This is part of an article i found, Hope this answers your question.
Since its debut in 1955, the .44 Magnum has been the most powerful factory cartridge chambered in a double-action revolver from a major manufacturer. That lofty and lengthy status was shaken in January 1997 when Taurus announced it would be producing a double-action revolver chambered in .454 Casull. Many were doubtful this announcement would ever come to fruition, but the .44 Magnum's status officially toppled this past November when the Taurus Model 454 Raging Bull in .454 Casull became available.
Copyright National Rifle Association of America May 1998