Private First Class John T. Fields, aircraft armorer of the 100th Fighter Squadron, 332nd Fighter Group, 15th Air Force, checks the magazine feeds of the Browning .50 caliber machine guns on a North American P-51B Mustang. Note the angled guns for optimum armament entry. During the period this photo was taken, the 332nd was engaged in frequent ground strafing of Axis airfields in Hungary, Austria and Italy. Behind Fields is the P-51B Mustang "Stinky II." Before each flight, the plane's armorer would seal the machine guns with tape to prevent moisture from forming ice in the guns at high altitude, which would cause them to jam. Since most of the 332nd's fighters were hand-me-downs from other groups, they were often war-weary aircraft and had frequent malfunctions. The P-51B had four machine guns; the later D-model had six.