here is an example where a .416 would be at least a MINIMUM. i would also suggest a very magnum chambering and a very solid bullet.

A laser sighted 60mm harpoon cannon with a penthrite grenade tipped harpoon is what the Norwegians are using on minke whales. And the Greenlandic Inuit are using the same combo on their small quota of fin whales, which are the second largest of the rorquals at about 80 feet and 60 tons.

A rifle is just used to ensure death as the whale is winched alongside the catcher boat.

Up here most of the folks use a 4 or 8 bore black powder shoulder fired gun to deliver an exploding projectile at close range. From what I've seen and read, it is very dangerous. I am not allowed to participate, but I really want to. The projectile penetrates the baleen whale and then explodes inside the beast, resulting in a quick clean kill. This is big game hunting. I have seen a shop in Barrow that sells the exploding projectiles. I love America.

as is probably obvious, i started this topic as a joke!

great to see some "bona fide" answers!