I suspect a person could shoot mild cowboy action loads from rounds like the 45LC and 44/40, as long as you kept it to bow-hunting distances. Personally, I've never been crazy about the idea of intentionally hunting with a gun that does not have the best possible ammunition in the chamber. Short of being dangerous, I believe hunting ammo should be loaded about as hot as you can make it, while still being very accurate. Maybe if I hunted with a cartridge like the 45/70, or one of the big-bore magnums, I might adjust that logic. For hunting with pistol rounds, like the two I mentioned above, I believe you owe it to the game to either keep the distances short, or the velocity up. Even with "hot" 44/40 (or my 44Mag) loads, I keep shots under 100 yards.