A compact firearm has a first frame portion including a barrel defining a barrel axis, a second frame portion including a firing mechanism configured to discharge a cartridge residing in a chamber of the barrel, the second frame portion pivotally connected to the first frame portion to pivot about a pivot axis offset from and parallel to the barrel axis, the first frame portion defining a first mating feature formed as a first surface of revolution about the pivot axis, the second frame portion defining a second mating feature formed as a second surface of revolution about the pivot axis, and the first and second mating features mating closely with each other to prevent relative movement between the first and second frame portions except in relative rotation about the pivot axis. The first and second mating features may be dovetail elements.