From the NRA National Firearms Museum in Fairfax, Virginia, John Popp and senior curator Phil Schreier journey down into the vault to show us more of the museum's "twin" treasures. This time it's the Walther PP and the Walther PPK. The Polizei Pistole was introduced in 1929, followed by the Polizei Pistole "K" in 1931. The K refers to the police detective criminal division. Only a small overall change in size makes them different. Originally aired on Cam & Co 02/01/17.