Ruger Mark IV AND 22/45 Dual Phoenix Base Plate

A base plate designed to let a Ruger Mark IV or Mark IV 22/45 magazine function interchangeably in either platform. It also fits the Tandemkross lower, though it hasn’t been tested with additional aftermarket frames. The plate properly engages the magazine‑eject spring on both styles, ensuring correct operation.
On the 22/45, the profile is similar to a standard base plate but with a thicker, more reinforced end. On a standard Mark IV, the plate wraps around the magazine base and doubles as a small pinky rest.