the 460 barrel. Some guns shoot the shorter cartridges well and others don't.
I have the S&W PC 12" revolver in .460. At 50 yds, I can just about put three bullets in one hole with Hornady's FTX loads. With my hand loaded Casull loads, 3 or 4 inches is about as good as it gets. As for the .45 LC loads... You wouldn't believe me if I told you. An Encore may be different though.
