I'm thinking about a single shot for a 'truck' (Rover and little old Bronco, actually.) gun; reasoning that it'll, actually, be the quickest from unloaded for safety to a shot fired and very compact.
This is the current leading candidate:
Model: 1885 TRAPPER
Caliber: 30-40
Barrel Length: 16.5"
I've had very few singles, so more experienced opinions on both my reasoning and rifle choice are very welcome.