The Rossi is also chambered in .454 Casull. So, strength of the action is unquestioned.
Loaded with a Lee 310gr RFN-GC @ .460” with Ruger “only” loads of #2400 or H110, It approaches a factory.45/70 (@ trapdoor pressures).
It is over powered for anything in the lower 48 save moose or black bear.
My favorite load for both my S&W 625 and Win. M94 is the Lee 255gr RFN over 8.2gr of Universal or 9.8gr of LongShot. My buddy using a Taurus Thunderbolt shot a 100lb doe lengthwise with an exit. You could eat up to the bullet hole...
We shot a bunch of armadillos on that hunt. Impact of bullet is louder than gun shot! Think a bass .22lr with a sonic “crack”. (1,200fps from 24”bbl).