I'm watching The Godfather, Part II where Vito Corleone goes to a house so his buddy can repay Vito for holding a bunch of handguns.
A police officer comes to the door, when they're rolling up the carpet.
Vito's biddy hides next to the door, with what looks like a top break revolver drawn. It's dark so it's hard to tell just what it is.
It makes me wonder, what NON-MILITARY calibers were were top breaks made in the 20th century?
This rules out Schofields, 44 Russians, military Enfields etc.