Paco Kelly, the lever-action guy, spoke very highly of the Puma in 454. It will tread close on the heels of the 45/70 if handloaded with 350-grain or so bullets.....

During the development of the 454, it was chambered in some Winchester 92 rifles. The problems they had were with the chamber of barrels expanding, not with action failures. The straight case grips thechamber walls quite well during peak pressure, lowering backthrust on the bolt. BUT specail alloy barrels were required to defeat chamber stretching. No doubt the Puma has the right stuff in the chamber region of the barrel....