Same gun, better (read tougher) cylinder and barrel material. The very slight extra cylinder length is on the case rim side to compensate for the counter boring. They are considerably lighter than a BFR, and the recoil between the .454 and .480 is what you would expect, the Casull being a lot faster and sharper versus the big push from the .480 (assuming heavy loads in both). Both of mine (the .454 and .480) are exceedingly accurate. Fit and finish is okay, and about what I expect. They both have the longer ejector rod housing as well. I'm really happy with the way they perform.
