I own a FA .454, as well as two Ruger .480's, a SRH and a SBH Bisley. The FA wears a 10" barrel, MagNaPorted, while the SRH has a 7.5" barrel and the SBH is a 4 5/8" model.
Of these three, the SRH, with 425 gr. Grizzly ammo loads at 1200 fps, is by far the easiest shooter in terms of recoil with full-power loads, followed by the SBH and finally the FA .454. Full-power loads out of the FA are just downright painful, and it is difficult to shoot enough to become proficient with it without using reduced-power loads. Using Hornady 240 gr. XTP Mag bullets at 1450 fps, I find the Casull to be somewhat manageable.
The .480 Rugers, on the other hand, are routinely shot with my handloads of 410 gr. cast bullets at 1100 fps, and my practice sessions are both painless and productive.
I believe the difference in felt recoil between these cartridges has to do with the 60K+ pounds of operating pressure in the .454 Casull, vs. the 40K+ pressures in the .480 Ruger.
