A cylinder retaining mechanism for a firearm includes a frame having a firing bore and a cylinder having a longitudinal bore. A yoke is pivotally connected to the frame and is operatively connected to the cylinder for selectively pivoting the cylinder between a first position in which the longitudinal bore is aligned with the firing bore, and a second position in which the longitudinal bore is not aligned with the firing bore. A biasing mechanism is housed in the frame and has an engaging portion which is selectively accommodated within an engaging cavity formed in the yoke when the cylinder is in the first position.