These are commonly called “combination guns”. Usually you get 2 different calibers, typically one shotgun and one in a rifle caliber. They were used in hunts where you’d encounter different types of game (requiring different calibers) or one type of game at different distances (imagine shooting relatively far at a large animal and using a rifle, then it turns and runs towards you so you can quickly switch to a shotgun with a slug load).

Often these are called “drilling” guns, with the rifle caliber in the middle. This one is fairly unique given the number of barrels, and that they all look like shotgun calibers. My guess the big one is probably a 10 gauge in the middle.

I usually associate these types of guns with African large game hunts, and British or German manufacturers.

These are pretty rare nowadays, they’re crazy heavy and modern loads can compensate for the shortcomings old loads encountered.