I'm confused by your reply. I'm well aware that P1 is the Bundeswehr designation for the postwar P38 based service pistol. However, I have a P1 and it is clearly marked on the slide "P1 Kal 9mm." I also have a commercial P38 and it is marked "P38 Cal. 9mm." I guess my question here regards your comment that the pistol in the OP is a P1. If so, why is it labled P38 vice P1? I do see that the receiver is stamped BW, but has the slide been borrowed from a commercial P38?P1 is the service name of Walther's P38. Walther always used the international caliber designation.