Abstract: A single-action revolver is disclosed which includes a cylinder frame and a cylinder to be mounted in the cylinder frame and a barrel removably connected to the cylinder frame. A center pin extends through the cylinder frame for rotatably mounting the cylinder within the cylinder frame, and a release plunger is provided for retaining the center pin in engagement with the cylinder frame in a conventional manner. The improvement is directed to interlocking means for retaining the center pin in engagement with the cylinder frame and includes a slot formed in the barrel and a collar formed on the center pin for engagement with the barrel slot to prevent release of the center pin. In addition, the center pin includes an additional notch for receiving the release plunger when the collar is rotated into engagement with the barrel slot. In this manner, the interlocking means prevent the center pin from being jolted loose during firing of the revolver.