The 45/410 was designed as a survival gun many years ago. It sells and therefore is still in production. I bought one to carry in the plane, but ended up using it to kill Halibut with. It's great for shooting bigger Halibut in the head with 410 shells, stops their flopping around.
Before someone makes a statement about hunting Halibut, no we don't hunt them. We catch them with rod and reels. But you don't want to bring a 100lb plus halibut into the boat till it's dead. One shot in the head is all it takes.