I have three Ruger No.3s, .22 Hornet, .30-40 Krag, and (my favorite) .45-70. Also have a No.1 in .375 H&H, but haven't actually hunted with that one (weighs a TON, all barrel,
).
I also have a couple of T/C Contender frames and around a dozen barrels, mostly pistol calibers, but including .30-30 and .45-70.
Grew up bird hunting with single shot shotguns. For birds, a double or any repeater is far better. For other game, including big game, not quite as much.
A suitable single shot is fine for any game, but dangerous game. For the beasts that will hunt you back, and those that charge, a double is a LOT more comforting.
The big game double rifles from the classic era were favored by the Ivory hunters (and others) only partly because of their having a second shot instantly available if their first one didn't do the job, but ALSO because they used separate lockworks so that if something (broken part, etc) kept the first shot from firing, the odds of the same thing stopping the second shot were considered about zero.