This is a decorative item which is part of a replica prop from "King of the Rocket Men."
The print slides over the front of a Luger pistol, hiding the original barrel. The CAD was made around a 1917 P08 with 82mm barrel, and requires the sight blade be removed from the barrel band. A void is included for a 1/4" by 1/8" deep super-magnet to hold the print to a metal replica gun.